1
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Pfannerstill EY, Arata C, Zhu Q, Schulze BC, Ward R, Woods R, Harkins C, Schwantes RH, Seinfeld JH, Bucholtz A, Cohen RC, Goldstein AH. Temperature-dependent emissions dominate aerosol and ozone formation in Los Angeles. Science 2024; 384:1324-1329. [PMID: 38900887 DOI: 10.1126/science.adg8204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 04/22/2024] [Indexed: 06/22/2024]
Abstract
Despite declines in transportation emissions, urban North America and Europe still face unhealthy air pollution levels. This has challenged conventional understanding of the sources of their volatile organic compound (VOC) precursors. Using airborne flux measurements to map emissions of a wide range of VOCs, we demonstrate that biogenic terpenoid emissions contribute ~60% of emitted VOC OH reactivity, ozone, and secondary organic aerosol formation potential in summertime Los Angeles and that this contribution strongly increases with temperature. This implies that control of nitrogen oxides is key to reducing ozone formation in Los Angeles. We also show some anthropogenic VOC emissions increase with temperature, which is an effect not represented in current inventories. Air pollution mitigation efforts must consider that climate warming will strongly change emission amounts and composition.
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Affiliation(s)
- Eva Y Pfannerstill
- Department of Environmental Science, Policy and Management, University of California at Berkeley, Berkeley, CA, USA
| | - Caleb Arata
- Department of Environmental Science, Policy and Management, University of California at Berkeley, Berkeley, CA, USA
| | - Qindan Zhu
- Department of Earth and Planetary Science, University of California at Berkeley, Berkeley, CA, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, USA
- NOAA Chemical Sciences Laboratory, Boulder, CO, USA
| | | | - Ryan Ward
- NOAA Chemical Sciences Laboratory, Boulder, CO, USA
| | - Roy Woods
- Department of Environmental Science and Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Colin Harkins
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, USA
- Department of Meteorology, Naval Postgraduate School, Monterey, CA, USA
| | | | | | - Anthony Bucholtz
- Department of Environmental Science and Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Ronald C Cohen
- Department of Earth and Planetary Science, University of California at Berkeley, Berkeley, CA, USA
- Department of Chemistry, University of California at Berkeley, Berkeley, CA, USA
| | - Allen H Goldstein
- Department of Environmental Science, Policy and Management, University of California at Berkeley, Berkeley, CA, USA
- Department of Civil and Environmental Engineering, University of California at Berkeley, Berkeley, CA, USA
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2
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Pfannerstill EY, Arata C, Zhu Q, Schulze BC, Woods R, Harkins C, Schwantes RH, McDonald BC, Seinfeld JH, Bucholtz A, Cohen RC, Goldstein AH. Comparison between Spatially Resolved Airborne Flux Measurements and Emission Inventories of Volatile Organic Compounds in Los Angeles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:15533-15545. [PMID: 37791848 PMCID: PMC10586371 DOI: 10.1021/acs.est.3c03162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 10/05/2023]
Abstract
Los Angeles is a major hotspot for ozone and particulate matter air pollution in the United States. Ozone and PM2.5 in this region have not improved substantially for the past decade, despite a reduction in vehicular emissions of their precursors, NOx and volatile organic compounds (VOCs). This reduction in "traditional" sources has made the current emission mixture of air pollutant precursors more uncertain. To map and quantify emissions of a wide range of VOCs in this urban area, we performed airborne eddy covariance measurements with wavelet analysis. VOC fluxes measured include tracers for source categories, such as traffic, vegetation, and volatile chemical products (VCPs). Mass fluxes were dominated by oxygenated VOCs, with ethanol contributing ∼29% of the total. In terms of OH reactivity and aerosol formation potential, terpenoids contributed more than half. Observed fluxes were compared with two commonly used emission inventories: the California Air Resources Board inventory and the combination of the Biogenic Emission Inventory System with the Fuel-based Inventory of Vehicle Emissions combined with Volatile Chemical Products (FIVE-VCP). The comparison shows mismatches regarding the amount, spatial distribution, and weekend effects of observed VOC emissions with the inventories. The agreement was best for typical transportation related VOCs, while discrepancies were larger for biogenic and VCP-related VOCs.
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Affiliation(s)
- Eva Y. Pfannerstill
- Department
of Environmental Science, Policy and Management, University of California at Berkeley, Berkeley 94720, California, United States
| | - Caleb Arata
- Department
of Environmental Science, Policy and Management, University of California at Berkeley, Berkeley 94720, California, United States
| | - Qindan Zhu
- Department
of Earth and Planetary Science, University
of California at Berkeley, Berkeley 94720, California, United States
- Cooperative
Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder 80305, Colorado, United States
| | - Benjamin C. Schulze
- Department
of Environmental Science and Engineering, California Institute of Technology, Pasadena 91125, California, United States
| | - Roy Woods
- Department
of Meteorology, Naval Postgraduate School, Monterey 93943, California, United
States
| | - Colin Harkins
- Cooperative
Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder 80305, Colorado, United States
- NOAA Chemical
Sciences Laboratory, Boulder 80305, Colorado, United States
| | | | - Brian C. McDonald
- NOAA Chemical
Sciences Laboratory, Boulder 80305, Colorado, United States
| | - John H. Seinfeld
- Department
of Environmental Science and Engineering, California Institute of Technology, Pasadena 91125, California, United States
| | - Anthony Bucholtz
- Department
of Meteorology, Naval Postgraduate School, Monterey 93943, California, United
States
| | - Ronald C. Cohen
- Department
of Earth and Planetary Science, University
of California at Berkeley, Berkeley 94720, California, United States
- Department
of Chemistry, University of California at
Berkeley, Berkeley 94720, California, United States
| | - Allen H. Goldstein
- Department
of Environmental Science, Policy and Management, University of California at Berkeley, Berkeley 94720, California, United States
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3
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Chen Y, Liu C, Su W, Hu Q, Zhang C, Liu H, Yin H. Identification of volatile organic compound emissions from anthropogenic and biogenic sources based on satellite observation of formaldehyde and glyoxal. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 859:159997. [PMID: 36368395 DOI: 10.1016/j.scitotenv.2022.159997] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 10/09/2022] [Accepted: 11/02/2022] [Indexed: 06/16/2023]
Abstract
Anthropogenic volatile organic compounds (VOCs) are serious pollutants in the atmosphere because of their toxicity and as precursors of secondary organic aerosols and ozone pollution. Although in-situ measurements provide accurate information on VOCs, their spatial coverage is limited and insufficient. In this study, we provide a global perspective for identifying anthropogenic VOC emission sources through the ratio of glyoxal to formaldehyde (RGF) based on satellite observations. We assessed typical cities and polluted areas in the mid latitudes and found that some Asian cities had higher anthropogenic VOC emissions than cities in Europe and America. For heavily polluted areas, such as the Yangtze River Delta (YRD), the areas dominated by anthropogenic VOCs accounted for 23 % of the total study areas. During the COVID-19 pandemic, a significant decline in RGF values was observed in the YRD and western United States, corresponding to a reduction in anthropogenic VOC emissions. Furthermore, developing countries appeared to have higher anthropogenic VOC emissions than developed countries. These observations could contribute to optimising industrial structures and setting stricter pollution standards to reduce anthropogenic VOCs in developing countries.
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Affiliation(s)
- Yujia Chen
- Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
| | - Cheng Liu
- Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China; Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China; Centre for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei 230026, China; Anhui Province Key Laboratory of Polar Environment and Global Change, University of Science and Technology of China, Hefei 230026, China.
| | - Wenjing Su
- Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China; Key Laboratory of Atmospheric Chemistry, China Meteorological Administration, Beijing 100089, China.
| | - Qihou Hu
- Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
| | - Chengxin Zhang
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Haoran Liu
- Institute of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Hao Yin
- Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
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4
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Dominutti PA, Hopkins JR, Shaw M, Mills GP, Le HA, Huy DH, Forster GL, Keita S, Hien TT, Oram DE. Evaluating major anthropogenic VOC emission sources in densely populated Vietnamese cities. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 318:120927. [PMID: 36565909 DOI: 10.1016/j.envpol.2022.120927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
Volatile organic compounds (VOCs) play an important role in urban air pollution, both as primary pollutants and through their contribution to the formation of secondary pollutants, such as tropospheric ozone and secondary organic aerosols. In this study, more than 30 VOC species were continuously monitored in the two most populous cities in Vietnam, namely Ho Chi Minh City (HCMC, September-October 2018 and March 2019) and Hanoi (March 2019). In parallel with ambient VOC sampling, grab sampling was used to target the most prevalent regional-specific emission sources and estimate their emission factors (EFs). Emission ratios (ERs) obtained from ambient sampling were compared between Vietnamese cities and other cities across the globe. No significant differences were observed between HCMC and Hanoi, suggesting the presence of similar sources. Moreover, a good global agreement was obtained in the spatial comparison within a factor of 2, with greater ER for aromatics and pentanes obtained in the Vietnamese cities. The detailed analysis of sources included the evaluation of EF from passenger cars, buses, trucks, motorcycles, 3-wheeled motorcycles, waste burning, and coal-burning emissions. Our comparisons between ambient and near-source concentration profiles show that road transport sources are the main contributors to VOC concentrations in Vietnamese cities. VOC emissions were calculated from measured EF and consumption data available in Hanoi and compared with those estimated by a global emission inventory (EDGAR v4.3.2). The total VOC emissions from the road transport sector estimated by the inventory do not agree with those calculated from our observations which showed higher total emissions by a factor of 3. Furthermore, the inventory misrepresented the VOCs speciation, mainly for isoprene, monoterpenes, aromatics, and oxygenated compounds. Accounting for these differences in regional air quality models would lead to improved predictions of their impacts and help to prioritise pollution reduction strategies in the region.
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Affiliation(s)
- Pamela A Dominutti
- Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York, YO10 5DD, United Kingdom.
| | - James R Hopkins
- Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York, YO10 5DD, United Kingdom; National Centre for Atmospheric Science, University of York, York, YO10 5DD, UK
| | - Marvin Shaw
- Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York, YO10 5DD, United Kingdom; National Centre for Atmospheric Science, University of York, York, YO10 5DD, UK
| | - Graham P Mills
- Centre for Ocean and Atmospheric Science, School of Environmental Sciences, University of East Anglia, Norwich, UK
| | - Hoang Anh Le
- Faculty of Environmental Sciences, University of Science, Vietnam National University, Hanoi, Viet Nam
| | - Duong Huu Huy
- Faculty of Food Science and Technology, Ho Chi Minh City University of Food Industry, Ho Chi Minh, Viet Nam
| | - Grant L Forster
- Centre for Ocean and Atmospheric Science, School of Environmental Sciences, University of East Anglia, Norwich, UK; National Centre for Atmospheric Science, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
| | - Sekou Keita
- Département Mathématiques-Physique-Chimie, Université Peleforo Gon Coulibaly, BP 1328 Korhogo, Cote d'Ivoire
| | - To Thi Hien
- Faculty of Environment, University of Science, Ho Chi Minh, Viet Nam; Vietnam National University, Ho Chi Minh, Viet Nam
| | - David E Oram
- Centre for Ocean and Atmospheric Science, School of Environmental Sciences, University of East Anglia, Norwich, UK; National Centre for Atmospheric Science, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
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5
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Zhao Y, Tkacik DS, May AA, Donahue NM, Robinson AL. Mobile Sources Are Still an Important Source of Secondary Organic Aerosol and Fine Particulate Matter in the Los Angeles Region. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:15328-15336. [PMID: 36215417 DOI: 10.1021/acs.est.2c03317] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Secondary organic aerosol (SOA) is a significant component of atmospheric fine particulate matter. Mobile sources have historically been a major source of SOA precursors in urban environments, but decades of regulations have reduced their emissions. Less regulated sources, such as volatile chemical products (VCPs), are of growing importance. We analyzed ambient and emissions data to assess the contribution of mobile sources to SOA formation in Los Angeles during the period of 2009-2019. During this period, air quality in the Los Angeles region has improved, but organic aerosol (OA) concentrations did not decrease as much as primary pollutants. This appears to be largely due to SOA, whose mass fraction in OA increased over this period. In 2010, about half of the freshly formed SOA measured in Pasadena, CA appears to be formed from hydrocarbon (non-oxygenated) precursors. Chemical mass balance analysis indicates that these hydrocarbon SOA precursors (including intermediate volatility organic compounds) can largely be explained by emissions from mobile sources in 2010. Our analysis indicates that continued reduction in emissions from mobile sources should lead to additional significant decreases in atmospheric SOA and PM2.5 mass in the Los Angeles region.
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Affiliation(s)
- Yunliang Zhao
- Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Daniel S Tkacik
- Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Andrew A May
- Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Neil M Donahue
- Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Allen L Robinson
- Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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6
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Shrestha S, Yoon S, Erickson MH, Guo F, Mehra M, Bui AAT, Schulze BC, Kotsakis A, Daube C, Herndon SC, Yacovitch TI, Alvarez S, Flynn JH, Griffin RJ, Cobb GP, Usenko S, Sheesley RJ. Traffic, transport, and vegetation drive VOC concentrations in a major urban area in Texas. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:155861. [PMID: 35568171 DOI: 10.1016/j.scitotenv.2022.155861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 05/06/2022] [Accepted: 05/07/2022] [Indexed: 06/15/2023]
Abstract
The population of Texas has increased rapidly in the past decade. The San Antonio Field Study (SAFS) was designed to investigate ozone (O3) production and precursors in this rapidly changing, sprawling metropolitan area. There are still many questions regarding the sources and chemistry of volatile organic compounds (VOCs) in urban areas like San Antonio which are affected by a complex mixture of industry, traffic, biogenic sources and transported pollutants. The goal of the SAFS campaign in May 2017 was to measure inorganic trace gases, VOCs, methane (CH4), and ethane (C2H6). The SAFS field design included two sites to better assess air quality across the metro area: an urban site (Traveler's World; TW) and a downwind/suburban site (University of Texas at San Antonio; UTSA). The results indicated that acetone (2.52 ± 1.17 and 2.39 ± 1.27 ppbv), acetaldehyde (1.45 ± 1.02 and 0.93 ± 0.45 ppbv) and isoprene (0.64 ± 0.49 and 1.21 ± 0.85 ppbv; TW and UTSA, respectively) were the VOCs with the highest concentrations. Additionally, positive matrix factorization showed three dominant factors of VOC emissions: biogenic, aged urban mixed source, and acetone. Methyl vinyl ketone and methacrolein (MVK + MACR) exhibited contributions from both secondary photooxidation of isoprene and direct emissions from traffic. The C2H6:CH4 demonstrated potential influence of oil and gas activities in San Antonio. Moreover, the high O3 days during the campaign were in the NOx-limited O3 formation regime and were preceded by evening peaks in select VOCs, NOx and CO. Overall, quantification of the concentration and trends of VOCs and trace gases in a major city in Texas offers vital information for general air quality management and supports strategies for reducing O3 pollution. The SAFS campaign VOC results will also add to the growing body of literature on urban sources and concentrations of VOCs in major urban areas.
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Affiliation(s)
- Sujan Shrestha
- Department of Environmental Science, Baylor University, Waco, TX, USA
| | - Subin Yoon
- Department of Environmental Science, Baylor University, Waco, TX, USA; Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USA
| | - Matthew H Erickson
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USA; TerraGraphics Environmental Engineering, Pasco, WA, USA
| | - Fangzhou Guo
- Department of Civil and Environmental Engineering, Rice University, TX, USA
| | - Manisha Mehra
- Department of Environmental Science, Baylor University, Waco, TX, USA
| | - Alexander A T Bui
- Department of Civil and Environmental Engineering, Rice University, TX, USA
| | - Benjamin C Schulze
- Department of Civil and Environmental Engineering, Rice University, TX, USA; Department of Environmental Science and Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Alexander Kotsakis
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USA; Universities Space Research Association, NASA/GSFC, Columbia, MD, USA
| | | | | | | | - Sergio Alvarez
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USA
| | - James H Flynn
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USA
| | - Robert J Griffin
- Department of Civil and Environmental Engineering, Rice University, TX, USA
| | - George P Cobb
- Department of Environmental Science, Baylor University, Waco, TX, USA
| | - Sascha Usenko
- Department of Environmental Science, Baylor University, Waco, TX, USA
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7
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Perdigones BC, Lee S, Cohen RC, Park JH, Min KE. Two Decades of Changes in Summertime Ozone Production in California's South Coast Air Basin. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:10586-10595. [PMID: 35855520 DOI: 10.1021/acs.est.2c01026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Tropospheric ozone (O3) continues to be a threat to human health and agricultural productivity. While O3 control is challenging, tracking underlying formation mechanisms provides insights for regulatory directions. Here, we describe a comprehensive analysis of the effects of changing emissions on O3 formation mechanisms with observational evidence. We present a new approach that provides a quantitative metric for the ozone production rate (OPR) and its sensitivity to precursor levels by interpreting two decades of in situ observations of the six criteria air pollutants(2001-2018). Applying to the South Coast Air Basin (SoCAB), California, we show that by 2016-2018, the basin was at the transition region between nitrogen oxide (NOx)-limited and volatile organic compound (VOC)-limited chemical regimes. Assuming future weather conditions are similar to 2016-2018, we predict that NOx-focused reduction is required to reduce the number of summer days the SoCAB is in violation of the National Ambient Air Quality Standard (70 ppbv) for O3. Roughly, ∼40% (∼60%) NOx reductions are required to reduce the OPR by ∼1.8 ppb/h (∼3.3 ppb/h). This change would reduce the number of violation days from 28 to 20% (10%) in a year, mostly in summertime. Concurrent VOC reductions which reduce the production rate of HOx radicals would also be beneficial.
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Affiliation(s)
- Begie C Perdigones
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Soojin Lee
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Ronald C Cohen
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Department of Earth and Planetary Science, University of California, Berkeley, California 94720, United States
| | - Jeong-Hoo Park
- Climate and Air Quality Research Department, National Institute of Environmental Research, Incheon 22689, Korea
| | - Kyung-Eun Min
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
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8
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Abstract
The past 60 years have seen large reductions in vehicle emissions of particulate matter (PM), nitrogen oxides (NOx), carbon monoxide (CO), hydrocarbons (HCs), sulfur dioxide (SO2), and lead (Pb). Advanced emission after-treatment technologies have been developed for gasoline and diesel vehicles to meet increasingly stringent regulations, yielding absolute emission reductions from the on-road fleet despite increased vehicle miles traveled. As a result of reduced emissions from vehicles and other sources, the air quality in cities across the U.S. and Europe has improved greatly. Turn-over of the on-road fleet, increasingly stringent emission regulations (such as Tier 3 in the U.S., LEV III in California, Euro 6 in Europe, and upcoming rules in these same regions), and the large-scale introduction of electric vehicles will lead to even lower vehicle emissions and further improvements in air quality. We review historical vehicle emissions and air quality trends and discuss the future outlook.
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9
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Tao Y, VandenBoer TC, Veres PR, Warneke C, de Gouw JA, Weber RJ, Markovic MZ, Zhao Y, Baker KR, Kelly JT, Murphy JG, Young CJ, Roberts JM. Hydrogen chloride (HCl) at ground sites during CalNex 2010 and insight into its thermodynamic properties. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2022; 127:1-16. [PMID: 35586832 PMCID: PMC9109133 DOI: 10.1029/2021jd036062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 04/07/2022] [Indexed: 06/15/2023]
Abstract
Gas phase hydrogen chloride (HCl) was measured at Pasadena and San Joaquin Valley (SJV) ground sites in California during May and June 2010 as part of the CalNex study. Observed mixing ratios were on average 0.83 ppbv at Pasadena, ranging from below detection limit (0.055 ppbv) to 5.95 ppbv, and were on average 0.084 ppbv at SJV with a maximum value of 0.776 ppbv. At both sites, HCl levels were highest during midday and shared similar diurnal variations with HNO3. Coupled phase partitioning behavior was found between HCl/Cl- and HNO3/NO3 - using thermodynamic modelling and observations. Regional modeling of Cl- and HCl using CMAQ captures some of the observed relationships but underestimates measurements by a factor of 5 or more. Chloride in the 2.5-10 μm size range in Pasadena was sometimes higher than sea salt abundances, based on co-measured Na+, implying that sources other than sea salt are important. The acid-displacement of HCl/Cl- by HNO3/NO3 - (phase partitioning of semi-volatile acids) observed at the SJV site can only be explained by aqueous phase reaction despite low RH conditions and suggests the temperature dependence of HCl phase partitioning behavior was strongly impacted by the activity coefficient changes under relevant aerosol conditions (e.g., high ionic strength). Despite the influence from activity coefficients, the gas-particle system was found to be well constrained by other stronger buffers and charge balance so that HCl and Cl- concentrations were reproduced well by thermodynamic models.
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Affiliation(s)
- Ye Tao
- Department of Chemistry, York University, Toronto, Ontario, Canada
| | | | - Patrick R. Veres
- Chemical Sciences Laboratory, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA
| | - Carsten Warneke
- Chemical Sciences Laboratory, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA
| | - Joost A. de Gouw
- Cooperative Institute for Research in the Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado, USA
| | - Rodney J. Weber
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Milos Z. Markovic
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
- Now at Picarro Inc., Santa Clara, California, USA
| | - Yongjing Zhao
- Air Quality Research Center, University of California, Davis, Davis, California, USA
| | - Kirk R. Baker
- Office of Air Quality Planning and Standards, U.S. EPA, Research Triangle Park, North Carolina, USA
| | - James T. Kelly
- Office of Air Quality Planning and Standards, U.S. EPA, Research Triangle Park, North Carolina, USA
| | - Jennifer G. Murphy
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Cora J. Young
- Department of Chemistry, York University, Toronto, Ontario, Canada
| | - James M. Roberts
- Chemical Sciences Laboratory, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA
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10
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Lopez-Coto I, Ren X, Karion A, McKain K, Sweeney C, Dickerson RR, McDonald BC, Ahn DY, Salawitch RJ, He H, Shepson PB, Whetstone JR. Carbon Monoxide Emissions from the Washington, DC, and Baltimore Metropolitan Area: Recent Trend and COVID-19 Anomaly. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:2172-2180. [PMID: 35080873 DOI: 10.1021/acs.est.1c06288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We analyze airborne measurements of atmospheric CO concentration from 70 flights conducted over six years (2015-2020) using an inverse model to quantify the CO emissions from the Washington, DC, and Baltimore metropolitan areas. We found that CO emissions have been declining in the area at a rate of ≈-4.5 % a-1 since 2015 or ≈-3.1 % a-1 since 2016. In addition, we found that CO emissions show a "Sunday" effect, with emissions being lower, on average, than for the rest of the week and that the seasonal cycle is no larger than 16 %. Our results also show that the trend derived from the NEI agrees well with the observed trend, but that NEI daytime-adjusted emissions are ≈50 % larger than our estimated emissions. In 2020, measurements collected during the shutdown in activity related to the COVID-19 pandemic indicate a significant drop in CO emissions of 16 % relative to the expected emissions trend from the previous years, or 23 % relative to the mean of 2016 to February 2020. Our results also indicate a larger reduction in April than in May. Last, we show that this reduction in CO emissions was driven mainly by a reduction in traffic.
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Affiliation(s)
- Israel Lopez-Coto
- National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
- School of Marine and Atmospheric Sciences, Stony Brook University, 100 Nicolls Road, Stony Brook, New York 11794, United States
| | - Xinrong Ren
- Department of Atmospheric and Oceanic Science, University of Maryland, 4254 Stadium Drive, College Park, Maryland 20742, United States
- Air Resources Laboratory, NOAA, 5830 University Research Court, College Park, Maryland 20740, United States
| | - Anna Karion
- National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Kathryn McKain
- NOAA Earth System Research Laboratory, Global Monitoring Laboratory, 325 Broadway, Boulder, Colorado 80305, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
| | - Colm Sweeney
- NOAA Earth System Research Laboratory, Global Monitoring Laboratory, 325 Broadway, Boulder, Colorado 80305, United States
| | - Russell R Dickerson
- Department of Atmospheric and Oceanic Science, University of Maryland, 4254 Stadium Drive, College Park, Maryland 20742, United States
| | - Brian C McDonald
- NOAA Earth System Research Laboratory, Chemical Sciences Laboratory, 325 Broadway, Boulder, Colorado 80305, United States
| | - Doyeon Y Ahn
- Department of Atmospheric and Oceanic Science, University of Maryland, 4254 Stadium Drive, College Park, Maryland 20742, United States
| | - Ross J Salawitch
- Department of Atmospheric and Oceanic Science, University of Maryland, 4254 Stadium Drive, College Park, Maryland 20742, United States
| | - Hao He
- Department of Atmospheric and Oceanic Science, University of Maryland, 4254 Stadium Drive, College Park, Maryland 20742, United States
| | - Paul B Shepson
- School of Marine and Atmospheric Sciences, Stony Brook University, 100 Nicolls Road, Stony Brook, New York 11794, United States
- Department of Chemistry, Purdue University, 610 Purdue Mall, West Lafayette, Indiana 47907, United States
| | - James R Whetstone
- National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
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11
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Pye HOT, Appel KW, Seltzer KM, Ward-Caviness CK, Murphy BN. Human-health impacts of controlling secondary air pollution precursors. ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS 2022; 9:96-101. [PMID: 35342772 PMCID: PMC8942014 DOI: 10.1021/acs.estlett.1c00798] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Exposure to ozone and fine particle (PM2.5) air pollution results in premature death. These pollutants are predominantly secondary in nature and can form from nitrogen oxides (NOX), sulfur oxides (SOX), and volatile organic compounds (VOCs). Predicted health benefits for emission reduction scenarios often incompletely account for VOCs as precursors as well as the secondary organic aerosol (SOA) component of PM2.5. Here, we show that anthropogenic VOC emission reductions are more than twice as effective as equivalent fractional reductions of SOX or NOX at reducing air pollution-associated cardiorespiratory mortality in the United States. A 25% reduction in anthropogenic VOC emissions from 2016 levels is predicted to avoid 13,000 premature deaths per year, and most (85%) of the VOC-reduction benefits result from reduced SOA with the remainder from ozone. While NOX (-5.7 ± 0.2 % yr-1) and SOX (-12 ± 1 % yr-1) emissions have declined precipitously across the U.S. since 2002, anthropogenic VOC emissions (-1.8 ± 0.3 % yr-1) and concentrations of non-methane organic carbon (-2.4 ± 1.0 % yr-1) have changed less. This work indicates preferentially controlling VOCs could yield significant benefits to human health.
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Affiliation(s)
- Havala O. T. Pye
- Office of Research and Development, U.S. Environmental Protection Agency, 109 TW Alexander Dr, Research Triangle Park, NC, 27711, USA
| | - K. Wyat Appel
- Office of Research and Development, U.S. Environmental Protection Agency, 109 TW Alexander Dr, Research Triangle Park, NC, 27711, USA
| | - Karl M. Seltzer
- Oak Ridge Institute for Science and Education Postdoctoral Fellow in the Office of Research and Development, U.S. Environmental Protection Agency, 109 TW Alexander Dr, Research Triangle Park, NC, 27711, USA
| | - Cavin K. Ward-Caviness
- Office of Research and Development, U.S. Environmental Protection Agency, 104 Mason Farm Rd, Chapel Hill, NC, 27514, USA
| | - Benjamin N. Murphy
- Office of Research and Development, U.S. Environmental Protection Agency, 109 TW Alexander Dr, Research Triangle Park, NC, 27711, USA
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12
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Liang Y, Weber RJ, Misztal PK, Jen CN, Goldstein AH. Aging of Volatile Organic Compounds in October 2017 Northern California Wildfire Plumes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:1557-1567. [PMID: 35037463 DOI: 10.1021/acs.est.1c05684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In the western United States, the number and severity of large wildfires have been growing for decades. Biomass burning (BB) is a major source of volatile organic compounds (VOCs) to the atmosphere both globally and regionally. Following emission, BB VOCs are oxidized while being transported downwind, producing ozone, secondary organic aerosols, and secondary hazardous VOCs. In this research, we measured VOCs using proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS) in an urban area 55-65 km downwind of the October 2017 Northern California wildfires. Nonaromatic oxygenated compounds were the dominant component of BB VOCs measured. In the smoke plumes, the VOCs account for 70-75% of the total observed organic carbon, with the remainder being particulate matter (with a diameter of <2.5 μm, PM2.5). We show that the correlation of VOCs with furan (primary BB VOC) and maleic anhydride (secondary BB VOC) can indicate the origin of the VOCs. This was further confirmed by the diurnal variations of the VOCs and their concentration-weighted trajectories. Oxidation during transport consumed highly reactive compounds including benzenoids, furanoids, and terpenoids and produced more oxygenated VOCs. Furthermore, wildfire VOCs altered the ozone formation regime and raised the O3 levels in the San Francisco Bay Area.
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Affiliation(s)
- Yutong Liang
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California 94720, United States
| | - Robert J Weber
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California 94720, United States
| | - Pawel K Misztal
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California 94720, United States
- Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Coty N Jen
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California 94720, United States
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United State
| | - Allen H Goldstein
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California 94720, United States
- Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, California 94720, United States
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13
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Hurley JF, Smiley E, Isaacman-VanWertz G. Modeled Emission of Hydroxyl and Ozone Reactivity from Evaporation of Fragrance Mixtures. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:15672-15679. [PMID: 34784200 DOI: 10.1021/acs.est.1c04004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Volatile chemical products (VCPs) account for increasing fractions of organic carbon emitted to the atmosphere, particularly in urban areas. Fragrances are potentially reactive components that are added to many VCPs. To better constrain these emissions, 11 commercially available liquid fragrance mixtures were characterized for their composition and their evaporation modeled. Emissions of mass, hydroxyl reactivity, and ozone reactivity were estimated by modeling under four different scenarios. Fragrance compounds were generally less than one-half the mass of fragrance mixtures, with the balance comprised of solvents and plasticizers and unresolved mass thought to be dominated by plasticizers. The results showed that terpenes and terpenoids account for nearly all of the emitted mass and reactivity while only comprising ∼10% w/w on average of the liquid fragrance mixtures. Most of the reactivity is emitted within hours, with ozone reactivity evolving more rapidly than OH reactivity and comprised almost entirely of terpenes. Limonene, a common fragrance constituent, dominates the reactivity of emitted carbon. Generally, 20-40% of the potential hydroxyl reactivity contained in the fragrance mixture does not evaporate on time scales sufficient to have an impact on local or regional air quality.
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Affiliation(s)
- James F Hurley
- Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Elizabeth Smiley
- Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Gabriel Isaacman-VanWertz
- Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
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14
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Gu S, Guenther A, Faiola C. Effects of Anthropogenic and Biogenic Volatile Organic Compounds on Los Angeles Air Quality. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:12191-12201. [PMID: 34495669 DOI: 10.1021/acs.est.1c01481] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Assessing the role of volatile organic compounds (VOCs) in production of ozone and secondary organic aerosol (SOA) is especially important in light of ongoing policy goals. Here, we estimated the ozone formation potential (OFP) and SOA formation potential (SOAP) of anthropogenic and biogenic VOC emissions to evaluate (1) anthropogenic VOCs and associated sectors that dominate OFP and SOAP and (2) the potential impacts of enhanced biogenic VOCs from urban greening programs on air quality in Los Angeles county. In the present-day scenario, ethylene had the largest OFP followed by m & p-xylene, toluene, propylene, and formaldehyde. The top five contributors to SOAP were toluene, mineral spirits, benzene, heptadecane, and hexadecane. Mobile and solvent sources were the dominant VOC sources for both OFP and SOAP. The potential increases in biogenic VOC emissions due to future urban greening had significant effects on urban air quality that offset the benefits of reducing anthropogenic VOC emissions. This study demonstrates that urban greening programs in Los Angeles county, and likely other cities as well, need to account for both anthropogenic and biogenic VOC contributions to secondary pollution, and greening cities should consider using vegetation types with low VOC emissions to avoid further degradation to urban air quality.
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Affiliation(s)
- Shan Gu
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, California 92697, United States
| | - Alex Guenther
- Department of Earth System Science, University of California Irvine, Irvine, California 92697, United States
| | - Celia Faiola
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, California 92697, United States
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
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15
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Shao M, Wang W, Yuan B, Parrish DD, Li X, Lu K, Wu L, Wang X, Mo Z, Yang S, Peng Y, Kuang Y, Chen W, Hu M, Zeng L, Su H, Cheng Y, Zheng J, Zhang Y. Quantifying the role of PM 2.5 dropping in variations of ground-level ozone: Inter-comparison between Beijing and Los Angeles. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 788:147712. [PMID: 34134364 DOI: 10.1016/j.scitotenv.2021.147712] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/13/2021] [Accepted: 05/09/2021] [Indexed: 06/12/2023]
Abstract
In recent decade the ambient fine particle (PM2.5) levels have shown a trend of distinct dropping in China, while ground-level ozone concentrations have been increasing in Beijing and many other Chinese mega-cities. The variation pattern in Los Angeles was markedly different, with PM2.5 and ozone decreasing together over past decades. In this study, we utilize observation-based methods to establish the parametric relationship between PM2.5 concentration and key aerosol physical properties (including aerosol optical depth and aerosol surface concentration), and an observation-based 1-D photochemical model to quantify the response of PM2.5 decline in enhancing ground-level ozone pollution over a large PM2.5 concentration range (10-120 μg m-3). We find that the significance of ozone enhancement due to PM2.5 dropping depends on both the PM2.5 levels and optical properties of particles. Ozone formation increased by 37% in 2006-2016 due to PM2.5 dropping in Beijing, while it becomes less important (7%) as PM2.5 reaches below 40 μg/m3, similar to Los Angeles since 1980s. Therefore, the two cities show the convergence of air pollutant characteristics. Hence a control strategy prioritizing reactive volatile organic compound abatement is projected to yield simultaneous ozone and PM2.5 reductions in Beijing, as experienced in Los Angeles.
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Affiliation(s)
- Min Shao
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou, China; College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Wenjie Wang
- College of Environmental Sciences and Engineering, Peking University, Beijing, China; Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
| | - Bin Yuan
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou, China.
| | - David D Parrish
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou, China
| | - Xin Li
- College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Keding Lu
- College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Luolin Wu
- School of Atmospheric Sciences, Sun Yat-sen University, Guangzhou, China
| | - Xuemei Wang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou, China.
| | - Ziwei Mo
- School of Atmospheric Sciences, Sun Yat-sen University, Guangzhou, China
| | - Suxia Yang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou, China
| | - Yuwen Peng
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou, China
| | - Ye Kuang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou, China
| | - Weihua Chen
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou, China
| | - Min Hu
- College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Limin Zeng
- College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Hang Su
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
| | - Yafang Cheng
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany; Minerva Research Group, Max Planck Institute for Chemistry, Mainz, Germany
| | - Junyu Zheng
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou, China
| | - Yuanhang Zhang
- College of Environmental Sciences and Engineering, Peking University, Beijing, China
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16
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Volatile chemical product emissions enhance ozone and modulate urban chemistry. Proc Natl Acad Sci U S A 2021; 118:2026653118. [PMID: 34341119 DOI: 10.1073/pnas.2026653118] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Decades of air quality improvements have substantially reduced the motor vehicle emissions of volatile organic compounds (VOCs). Today, volatile chemical products (VCPs) are responsible for half of the petrochemical VOCs emitted in major urban areas. We show that VCP emissions are ubiquitous in US and European cities and scale with population density. We report significant VCP emissions for New York City (NYC), including a monoterpene flux of 14.7 to 24.4 kg ⋅ d-1 ⋅ km-2 from fragranced VCPs and other anthropogenic sources, which is comparable to that of a summertime forest. Photochemical modeling of an extreme heat event, with ozone well in excess of US standards, illustrates the significant impact of VCPs on air quality. In the most populated regions of NYC, ozone was sensitive to anthropogenic VOCs (AVOCs), even in the presence of biogenic sources. Within this VOC-sensitive regime, AVOCs contributed upwards of ∼20 ppb to maximum 8-h average ozone. VCPs accounted for more than 50% of this total AVOC contribution. Emissions from fragranced VCPs, including personal care and cleaning products, account for at least 50% of the ozone attributed to VCPs. We show that model simulations of ozone depend foremost on the magnitude of VCP emissions and that the addition of oxygenated VCP chemistry impacts simulations of key atmospheric oxidation products. NYC is a case study for developed megacities, and the impacts of VCPs on local ozone are likely similar for other major urban regions across North America or Europe.
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17
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Hallar AG, Brown SS, Crosman E, Barsanti K, Cappa CD, Faloona I, Fast J, Holmes HA, Horel J, Lin J, Middlebrook A, Mitchell L, Murphy J, Womack CC, Aneja V, Baasandorj M, Bahreini R, Banta R, Bray C, Brewer A, Caulton D, de Gouw J, De Wekker SF, Farmer DK, Gaston CJ, Hoch S, Hopkins F, Karle NN, Kelly JT, Kelly K, Lareau N, Lu K, Mauldin RL, Mallia DV, Martin R, Mendoza D, Oldroyd HJ, Pichugina Y, Pratt KA, Saide P, Silva PJ, Simpson W, Stephens BB, Stutz J, Sullivan A. Coupled Air Quality and Boundary-Layer Meteorology in Western U.S. Basins during Winter: Design and Rationale for a Comprehensive Study. BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY 2021; 0:1-94. [PMID: 34446943 PMCID: PMC8384125 DOI: 10.1175/bams-d-20-0017.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Wintertime episodes of high aerosol concentrations occur frequently in urban and agricultural basins and valleys worldwide. These episodes often arise following development of persistent cold-air pools (PCAPs) that limit mixing and modify chemistry. While field campaigns targeting either basin meteorology or wintertime pollution chemistry have been conducted, coupling between interconnected chemical and meteorological processes remains an insufficiently studied research area. Gaps in understanding the coupled chemical-meteorological interactions that drive high pollution events make identification of the most effective air-basin specific emission control strategies challenging. To address this, a September 2019 workshop occurred with the goal of planning a future research campaign to investigate air quality in Western U.S. basins. Approximately 120 people participated, representing 50 institutions and 5 countries. Workshop participants outlined the rationale and design for a comprehensive wintertime study that would couple atmospheric chemistry and boundary-layer and complex-terrain meteorology within western U.S. basins. Participants concluded the study should focus on two regions with contrasting aerosol chemistry: three populated valleys within Utah (Salt Lake, Utah, and Cache Valleys) and the San Joaquin Valley in California. This paper describes the scientific rationale for a campaign that will acquire chemical and meteorological datasets using airborne platforms with extensive range, coupled to surface-based measurements focusing on sampling within the near-surface boundary layer, and transport and mixing processes within this layer, with high vertical resolution at a number of representative sites. No prior wintertime basin-focused campaign has provided the breadth of observations necessary to characterize the meteorological-chemical linkages outlined here, nor to validate complex processes within coupled atmosphere-chemistry models.
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Affiliation(s)
| | | | - Erik Crosman
- Department of Life, Earth, and Environmental Sciences, West Texas A&M University
| | - Kelley Barsanti
- Department of Chemical and Environmental Engineering, Center for Environmental Research and Technology, University of California, Riverside
| | - Christopher D. Cappa
- Department of Civil and Environmental Engineering, University of California, Davis 95616 USA
| | - Ian Faloona
- Department of Land, Air and Water Resources, University of California, Davis
| | - Jerome Fast
- Atmospheric Science and Global Change Division, Pacific Northwest, National Laboratory, Richland, Washington, USA
| | - Heather A. Holmes
- Department of Chemical Engineering, University of Utah, Salt Lake City, UT
| | - John Horel
- Department of Atmospheric Sciences, University of Utah, Salt Lake City, UT
| | - John Lin
- Department of Atmospheric Sciences, University of Utah, Salt Lake City, UT
| | | | - Logan Mitchell
- Department of Atmospheric Sciences, University of Utah, Salt Lake City, UT
| | - Jennifer Murphy
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Caroline C. Womack
- Cooperative Institute for Research in Environmental Sciences, University of Colorado/ NOAA Chemical Sciences Laboratory, Boulder, CO
| | - Viney Aneja
- Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University
| | | | - Roya Bahreini
- Environmental Sciences, University of California, Riverside, CA
| | | | - Casey Bray
- Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University
| | - Alan Brewer
- NOAA Chemical Sciences Laboratory, Boulder, CO
| | - Dana Caulton
- Department of Atmospheric Science, University of Wyoming
| | - Joost de Gouw
- Cooperative Institute for Research in Environmental Sciences & Department of Chemistry, University of Colorado, Boulder, CO
| | | | | | - Cassandra J. Gaston
- Department of Atmospheric Science - Rosenstiel School of Marine and Atmospheric Science, University of Miami
| | - Sebastian Hoch
- Department of Atmospheric Sciences, University of Utah, Salt Lake City, UT
| | | | - Nakul N. Karle
- Environmental Science and Engineering, The University of Texas at El Paso, TX
| | - James T. Kelly
- Office of Air Quality Planning and Standards, US Environmental Protection Agency, Research Triangle Park, NC
| | - Kerry Kelly
- Chemical Engineering, University of Utah, Salt Lake City, UT
| | - Neil Lareau
- Atmospheric Sciences and Environmental Sciences and Health, University of Nevada, Reno, NV
| | - Keding Lu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Science and Engineering, Peking University, Beijing, China, 100871
| | - Roy L. Mauldin
- National Center for Atmospheric Research, Boulder, CO 80307, USA
| | - Derek V. Mallia
- Department of Atmospheric Sciences, University of Utah, Salt Lake City, UT
| | - Randal Martin
- Civil and Environmental Engineering, Utah State University, Utah Water Research Laboratory, Logan, UT
| | - Daniel Mendoza
- Department of Atmospheric Sciences, University of Utah, Salt Lake City, UT
| | - Holly J. Oldroyd
- Department of Civil and Environmental Engineering, University of California, Davis
| | | | | | - Pablo Saide
- Department of Atmospheric and Oceanic Sciences, and Institute of the Environment and Sustainability, University of California, Los Angeles
| | - Phillip J. Silva
- Food Animal Environmental Systems Research Unit, USDA-ARS, Bowling Green, KY
| | - William Simpson
- Department of Chemistry, Biochemistry, and Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775-6160
| | - Britton B. Stephens
- Earth Observing Laboratory, National Center for Atmospheric Research, Boulder, CO
| | - Jochen Stutz
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles
| | - Amy Sullivan
- Department of Atmospheric Science, Colorado State University, Fort Collins, CO
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18
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Drozd GT, Weber RJ, Goldstein AH. Highly Resolved Composition during Diesel Evaporation with Modeled Ozone and Secondary Aerosol Formation: Insights into Pollutant Formation from Evaporative Intermediate Volatility Organic Compound Sources. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:5742-5751. [PMID: 33861084 DOI: 10.1021/acs.est.0c08832] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
As stricter regulations continue to reduce vehicular emissions, other emission sources such as evaporative emissions from road building and volatile consumer products have become more important in overall pollutant forming emissions in many urban areas. Emission regulations have historically targeted volatile organic compounds (VOCs) to reduce ozone, but intermediate volatility organic compounds (IVOCs) also contribute to ozone formation and the formation of secondary organic aerosol (SOA) that often dominates fine particulate matter. Emission rates and pollutant formation from IVOCs are not well constrained in current inventories and models. This study uses diesel fuel as a representative IVOC mixture in evaporation tests performed in a wind tunnel under varying wind speeds and liquid diesel temperatures. Comprehensive composition measurements guided the development of a model to determine rates of evaporation and estimate pollutant production. Results show that reducing IVOC emissions can result in significant reductions in ozone formation, in addition to the expected reductions in SOA formation, and that IVOC emissions can continue over the course of a month. Ozone formation from IVOC emissions is equal to that from VOCs after 3 days of evaporation at 0.65 g-ozone/g-diesel released. SOA formation is dominated by IVOCs, reaching 0.2 g-SOA/g-diesel released after 30 days.
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Affiliation(s)
- Greg T Drozd
- Department of Chemistry, Colby College, Waterville, 04901 Maine, United States
| | - Robert Jay Weber
- Department of Environmental Science, Policy, and Management, University of California, Berkeley 94720-3114, California, United States
| | - Allen H Goldstein
- Department of Environmental Science, Policy, and Management, University of California, Berkeley 94720-3114, California, United States
- Department of Civil and Environmental Engineering, University of California, Berkeley 94720-3114, California, United States
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19
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Gkatzelis GI, Coggon MM, McDonald BC, Peischl J, Gilman JB, Aikin KC, Robinson MA, Canonaco F, Prevot ASH, Trainer M, Warneke C. Observations Confirm that Volatile Chemical Products Are a Major Source of Petrochemical Emissions in U.S. Cities. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:4332-4343. [PMID: 33720711 DOI: 10.1021/acs.est.0c05471] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Despite decades of declining air pollution, urban U.S. areas are still affected by summertime ozone and wintertime particulate matter exceedance events. Volatile organic compounds (VOCs) are known precursors of secondary organic aerosol (SOA) and photochemically produced ozone. Urban VOC emission sources, including on-road transportation emissions, have decreased significantly over the past few decades through successful regulatory measures. These drastic reductions in VOC emissions have led to a change in the distribution of urban emissions and noncombustion sources of VOCs such as those from volatile chemical products (VCPs), which now account for a higher fraction of the urban VOC burden. Given this shift in emission sources, it is essential to quantify the relative contribution of VCP and mobile source emissions to urban pollution. Herein, ground site and mobile laboratory measurements of VOCs were performed. Two ground site locations with different population densities, Boulder, CO, and New York City (NYC), NY, were chosen in order to evaluate the influence of VCPs in cities with varying mixtures of VCPs and mobile source emissions. Positive matrix factorization was used to attribute hundreds of compounds to mobile- and VCP-dominated sources. VCP-dominated emissions contributed to 42 and 78% of anthropogenic VOC emissions for Boulder and NYC, respectively, while mobile source emissions contributed 58 and 22%. Apportioned VOC emissions were compared to those estimated from the Fuel-based Inventory of Vehicle Emissions and VCPs and agreed to within 25% for the bulk comparison and within 30% for more than half of individual compounds. The evaluated inventory was extended to other U.S. cities and it suggests that 50 to 80% of emissions, reactivity, and the SOA-forming potential of urban anthropogenic VOCs are associated with VCP-dominated sources, demonstrating their important role in urban U.S. air quality.
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Affiliation(s)
- Georgios I Gkatzelis
- NOAA Chemical Sciences Laboratory, Boulder, Colorado 80305, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Forschungszentrum Jülich, Jülich 52425, Germany
| | - Matthew M Coggon
- NOAA Chemical Sciences Laboratory, Boulder, Colorado 80305, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Brian C McDonald
- NOAA Chemical Sciences Laboratory, Boulder, Colorado 80305, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Jeff Peischl
- NOAA Chemical Sciences Laboratory, Boulder, Colorado 80305, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Jessica B Gilman
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Kenneth C Aikin
- NOAA Chemical Sciences Laboratory, Boulder, Colorado 80305, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Michael A Robinson
- NOAA Chemical Sciences Laboratory, Boulder, Colorado 80305, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | | | - Andre S H Prevot
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen CH-5232, Switzerland
| | - Michael Trainer
- NOAA Chemical Sciences Laboratory, Boulder, Colorado 80305, United States
| | - Carsten Warneke
- NOAA Chemical Sciences Laboratory, Boulder, Colorado 80305, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
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20
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Seasonal Variations of Carbonyls and Their Contributions to the Ozone Formation in Urban Atmosphere of Taiyuan, China. ATMOSPHERE 2021. [DOI: 10.3390/atmos12040510] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ambient carbonyls are critical precursors of ozone (O3) and secondary organic aerosols (SOA). To better understand the pollution characteristics of carbonyls in Taiyuan, field samplings were conducted, and 13 carbonyls were detected in an urban site of Taiyuan for the four seasons. The total concentration of carbonyls in the atmosphere was 19.67 ± 8.56 μg/m3. Formaldehyde (7.70 ± 4.78 μg/m3), acetaldehyde (2.95 ± 1.20 μg/m3) and acetone (5.57 ± 2.41 μg/m3) were the dominant carbonyl compounds, accounting for more than 85% of the total carbonyls. The highest values for formaldehyde and acetone occurred in summer and autumn, respectively, and the lowest occurred in winter. The variations for acetaldehyde were not distinct in the four seasons. Formaldehyde and acetone levels increased obviously in the daytime and decreased at night, while acetaldehyde did not show significant diurnal variations. Higher temperature and stronger sunlight intensity could facilitate the photochemical reaction of volatile organic compounds (VOCs) and enhance the O3 levels in summer. Formaldehyde and acetaldehyde contributed 70–95% of carbonyls’ ozone formation potential (OFP) caused by carbonyls with the highest totals of 268.62 μg/m3 and 38.14 μg/m3, respectively. The highest concentrations of carbonyls from south and southwest winds in summer suggest that the coke industries in the southern Taiyuan Basin should be, firstly, controlled for the alleviation of ozone pollution.
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21
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Seltzer KM, Pennington E, Rao V, Murphy BN, Strum M, Isaacs KK, Pye HOT. Reactive organic carbon emissions from volatile chemical products. ATMOSPHERIC CHEMISTRY AND PHYSICS 2021; 21:5079-5100. [PMID: 34122530 PMCID: PMC8193795 DOI: 10.5194/acp-21-5079-2021] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Volatile chemical products (VCPs) are an increasingly important source of anthropogenic reactive organic carbon (ROC) emissions. Among these sources are everyday items, such as personal care products, general cleaners, architectural coatings, pesticides, adhesives, and printing inks. Here, we develop VCPy, a new framework to model organic emissions from VCPs throughout the United States, including spatial allocation to regional and local scales. Evaporation of a species from a VCP mixture in the VCPy framework is a function of the compound-specific physiochemical properties that govern volatilization and the timescale relevant for product evaporation. We introduce two terms to describe these processes: evaporation timescale and use timescale. Using this framework, predicted national per capita organic emissions from VCPs are 9.5 kg per person per year (6.4 kg C per person per year) for 2016, which translates to 3.05 Tg (2.06 Tg C), making VCPs a dominant source of anthropogenic organic emissions in the United States. Uncertainty associated with this framework and sensitivity to select parameters were characterized through Monte Carlo analysis, resulting in a 95 % confidence interval of national VCP emissions for 2016 of 2.61-3.53 Tg (1.76-2.38 Tg C). This nationwide total is broadly consistent with the U.S. EPA's 2017 National Emission Inventory (NEI); however, county-level and categorical estimates can differ substantially from NEI values. VCPy predicts higher VCP emissions than the NEI for approximately half of all counties, with 5 % of all counties having greater than 55 % higher emissions. Categorically, application of the VCPy framework yields higher emissions for personal care products (150 %) and paints and coatings (25 %) when compared to the NEI, whereas pesticides (-54 %) and printing inks (-13 %) feature lower emissions. An observational evaluation indicates emissions of key species from VCPs are reproduced with high fidelity using the VCPy framework (normalized mean bias of -13 % with r =0.95). Sector-wide, the effective secondary organic aerosol yield and maximum incremental reactivity of VCPs are 5.3 % by mass and 1.58 gO3 g-1, respectively, indicating VCPs are an important, and likely to date underrepresented, source of secondary pollution in urban environments.
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Affiliation(s)
- Karl M Seltzer
- Oak Ridge Institute for Science and Education Postdoctoral Fellow in the Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Elyse Pennington
- Oak Ridge Institute for Science and Education Fellow in the Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
- California Institute of Technology, Pasadena, CA 91125, USA
| | - Venkatesh Rao
- Office of Air and Radiation, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Benjamin N Murphy
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Madeleine Strum
- Office of Air and Radiation, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Kristin K Isaacs
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Havala O T Pye
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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22
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Characterizing the Performance of a Compact BTEX GC-PID for Near-Real Time Analysis and Field Deployment. SENSORS 2021; 21:s21062095. [PMID: 33802681 PMCID: PMC8002566 DOI: 10.3390/s21062095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 03/08/2021] [Accepted: 03/12/2021] [Indexed: 02/01/2023]
Abstract
In this study, we test the performance of a compact gas chromatograph with photoionization detector (GC-PID) and optimize the configuration to detect ambient (sub-ppb) levels of benzene, toluene, ethylbenzene, and xylene isomers (BTEX). The GC-PID system was designed to serve as a relatively inexpensive (~10 k USD) and field-deployable air toxic screening tool alternative to conventional benchtop GCs. The instrument uses ambient air as a carrier gas and consists of a Tenax-GR sorbent-based preconcentrator, a gas sample valve, two capillary columns, and a photoionization detector (PID) with a small footprint and low power requirement. The performance of the GC-PID has been evaluated in terms of system linearity and sensitivity in field conditions. The BTEX-GC system demonstrated the capacity to detect BTEX at levels as high as 500 ppb with a linear calibration range of 0–100 ppb. A detection limit lower than 1 ppb was found for all BTEX compounds with a sampling volume of 1 L. No significant drift in the instrument was observed. A time-varying calibration technique was established that requires minimal equipment for field operations and optimizes the sampling procedure for field measurements. With an analysis time of less than 15 min, the compact GC-PID is ideal for field deployment of background and polluted atmospheres for near-real time measurements of BTEX. The results highlight the application of the compact and easily deployable GC-PID for community monitoring and screening of air toxics.
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23
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Nussbaumer CM, Cohen RC. Impact of OA on the Temperature Dependence of PM 2.5 in the Los Angeles Basin. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:3549-3558. [PMID: 33661623 DOI: 10.1021/acs.est.0c07144] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Air quality policy in the Los Angeles megacity is a guidepost for other megacities. Over the last 2 decades, the policy has substantially reduced aerosol (OA) concentrations and the frequency of high aerosol events in the region. During this time, the emissions contributing to, and the temperature associated with, high aerosol events have changed. Early in the record, aerosol concentrations responded to a variety of different sources. We show that emission control has been effective with a strong decrease in temperature-independent sources. As a result, the response of aerosol to temperature has become a dominant feature of high aerosol events in the basin. The organic fraction of the aerosol (OA) increases with the temperature approaching 35% at 40 °C. We describe a simple conceptual model of aerosol in Los Angeles, illustrating how benzene, toluene, ethylbenzene, and xylenes (BTEX) and isoprene, along with molecules for which these are plausible surrogates such as monoterpenes, are sufficient to explain the observed temperature dependence of PM 2.5.
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Affiliation(s)
- Clara M Nussbaumer
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Ronald C Cohen
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
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24
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Nussbaumer CM, Cohen RC. The Role of Temperature and NO x in Ozone Trends in the Los Angeles Basin. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:15652-15659. [PMID: 33274926 DOI: 10.1021/acs.est.0c04910] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Ozone, a major contributor to poor air quality, has an array of adverse effects on human, animal, and plant health. In the Los Angeles basin, a megacity that has pursued cleaner air for decades, unhealthy levels of ozone have decreased but remain stubbornly frequent even as the ozone precursors NOx (nitrogen oxides ≡ NO2 + NO) and VOC (volatile organic compounds) have decreased. We describe a combined analysis of decadal trends in these precursors, differences in emissions with day-of-week, and of the impact of temperature to assess the role of VOC and NOx and the likely effects of additional emission reductions on the occurrence of high ozone in the region.
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Affiliation(s)
- Clara M Nussbaumer
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720-1460, United States
| | - Ronald C Cohen
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720-1460, United States
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25
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Heald CL, Gouw JD, Goldstein AH, Guenther AB, Hayes PL, Hu W, Isaacman-VanWertz G, Jimenez JL, Keutsch FN, Koss AR, Misztal PK, Rappenglück B, Roberts JM, Stevens PS, Washenfelder RA, Warneke C, Young CJ. Contrasting Reactive Organic Carbon Observations in the Southeast United States (SOAS) and Southern California (CalNex). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:14923-14935. [PMID: 33205951 DOI: 10.1021/acs.est.0c05027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Despite the central role of reactive organic carbon (ROC) in the formation of secondary species that impact global air quality and climate, our assessment of ROC abundance and impacts is challenged by the diversity of species that contribute to it. We revisit measurements of ROC species made during two field campaigns in the United States: the 2013 SOAS campaign in forested Centreville, AL, and the 2010 CalNex campaign in urban Pasadena, CA. We find that average measured ROC concentrations are about twice as high in Pasadena (73.8 μgCsm-3) than in Centreville (36.5 μgCsm-3). However, the OH reactivity (OHR) measured at these sites is similar (20.1 and 19.3 s-1). The shortfall in OHR when summing up measured contributions is 31%, at Pasadena and 14% at Centreville, suggesting that there may be a larger reservoir of unmeasured ROC at the former site. Estimated O3 production and SOA potential (defined as concentration × yield) are both higher during CalNex than SOAS. This analysis suggests that the ROC in urban California is less reactive, but due to higher concentrations of oxides of nitrogen and hydroxyl radicals, is more efficient in terms of O3 and SOA production, than in the forested southeastern U.S.
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Affiliation(s)
- Colette L Heald
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Joost de Gouw
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
| | - Allen H Goldstein
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720, United States
- Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720, United States
| | - Alex B Guenther
- Department of Earth System Science, University of California, Irvine,California 92697, United States
| | - Patrick L Hayes
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Weiwei Hu
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
| | - Gabriel Isaacman-VanWertz
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720, United States
| | - Jose L Jimenez
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
| | - Frank N Keutsch
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Abigail R Koss
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, United States
| | - Pawel K Misztal
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720, United States
| | - Bernhard Rappenglück
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas 77204, United States
| | - James M Roberts
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, United States
| | - Philip S Stevens
- O'Neill School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana 47405, United States
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Rebecca A Washenfelder
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, United States
| | - Carsten Warneke
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, United States
| | - Cora J Young
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
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26
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Altuwayjiri A, Pirhadi M, Taghvaee S, Sioutas C. Long-term trends in the contribution of PM 2.5 sources to organic carbon (OC) in the Los Angeles basin and the effect of PM emission regulations. Faraday Discuss 2020; 226:74-99. [PMID: 33241815 DOI: 10.1039/d0fd00074d] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This study aimed to investigate the long-term variations in the contributions of emission sources to ambient PM2.5 organic carbon (OC) in central Los Angeles (CELA) and Riverside using the Chemical Speciation Network (CSN) database in the 2005-2015 period, during which several federal and state PM-based regulations were implemented to reduce tailpipe emissions in the region. The measured concentrations of OC, OC volatility fractions (i.e., OC1, OC2, and OC3), elemental carbon (EC), ozone (O3), sulfate, the ratio of potassium ion to potassium (K+/K), and selected metal elements were used as the input to the positive matrix factorization (PMF) model. PMF resolved tailpipe emissions, non-tailpipe emissions, secondary organic aerosols (SOA), biomass burning, and local industrial activities as the main sources contributing to ambient OC at both sampling sites. Vehicular exhaust emissions, non-tailpipe emissions, and SOA were dominant sources of OC across our sampling sites, accounting cumulatively for more than 80% of total OC mass throughout the study period. Our findings showed a significant reduction in the absolute and relative contributions of tailpipe emissions to the ambient OC levels in CELA and Riverside over the time period of 2005-2015. The contribution of exhaust emissions to total OC in CELA decreased from 3.5 µg m-3 (49%) in 2005 to 1.5 µg m-3 (34%) in 2015, while similar trends were observed at Riverside during this period. These reductions are mainly attributed to the implementation of several federal, state, and local air quality regulations targeting tailpipe emissions in the area. The implementation of these regulations furthermore reduced the emissions of primary organic precursors of secondary aerosols, resulting in an overall decrease (although not statistically significant, P values ranging from 0.4 to 0.6) in SOA mass concentration in both locations over the study period. In contrast to the tailpipe emissions, we observed an increasing trend (by ∼4 to 14%) in the relative contribution of non-tailpipe emissions to OC over this time period at both sites. Our results demonstrated the effectiveness of air quality regulations in reducing direct tailpipe emissions in the area, but also underpinned the need to develop equally effective mitigation policies targeting non-tailpipe PM emissions.
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Affiliation(s)
- Abdulmalik Altuwayjiri
- University of Southern California, Department of Civil and Environmental Engineering, 3620 S. Vermont Ave. KAP210, Los Angeles, CA 90089, USA.
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27
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Bishop GA, DeFries TH, Sidebottom JA, Kemper JM. Vehicle Exhaust Remote Sensing Device Method to Screen Vehicles for Evaporative Running Loss Emissions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:14627-14634. [PMID: 33156619 DOI: 10.1021/acs.est.0c05433] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Vehicle hydrocarbon (HC) emissions can be emitted from either tailpipe or nontailpipe locations, and understanding their fleet apportionment is important for a successful air pollution policy. Vehicles initially misidentified as having elevated tailpipe HC emissions first indicated that roadside exhaust sensors could detect the presence of evaporative HC emissions as increased noise in the HC/carbon dioxide (CO2) correlation measurement. The 90th percentile of the largest residual of the HC/CO2 correlation is defined as a running loss index (RLI) for each measurement. An RLI that is three standard deviations or greater above the instrument noise indicates possible evaporative running loss emissions with the probability increasing with larger RLI values. Two databases of vehicle emission measurements previously collected in West Los Angeles in 2013 and 2015 were screened using this method. The screening estimated that 0.09% (31/33,806) and 0.18% (49/27,413) of the attempted measurements indicated evaporative running loss emissions from a 9-year-old fleet. California LEV I certified vehicles (1994-2003 model years) accounted for the largest age group for both. The minimum detection limits for the instrument used were estimated at 2.8 and 1.6 g/mile on a propane basis for the 2013 and 2015 data, respectively, or 32-56 times the Federal Tier 2 and Tier 3 standards of 0.05 g/mile.
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Affiliation(s)
- Gary A Bishop
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Timothy H DeFries
- Eastern Research Group, Inc., 3508 Far West Blvd., Suite 210, Austin, Texas 78731, United States
| | - James A Sidebottom
- Colorado Department of Public Health and Environment, 4300 Cherry Creek Drive South, Denver, Colorado 80246, United States
| | - James M Kemper
- Colorado Department of Public Health and Environment, 4300 Cherry Creek Drive South, Denver, Colorado 80246, United States
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28
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Lin N, Ding N, Meza-Wilson E, Manuradha Devasurendra A, Godwin C, Kyun Park S, Batterman S. Volatile organic compounds in feminine hygiene products sold in the US market: A survey of products and health risks. ENVIRONMENT INTERNATIONAL 2020; 144:105740. [PMID: 32866732 PMCID: PMC7958867 DOI: 10.1016/j.envint.2020.105740] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/26/2020] [Accepted: 04/13/2020] [Indexed: 05/04/2023]
Abstract
Feminine hygiene products (FHPs) are used on highly permeable and sensitive vaginal and vulvar tissues by many women. These products contain a variety of chemicals, and few regulations require disclosure of their ingredients. The objectives of this study are to identify volatile organic compounds (VOCs) that may be present in these products and to evaluate the potential for exposure and health risk associated with product use. We collected 79 commercially available FHPs, including washes, tampons, menstrual pads, wipes, sprays, powders and moisturizers, and analyzed their composition using purge and trap sampling, thermal desorption, gas chromatography and mass spectroscopy. Exposures and risks were modeled using reasonable upper bound exposure scenarios. The highest VOC concentrations (as total target VOCs) were found in washes, sprays and powders, with median concentrations from 25,000 to 34,000 ng/g. Benzene (maximum: 3,604 ng/g) was detected in 83% of the collected products, and 1,4-dioxane (maximum: 24,354 ng/g) in 50% of the products. VOC composition depended on the FHP type, manufacturer and brand. Products labeled as "organic," "natural," or "for sensitive skin" did not necessarily have lower VOC concentrations. For most FHPs, calculated risks were low; however, menstrual pads had hazard ratios of up to 11, sprays and powders had hazard ratios of up to 2.2 and excess cancer risks of up to 2.1 × 10-6, and washes had excess cancer risks of up to 3.3 × 10-6. Our data suggest that all tested FHPs contained some toxic VOCs, and that risks of using some products should be addressed. We recommend the elimination of toxic ingredients and the disclosure of all chemicals that are used in these products.
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Affiliation(s)
- Nan Lin
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ning Ding
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI 48109, USA
| | - Emily Meza-Wilson
- College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI 48109, USA
| | - Amila Manuradha Devasurendra
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109, USA
| | - Christopher Godwin
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sung Kyun Park
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109, USA; Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI 48109, USA
| | - Stuart Batterman
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109, USA.
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29
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Huang X, Zhang Y, Wang Y, Ou Y, Chen D, Pei C, Huang Z, Zhang Z, Liu T, Luo S, Huang X, Song W, Ding X, Shao M, Zou S, Wang X. Evaluating the effectiveness of multiple emission control measures on reducing volatile organic compounds in ambient air based on observational data: A case study during the 2010 Guangzhou Asian Games. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 723:138171. [PMID: 32392684 DOI: 10.1016/j.scitotenv.2020.138171] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/22/2020] [Accepted: 03/22/2020] [Indexed: 06/11/2023]
Abstract
Volatile organic compounds (VOCs) play a crucial role in modulating air pollution by ozone and fine particles, particularly in urban areas. While in recent years short-term intervention actions for better air quality during big events in China did present good opportunities to examine the effectiveness of control measures in reducing anthropogenic VOCs emission, it is highly challenging to interpret the real effect of a specific control measure based on field monitoring data when a cocktail of control measures were adopted. Here we took the air quality intervention actions during the 16th Asian Games (AG) in Guangzhou as a case study to explore the impact of short-term multiple measures on VOCs reduction. The average mass concentrations of VOCs decreased by 52-68% during the AG. These percentages could not reflect emission reduction rates as the concentration might be also heavily impacted by dispersion conditions. Diagnostic ratios, such as methyl tert-butyl ether to carbon monoxide (MTBE/CO) and i-pentane/CO, decreased by over 60% during the AG, suggesting a substantial reduction in gasoline related emissions. A method linking emission reduction rates of two sources with their contribution percentages before and during the AG by using a receptor model was further formulated. With the available reduction rate of 34% for vehicular exhaust obtained during the traffic restriction drill in our previous study, VOCs emissions from gasoline evaporation and solvent use reduced by 45.7% and 13.6% during the AG, respectively. Total VOCs emissions decreased by 25.3% on average during the AG, and the emission control of vehicular exhaust, oil evaporation, and solvent use accounted for 17.0%, 6.3% and 2.0% of total VOCs emission reduction, respectively. This study presented an observed-based method with diagnostic/quantitative approaches to single out the effectiveness of each control measures in reducing VOCs emissions.
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Affiliation(s)
- Xinyu Huang
- School of Marine Sciences, Sun Yat-sen University, Guangzhou 510006, China; State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Yanli Zhang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
| | - Yujun Wang
- Guangzhou Environmental Monitoring Center, Guangzhou 510030, China
| | - Yubo Ou
- Guangdong Environmental Monitoring Center, Guangzhou 510308, China
| | - Duohong Chen
- Guangdong Environmental Monitoring Center, Guangzhou 510308, China
| | - Chenglei Pei
- Guangzhou Environmental Monitoring Center, Guangzhou 510030, China
| | - Zuzhao Huang
- Guangzhou Environmental Technology Center, Guangzhou 510180, China
| | - Zhou Zhang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Tengyu Liu
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Shilu Luo
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoqing Huang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Song
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Xiang Ding
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Min Shao
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China
| | - Shichun Zou
- School of Marine Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Xinming Wang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China
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30
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Lu Q, Murphy BN, Qin M, Adams PJ, Zhao Y, Pye HOT, Efstathiou C, Allen C, Robinson AL. Simulation of organic aerosol formation during the CalNex study: updated mobile emissions and secondary organic aerosol parameterization for intermediate-volatility organic compounds. ATMOSPHERIC CHEMISTRY AND PHYSICS 2020; 20:4313-4332. [PMID: 32461753 PMCID: PMC7252505 DOI: 10.5194/acp-20-4313-2020] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We describe simulations using an updated version of the Community Multiscale Air Quality model version 5.3 (CMAQ v5.3) to investigate the contribution of intermediate-volatility organic compounds (IVOCs) to secondary organic aerosol (SOA) formation in southern California during the CalNex study. We first derive a model-ready parameterization for SOA formation from IVOC emissions from mobile sources. To account for SOA formation from both diesel and gasoline sources, the parameterization has six lumped precursor species that resolve both volatility and molecular structure (aromatic versus aliphatic). We also implement new mobile-source emission profiles that quantify all IVOCs based on direct measurements. The profiles have been released in SPECIATE 5.0. By incorporating both comprehensive mobile-source emission profiles for semivolatile organic compounds (SVOCs) and IVOCs and experimentally constrained SOA yields, this CMAQ configuration best represents the contribution of mobile sources to urban and regional ambient organic aerosol (OA). In the Los Angeles region, gasoline sources emit 4 times more non-methane organic gases (NMOGs) than diesel sources, but diesel emits roughly 3 times more IVOCs on an absolute basis. The revised model predicts all mobile sources (including on- and off-road gasoline, aircraft, and on- and off-road diesel) contribute ~ 1 μgm-3 to the daily peak SOA concentration in Pasadena. This represents a ~ 70% increase in predicted daily peak SOA formation compared to the base version of CMAQ. Therefore, IVOCs in mobile-source emissions contribute almost as much SOA as traditional precursors such as single-ring aromatics. However, accounting for these emissions in CMAQ does not reproduce measurements of either ambient SOA or IVOCs. To investigate the potential contribution of other IVOC sources, we performed two exploratory simulations with varying amounts of IVOC emissions from nonmobile sources. To close the mass balance of primary hydrocarbon IVOCs, IVOCs would need to account for 12% of NMOG emissions from nonmobile sources (or equivalently 30.7 t d-1 in the Los Angeles-Pasadena region), a value that is well within the reported range of IVOC content from volatile chemical products. To close the SOA mass balance and also explain the mildly oxygenated IVOCs in Pasadena, an additional 14.8% of nonmobile-source NMOG emissions would need to be IVOCs (assuming SOA yields from the mobile IVOCs apply to nonmobile IVOCs). However, an IVOC-to-NMOG ratio of 26.8% (or equivalently 68.5 t d-1 in the Los Angeles-Pasadena region) for nonmobile sources is likely unrealistically high. Our results highlight the important contribution of IVOCs to SOA production in the Los Angeles region but underscore that other uncertainties must be addressed (multigenerational aging, aqueous chemistry and vapor wall losses) to close the SOA mass balance. This research also highlights the effectiveness of regulations to reduce mobile-source emissions, which have in turn increased the relative importance of other sources, such as volatile chemical products.
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Affiliation(s)
- Quanyang Lu
- Center of Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA, USA
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
- Oak Ridge Institute for Science and Education (ORISE) Research Participation Program at the Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Benjamin N Murphy
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Momei Qin
- Oak Ridge Institute for Science and Education (ORISE) Research Participation Program at the Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Peter J Adams
- Center of Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Yunliang Zhao
- Center of Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA, USA
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Havala O T Pye
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Christos Efstathiou
- General Dynamics Information Technology Research Triangle Park, North Carolina, USA
| | - Chris Allen
- General Dynamics Information Technology Research Triangle Park, North Carolina, USA
| | - Allen L Robinson
- Center of Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA, USA
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
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Wang X, Liu G, Hu R, Zhang H, Zhang M, Zhang F. Distribution, Sources, and Health Risk Assessment of Volatile Organic Compounds in Hefei City. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2020; 78:392-400. [PMID: 31932858 DOI: 10.1007/s00244-019-00704-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 12/27/2019] [Indexed: 06/10/2023]
Abstract
Volatile organic compounds (VOCs) are involved in the formation of ozone formation, which plays a significant role in regional air contamination and poses a great threat to human health. The VOCs were collected from the urban area of Hefei city via an off-line sampling method (SUMMA canister) and determined by gas chromatography-mass spectrometer. The average concentrations of VOCs were 17.65 ± 28.36 ppbv, which were mainly contributed by aromatics (10.02 ± 13.37 ppbv), haloalkane (5.37 ± 8.90 ppbv), ally halide (1.25 ± 3.36 ppbv), and aryl halid (1.02 ± 2.73 ppbv). According to the principal component analysis, three major sources were identified, including solvent use, vehicle exhaust, and industrial release, accounting for 70.6% of the total variance of the data. Health risk assessment was utilized to evaluate the potential adverse health effects of the individual VOC. The total hazard ratio in the selected area was higher than 1, where could pose health threat to exposed population. The cancer risk for benzene, carbon tetrachloride, trichloromethane, and 1, 2-dichloroethane were 4.8 × 10-5, 4.5 × 10-5, 3.3 × 10-5, and 2.5 × 10-5, respectively, indicating definite health risks.
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Affiliation(s)
- Xin Wang
- CAS Key Laboratory of Crust-Mantle Materials and Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, Anhui, China
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences, Xi'an, 710075, Shaanxi, China
- Anhui Environmental Monitoring Center Station, Hefei, 230022, Anhui, China
| | - Guijian Liu
- CAS Key Laboratory of Crust-Mantle Materials and Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, Anhui, China.
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences, Xi'an, 710075, Shaanxi, China.
| | - Ruoyu Hu
- CAS Key Laboratory of Crust-Mantle Materials and Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, Anhui, China
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences, Xi'an, 710075, Shaanxi, China
| | - Hong Zhang
- CAS Key Laboratory of Crust-Mantle Materials and Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, Anhui, China
| | - Min Zhang
- Anhui Environmental Monitoring Center Station, Hefei, 230022, Anhui, China
| | - Fuhai Zhang
- Anhui Environmental Monitoring Center Station, Hefei, 230022, Anhui, China
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32
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Day M, Pouliot G, Hunt S, Baker KR, Beardsley M, Frost G, Mobley D, Simon H, Henderson BB, Yelverton T, Rao V. Reflecting on progress since the 2005 NARSTO emissions inventory report. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2019; 69:1023-1048. [PMID: 31184543 PMCID: PMC6784547 DOI: 10.1080/10962247.2019.1629363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 05/16/2019] [Indexed: 06/09/2023]
Abstract
Emission inventories are the foundation for cost-effective air quality management activities. In 2005, a report by the public/private partnership North American Research Strategy for Tropospheric Ozone (NARSTO) evaluated the strengths and weaknesses of North American emissions inventories and made recommendations for improving their effectiveness. This paper reviews the recommendation areas and briefly discusses what has been addressed, what remains unchanged, and new questions that have arisen. The findings reveal that all emissions inventory improvement areas identified by the 2005 NARSTO publication have been explored and implemented to some degree. The U.S. National Emissions Inventory has become more detailed and has incorporated new research into previously under-characterized sources such as fine particles and biomass burning. Additionally, it is now easier to access the emissions inventory and the documentation of the inventory via the internet. However, many emissions-related research needs exist, on topics such as emission estimation methods, speciation, scalable emission factor development, incorporation of new emission measurement techniques, estimation of uncertainty, top-down verification, and analysis of uncharacterized sources. A common theme throughout this retrospective summary is the need for increased coordination among stakeholders. Researchers and inventory developers must work together to ensure that planned emissions research and new findings can be used to update the emissions inventory. To continue to address emissions inventory challenges, industry, the scientific community, and government agencies need to continue to leverage resources and collaborate as often as possible. As evidenced by the progress noted, continued investment in and coordination of emissions inventory activities will provide dividends to air quality management programs across the country, continent, and world. Implications: In 2005, a report by the public/private partnership North American Research Strategy for Tropospheric Ozone (NARSTO) evaluated the strengths and weaknesses of North American air pollution emissions inventories. This paper reviews the eight recommendation areas and briefly discusses what has been addressed, what remains unchanged, and new questions that have arisen. Although progress has been made, many opportunities exist for the scientific agencies, industry, and government agencies to leverage resources and collaborate to continue improving emissions inventories.
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Affiliation(s)
- Melissa Day
- 2015-2017 AAAS Science & Technology Policy Fellow, Environmental Protection Agency , Washington , DC , USA
| | - George Pouliot
- Office of Research and Development, Environmental Protection Agency , Research Triangle Park , NC , USA
| | - Sherri Hunt
- Office of Research and Development, Environmental Protection Agency , Research Triangle Park , NC , USA
| | - Kirk R Baker
- Office of Air and Radiation, Environmental Protection Agency , Research Triangle Park , NC , USA
| | - Megan Beardsley
- Office of Transportation and Air Quality, Environmental Protection Agency , Ann Arbor , MI , USA
| | - Gregory Frost
- Earth System Research Laboratory, National Oceanic and Atmospheric Administration , Boulder , CO , USA
| | - David Mobley
- Office of Research and Development, Environmental Protection Agency , Research Triangle Park , NC , USA
- Office of Air and Radiation, Environmental Protection Agency , Research Triangle Park , NC , USA
| | - Heather Simon
- Office of Air and Radiation, Environmental Protection Agency , Research Triangle Park , NC , USA
| | - Barron B Henderson
- Office of Air and Radiation, Environmental Protection Agency , Research Triangle Park , NC , USA
| | - Tiffany Yelverton
- Office of Research and Development, Environmental Protection Agency , Research Triangle Park , NC , USA
| | - Venkatesh Rao
- Office of Air and Radiation, Environmental Protection Agency , Research Triangle Park , NC , USA
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Chen X, Millet DB, Singh HB, Wisthaler A, Apel EC, Atlas EL, Blake DR, Bourgeois I, Brown SS, Crounse JD, de Gouw JA, Flocke FM, Fried A, Heikes BG, Hornbrook RS, Mikoviny T, Min KE, Müller M, Neuman JA, O'Sullivan DW, Peischl J, Pfister GG, Richter D, Roberts JM, Ryerson TB, Shertz SR, Thompson CR, Treadaway V, Veres PR, Walega J, Warneke C, Washenfelder RA, Weibring P, Yuan B. On the sources and sinks of atmospheric VOCs: an integrated analysis of recent aircraft campaigns over North America. ATMOSPHERIC CHEMISTRY AND PHYSICS 2019; 19:9097-9123. [PMID: 33688334 PMCID: PMC7939023 DOI: 10.5194/acp-19-9097-2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We apply a high-resolution chemical transport model (GEOS-Chem CTM) with updated treatment of volatile organic compounds (VOCs) and a comprehensive suite of airborne datasets over North America to (i) characterize the VOC budget and (ii) test the ability of current models to capture the distribution and reactivity of atmospheric VOCs over this region. Biogenic emissions dominate the North American VOC budget in the model, accounting for 70 % and 95 % of annually emitted VOC carbon and reactivity, respectively. Based on current inventories anthropogenic emissions have declined to the point where biogenic emissions are the dominant summertime source of VOC reactivity even in most major North American cities. Methane oxidation is a 2x larger source of nonmethane VOCs (via production of formaldehyde and methyl hydroperoxide) over North America in the model than are anthropogenic emissions. However, anthropogenic VOCs account for over half of the ambient VOC loading over the majority of the region owing to their longer aggregate lifetime. Fires can be a significant VOC source episodically but are small on average. In the planetary boundary layer (PBL), the model exhibits skill in capturing observed variability in total VOC abundance (R 2 = 0:36) and reactivity (R 2 = 0:54). The same is not true in the free troposphere (FT), where skill is low and there is a persistent low model bias (~ 60 %), with most (27 of 34) model VOCs underestimated by more than a factor of 2. A comparison of PBL: FT concentration ratios over the southeastern US points to a misrepresentation of PBL ventilation as a contributor to these model FT biases. We also find that a relatively small number of VOCs (acetone, methanol, ethane, acetaldehyde, formaldehyde, isoprene C oxidation products, methyl hydroperoxide) drive a large fraction of total ambient VOC reactivity and associated model biases; research to improve understanding of their budgets is thus warranted. A source tracer analysis suggests a current overestimate of biogenic sources for hydroxyacetone, methyl ethyl ketone and glyoxal, an underestimate of biogenic formic acid sources, and an underestimate of peroxyacetic acid production across biogenic and anthropogenic precursors. Future work to improve model representations of vertical transport and to address the VOC biases discussed are needed to advance predictions of ozone and SOA formation.
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Affiliation(s)
- Xin Chen
- Department of Soil, Water, and Climate, University of Minnesota, Minneapolis-Saint Paul, MN, USA
| | - Dylan B. Millet
- Department of Soil, Water, and Climate, University of Minnesota, Minneapolis-Saint Paul, MN, USA
| | | | - Armin Wisthaler
- Institute for Ion Physics and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria
- Department of Chemistry, University of Oslo, Oslo, Norway
| | - Eric C. Apel
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Elliot L. Atlas
- Department of Atmospheric Sciences, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
| | - Donald R. Blake
- Department of Chemistry, University of California, Irvine, Irvine, CA, USA
| | - Ilann Bourgeois
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - Steven S. Brown
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - John D. Crounse
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Joost A. de Gouw
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - Frank M. Flocke
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Alan Fried
- Institute of Arctic & Alpine Research, University of Colorado, Boulder, CO, USA
| | - Brian G. Heikes
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA
| | - Rebecca S. Hornbrook
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Tomas Mikoviny
- Department of Chemistry, University of Oslo, Oslo, Norway
| | - Kyung-Eun Min
- School of Earth Science and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju, South Korea
| | - Markus Müller
- Institute for Ion Physics and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria
| | - J. Andrew Neuman
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | | | - Jeff Peischl
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - Gabriele G. Pfister
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Dirk Richter
- Institute of Arctic & Alpine Research, University of Colorado, Boulder, CO, USA
| | - James M. Roberts
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Thomas B. Ryerson
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Stephen R. Shertz
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Chelsea R. Thompson
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - Victoria Treadaway
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA
| | - Patrick R. Veres
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - James Walega
- Institute of Arctic & Alpine Research, University of Colorado, Boulder, CO, USA
| | - Carsten Warneke
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | | | - Petter Weibring
- Institute of Arctic & Alpine Research, University of Colorado, Boulder, CO, USA
| | - Bin Yuan
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China
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Drozd GT, Zhao Y, Saliba G, Frodin B, Maddox C, Oliver Chang MC, Maldonado H, Sardar S, Weber RJ, Robinson AL, Goldstein AH. Detailed Speciation of Intermediate Volatility and Semivolatile Organic Compound Emissions from Gasoline Vehicles: Effects of Cold-Starts and Implications for Secondary Organic Aerosol Formation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:1706-1714. [PMID: 30583696 DOI: 10.1021/acs.est.8b05600] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Over the past two decades vehicle emission standards in the United States have been dramatically tightened with the goal of reducing urban air pollution. Secondary organic aerosol (SOA) is the dominant contributor to urban organic aerosol. Experiments were conducted at the California Air Resources Board Haagen-Smit Laboratory to characterize exhaust organics from 20 gasoline vehicles recruited from the California in-use fleet. The vehicles spanned a wide range of emission certification standards. We comprehensively characterized intermediate volatility and semivolatile organic compound emissions using thermal desorption two-dimensional gas-chromatography-mass-spectrometry with electron impact (GC × GC-EI-MS) and vacuum-ultraviolet (GC × GC-VUV-MS) ionization. Single-ring aromatic compounds with unsaturated C4 and C5 substituents contribute a large fraction of the intermediate volatility organic compound (IVOC) emissions in gasoline vehicle exhaust. The analyses of quartz filters used in GC × GC-VUV-MS show that primary organic aerosol emissions were dominated by motor oil. We combined our new emissions data with published SOA yield parametrizations to estimate SOA formation potential. After 24 h of oxidation, IVOC emissions contributed 45% of SOA formation; BTEX compounds (benzene, toluene, xylenes, and ethylbenzene), 40%; other VOC aromatics, 15%. The composition of IVOC emissions was consistent across the test fleet, suggesting that future reductions in vehicular emissions will continue to reduce SOA formation and ambient particulate mass levels.
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Affiliation(s)
- Greg T Drozd
- Department of Chemistry , Colby College , Waterville , Maine 04901 , United States
| | - Yunliang Zhao
- Center for Atmospheric Particle Studies , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Georges Saliba
- Center for Atmospheric Particle Studies , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Bruce Frodin
- California Air Resources Board , Sacramento , California 95814 , United States
| | - Christine Maddox
- California Air Resources Board , Sacramento , California 95814 , United States
| | - M-C Oliver Chang
- California Air Resources Board , Sacramento , California 95814 , United States
| | - Hector Maldonado
- California Air Resources Board , Sacramento , California 95814 , United States
| | - Satya Sardar
- California Air Resources Board , Sacramento , California 95814 , United States
| | - Robert Jay Weber
- Department of Environmental Science, Policy, and Management , University of California , Berkeley , California 94720 , United States
| | - Allen L Robinson
- Center for Atmospheric Particle Studies , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Allen H Goldstein
- Department of Environmental Science, Policy, and Management , University of California , Berkeley , California 94720 , United States
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35
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McDonald BC, McKeen SA, Cui YY, Ahmadov R, Kim SW, Frost GJ, Pollack IB, Peischl J, Ryerson TB, Holloway JS, Graus M, Warneke C, Gilman JB, de Gouw JA, Kaiser J, Keutsch FN, Hanisco TF, Wolfe GM, Trainer M. Modeling Ozone in the Eastern U.S. using a Fuel-Based Mobile Source Emissions Inventory. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:7360-7370. [PMID: 29870662 DOI: 10.1021/acs.est.8b00778] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Recent studies suggest overestimates in current U.S. emission inventories of nitrogen oxides (NO x = NO + NO2). Here, we expand a previously developed fuel-based inventory of motor-vehicle emissions (FIVE) to the continental U.S. for the year 2013, and evaluate our estimates of mobile source emissions with the U.S. Environmental Protection Agency's National Emissions Inventory (NEI) interpolated to 2013. We find that mobile source emissions of NO x and carbon monoxide (CO) in the NEI are higher than FIVE by 28% and 90%, respectively. Using a chemical transport model, we model mobile source emissions from FIVE, and find consistent levels of urban NO x and CO as measured during the Southeast Nexus (SENEX) Study in 2013. Lastly, we assess the sensitivity of ozone (O3) over the Eastern U.S. to uncertainties in mobile source NO x emissions and biogenic volatile organic compound (VOC) emissions. The ground-level O3 is sensitive to reductions in mobile source NO x emissions, most notably in the Southeastern U.S. and during O3 exceedance events, under the revised standard proposed in 2015 (>70 ppb, 8 h maximum). This suggests that decreasing mobile source NO x emissions could help in meeting more stringent O3 standards in the future.
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Affiliation(s)
- Brian C McDonald
- Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder , Colorado 80309 , United States
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
| | - Stuart A McKeen
- Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder , Colorado 80309 , United States
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
| | - Yu Yan Cui
- Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder , Colorado 80309 , United States
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
| | - Ravan Ahmadov
- Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder , Colorado 80309 , United States
- Global Systems Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
| | - Si-Wan Kim
- Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder , Colorado 80309 , United States
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
| | - Gregory J Frost
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
| | - Ilana B Pollack
- Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder , Colorado 80309 , United States
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
| | - Jeff Peischl
- Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder , Colorado 80309 , United States
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
| | - Thomas B Ryerson
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
| | - John S Holloway
- Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder , Colorado 80309 , United States
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
| | - Martin Graus
- Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder , Colorado 80309 , United States
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
| | - Carsten Warneke
- Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder , Colorado 80309 , United States
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
| | - Jessica B Gilman
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
| | - Joost A de Gouw
- Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder , Colorado 80309 , United States
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
| | - Jennifer Kaiser
- Department of Chemistry , University of Wisconsin , Madison , Wisconsin 53706 , United States
| | - Frank N Keutsch
- Department of Chemistry , University of Wisconsin , Madison , Wisconsin 53706 , United States
| | - Thomas F Hanisco
- Atmospheric Chemistry and Dynamics Laboratory , NASA Goddard Space Flight Center , Greenbelt , Maryland 20771 , United States
| | - Glenn M Wolfe
- Atmospheric Chemistry and Dynamics Laboratory , NASA Goddard Space Flight Center , Greenbelt , Maryland 20771 , United States
- Joint Center for Earth Systems Technology , University of Maryland Baltimore County , Baltimore , Maryland 21228 , United States
| | - Michael Trainer
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
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36
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Frey HC. Trends in onroad transportation energy and emissions. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2018; 68:514-563. [PMID: 29589998 DOI: 10.1080/10962247.2018.1454357] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 03/15/2018] [Indexed: 06/08/2023]
Abstract
UNLABELLED Globally, 1.3 billion on-road vehicles consume 79 quadrillion BTU of energy, mostly gasoline and diesel fuels, emit 5.7 gigatonnes of CO2, and emit other pollutants to which approximately 200,000 annual premature deaths are attributed. Improved vehicle energy efficiency and emission controls have helped offset growth in vehicle activity. New technologies are diffusing into the vehicle fleet in response to fuel efficiency and emission standards. Empirical assessment of vehicle emissions is challenging because of myriad fuels and technologies, intervehicle variability, multiple emission processes, variability in operating conditions, and varying capabilities of measurement methods. Fuel economy and emissions regulations have been effective in reducing total emissions of key pollutants. Real-world fuel use and emissions are consistent with official values in the United States but not in Europe or countries that adopt European standards. Portable emission measurements systems, which uncovered a recent emissions cheating scandal, have a key role in regulatory programs to ensure conformity between "real driving emissions" and emission standards. The global vehicle fleet will experience tremendous growth, especially in Asia. Although existing data and modeling tools are useful, they are often based on convenience samples, small sample sizes, large variability, and unquantified uncertainty. Vehicles emit precursors to several important secondary pollutants, including ozone and secondary organic aerosols, which requires a multipollutant emissions and air quality management strategy. Gasoline and diesel are likely to persist as key energy sources to mid-century. Adoption of electric vehicles is not a panacea with regard to greenhouse gas emissions unless coupled with policies to change the power generation mix. Depending on how they are actually implemented and used, autonomous vehicles could lead to very large reductions or increases in energy consumption. Numerous other trends are addressed with regard to technology, emissions controls, vehicle operations, emission measurements, impacts on exposure, and impacts on public health. IMPLICATIONS Without specific policies to the contrary, fossil fuels are likely to continue to be the major source of on-road vehicle energy consumption. Fuel economy and emission standards are generally effective in achieving reductions per unit of vehicle activity. However, the number of vehicles and miles traveled will increase. Total energy use and emissions depend on factors such as fuels, technologies, land use, demographics, economics, road design, vehicle operation, societal values, and others that affect demand for transportation, mode choice, energy use, and emissions. Thus, there are many opportunities to influence future trends in vehicle energy use and emissions.
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Affiliation(s)
- H Christopher Frey
- a Department of Civil, Construction, and Environmental Engineering , North Carolina State University, Raleigh, North Carolina, USA
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Abstract
Emissions of nitrogen oxides (NOx) have a large impact on air quality and climate change as precursors in the formation of ozone and secondary aerosols. We find that NOx emissions have not been decreasing as expected in recent years (2011–2015) when comparing top-down estimates from satellites and surface NO2 measurements to the trends predicted from the US Environmental Protection Agency’s emission inventory data. The discrepancy can be explained by the growing relative contribution of industrial, area, and off-road mobile sources of emissions, decreasing relative contribution of on-road gasoline vehicles, and slower than expected decreases in on-road diesel NOx emissions, with implications for air-quality management. Ground and satellite observations show that air pollution regulations in the United States (US) have resulted in substantial reductions in emissions and corresponding improvements in air quality over the last several decades. However, large uncertainties remain in evaluating how recent regulations affect different emission sectors and pollutant trends. Here we show a significant slowdown in decreasing US emissions of nitrogen oxides (NOx) and carbon monoxide (CO) for 2011–2015 using satellite and surface measurements. This observed slowdown in emission reductions is significantly different from the trend expected using US Environmental Protection Agency (EPA) bottom-up inventories and impedes compliance with local and federal agency air-quality goals. We find that the difference between observations and EPA’s NOx emission estimates could be explained by: (i) growing relative contributions of industrial, area, and off-road sources, (ii) decreasing relative contributions of on-road gasoline, and (iii) slower than expected decreases in on-road diesel emissions.
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McDonald BC, de Gouw JA, Gilman JB, Jathar SH, Akherati A, Cappa CD, Jimenez JL, Lee-Taylor J, Hayes PL, McKeen SA, Cui YY, Kim SW, Gentner DR, Isaacman-VanWertz G, Goldstein AH, Harley RA, Frost GJ, Roberts JM, Ryerson TB, Trainer M. Volatile chemical products emerging as largest petrochemical source of urban organic emissions. Science 2018; 359:760-764. [PMID: 29449485 DOI: 10.1126/science.aaq0524] [Citation(s) in RCA: 351] [Impact Index Per Article: 58.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 12/22/2017] [Indexed: 11/02/2022]
Abstract
A gap in emission inventories of urban volatile organic compound (VOC) sources, which contribute to regional ozone and aerosol burdens, has increased as transportation emissions in the United States and Europe have declined rapidly. A detailed mass balance demonstrates that the use of volatile chemical products (VCPs)-including pesticides, coatings, printing inks, adhesives, cleaning agents, and personal care products-now constitutes half of fossil fuel VOC emissions in industrialized cities. The high fraction of VCP emissions is consistent with observed urban outdoor and indoor air measurements. We show that human exposure to carbonaceous aerosols of fossil origin is transitioning away from transportation-related sources and toward VCPs. Existing U.S. regulations on VCPs emphasize mitigating ozone and air toxics, but they currently exempt many chemicals that lead to secondary organic aerosols.
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Affiliation(s)
- Brian C McDonald
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA. .,Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Joost A de Gouw
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.,Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Jessica B Gilman
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Shantanu H Jathar
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO, USA
| | - Ali Akherati
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO, USA
| | - Christopher D Cappa
- Department of Civil and Environmental Engineering, University of California, Davis, CA, USA
| | - Jose L Jimenez
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.,Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - Julia Lee-Taylor
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.,National Center for Atmospheric Research, Boulder, CO, USA
| | - Patrick L Hayes
- Department of Chemistry, Université de Montréal, Montréal, Quebec, Canada
| | - Stuart A McKeen
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.,Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Yu Yan Cui
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.,Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Si-Wan Kim
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.,Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Drew R Gentner
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, USA.,School of Forestry and Environmental Studies, Yale University, New Haven, CT, USA
| | - Gabriel Isaacman-VanWertz
- Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Allen H Goldstein
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA.,Department of Civil and Environmental Engineering, University of California, Berkeley, CA, USA
| | - Robert A Harley
- Department of Civil and Environmental Engineering, University of California, Berkeley, CA, USA
| | - Gregory J Frost
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - James M Roberts
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Thomas B Ryerson
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Michael Trainer
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
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39
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Mao J, Carlton A, Cohen RC, Brune WH, Brown SS, Wolfe GM, Jimenez JL, Pye HOT, Ng NL, Xu L, McNeill VF, Tsigaridis K, McDonald BC, Warneke C, Guenther A, Alvarado MJ, de Gouw J, Mickley LJ, Leibensperger EM, Mathur R, Nolte CG, Portmann RW, Unger N, Tosca M, Horowitz LW. Southeast Atmosphere Studies: learning from model-observation syntheses. ATMOSPHERIC CHEMISTRY AND PHYSICS 2018; 18:2615-2651. [PMID: 29963079 PMCID: PMC6020695 DOI: 10.5194/acp-18-2615-2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Concentrations of atmospheric trace species in the United States have changed dramatically over the past several decades in response to pollution control strategies, shifts in domestic energy policy and economics, and economic development (and resulting emission changes) elsewhere in the world. Reliable projections of the future atmosphere require models to not only accurately describe current atmospheric concentrations, but to do so by representing chemical, physical and biological processes with conceptual and quantitative fidelity. Only through incorporation of the processes controlling emissions and chemical mechanisms that represent the key transformations among reactive molecules can models reliably project the impacts of future policy, energy and climate scenarios. Efforts to properly identify and implement the fundamental and controlling mechanisms in atmospheric models benefit from intensive observation periods, during which collocated measurements of diverse, speciated chemicals in both the gas and condensed phases are obtained. The Southeast Atmosphere Studies (SAS, including SENEX, SOAS, NOMADSS and SEAC4RS) conducted during the summer of 2013 provided an unprecedented opportunity for the atmospheric modeling community to come together to evaluate, diagnose and improve the representation of fundamental climate and air quality processes in models of varying temporal and spatial scales. This paper is aimed at discussing progress in evaluating, diagnosing and improving air quality and climate modeling using comparisons to SAS observations as a guide to thinking about improvements to mechanisms and parameterizations in models. The effort focused primarily on model representation of fundamental atmospheric processes that are essential to the formation of ozone, secondary organic aerosol (SOA) and other trace species in the troposphere, with the ultimate goal of understanding the radiative impacts of these species in the southeast and elsewhere. Here we address questions surrounding four key themes: gas-phase chemistry, aerosol chemistry, regional climate and chemistry interactions, and natural and anthropogenic emissions. We expect this review to serve as a guidance for future modeling efforts.
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Affiliation(s)
- Jingqiu Mao
- Geophysical Institute and Department of Chemistry, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Annmarie Carlton
- Department of Environmental Sciences, Rutgers University, New Brunswick, NJ, USA
| | - Ronald C. Cohen
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA, USA
| | - William H. Brune
- Department of Meteorology, Pennsylvania State University, University Park, PA, USA
| | - Steven S. Brown
- Department of Chemistry and CIRES, University of Colorado Boulder, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Boulder, CO, USA
| | - Glenn M. Wolfe
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Joint Center for Earth Systems Technology, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Jose L. Jimenez
- Department of Chemistry and CIRES, University of Colorado Boulder, Boulder, CO, USA
| | - Havala O. T. Pye
- National Exposure Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Nga Lee Ng
- School of Chemical and Biomolecular Engineering and School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Lu Xu
- School of Chemical and Biomolecular Engineering and School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - V. Faye McNeill
- Department of Chemical Engineering, Columbia University, New York, NY USA
| | - Kostas Tsigaridis
- Center for Climate Systems Research, Columbia University, New York, NY, USA
- NASA Goddard Institute for Space Studies, New York, NY, USA
| | - Brian C. McDonald
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Boulder, CO, USA
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Carsten Warneke
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Boulder, CO, USA
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Alex Guenther
- Department of Earth System Science, University of California, Irvine, CA, USA
| | | | - Joost de Gouw
- Department of Chemistry and CIRES, University of Colorado Boulder, Boulder, CO, USA
| | - Loretta J. Mickley
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | | | - Rohit Mathur
- National Exposure Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Christopher G. Nolte
- National Exposure Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Robert W. Portmann
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Boulder, CO, USA
| | - Nadine Unger
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Mika Tosca
- School of the Art Institute of Chicago (SAIC), Chicago, IL 60603, USA
| | - Larry W. Horowitz
- Geophysical Fluid Dynamics Laboratory–National Oceanic and Atmospheric Administration, Princeton, NJ, USA
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40
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Household chemicals rival vehicles as smog source. Nature 2018. [DOI: 10.1038/d41586-018-02132-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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41
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Borbon A, Boynard A, Salameh T, Baudic A, Gros V, Gauduin J, Perrussel O, Pallares C. Is Traffic Still an Important Emitter of Monoaromatic Organic Compounds in European Urban Areas? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:513-521. [PMID: 29164867 DOI: 10.1021/acs.est.7b01408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Trends of long-term observations and emission inventories suggest that traffic emissions will no longer dominate the concentrations of monoaromatic compounds (i.e., TEX - toluene, xylenes, and ethylbenzene) in European urban areas. But the split limit between traffic and other emission sector contributions such as solvent use remains tenuous. Here long-term observations of an extensive set of hydrocarbons, including TEX, at traffic and urban background sites in London, Paris and Strasbourg were combined to estimate the relative importance of traffic emissions on TEX in every city. When analyzing the urban enhancement emission ratios of TEX-to-benzene on a seasonal basis, two potential source signatures other than traffic could be differentiated in all cities (1) summertime evaporation from fuel and/or solvent and (2) wintertime domestic heating. However, traffic emissions still unambiguously dominate the concentration levels of TEX in every city despite the reduction of their emissions at exhaust pipe over the last two decades. Traffic explains between 60% and 96% (at ±20%) of TEX levels while it is less clear for xylenes at some locations. Our results provide a basis to evaluate regional emission inventories. The method is applicable at any urban area where speciated hydrocarbon monitoring is available.
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Affiliation(s)
- Agnès Borbon
- Université Clermont Auvergne , CNRS, LaMP, F-63000 Clermont-Ferrand, France
| | - Anne Boynard
- UVSQ, CNRS, LATMOS/IPSL, UPMC Univ. Paris 06 Sorbonne Universités , Paris, France
| | - Thérèse Salameh
- Laboratoire Inter-Universitaire des Systèmes Atmosphériques (LISA), UMR CNRS 7583, Université Paris Est Créteil et Université Paris Diderot, Institut Pierre Simon Laplace , Créteil, France
| | - Alexia Baudic
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE), UMR CNRS 8212, Commissariat à l'Energie Atomique et aux énergies alternatives, Université Versailles Saint-Quentin, Institut Pierre-Simon Laplace , Gif sur Yvette, France
- AIRPARIF, Association Agréée de Surveillance de la Qualité de l'Air en Île-de-France, 75004 Paris, France
| | - Valérie Gros
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE), UMR CNRS 8212, Commissariat à l'Energie Atomique et aux énergies alternatives, Université Versailles Saint-Quentin, Institut Pierre-Simon Laplace , Gif sur Yvette, France
| | - Julie Gauduin
- AIRPARIF, Association Agréée de Surveillance de la Qualité de l'Air en Île-de-France, 75004 Paris, France
| | - Olivier Perrussel
- AIRPARIF, Association Agréée de Surveillance de la Qualité de l'Air en Île-de-France, 75004 Paris, France
| | - Cyril Pallares
- Agence de surveillance de la qualité de l'air (ASPA), F-67300, Schiltigheim, France
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42
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Morgott DA. The Human Exposure Potential from Propylene Releases to the Environment. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15010066. [PMID: 29300328 PMCID: PMC5800165 DOI: 10.3390/ijerph15010066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 12/22/2017] [Accepted: 12/23/2017] [Indexed: 11/16/2022]
Abstract
A detailed literature search was performed to assess the sources, magnitudes and extent of human inhalation exposure to propylene. Exposure evaluations were performed at both the community and occupational levels for those living or working in different environments. The results revealed a multitude of pyrogenic, biogenic and anthropogenic emission sources. Pyrogenic sources, including biomass burning and fossil fuel combustion, appear to be the primary contributors to atmospheric propylene. Despite a very short atmospheric lifetime, measurable levels could be detected in highly remote locations as a result of biogenic release. The indoor/outdoor ratio for propylene has been shown to range from about 2 to 3 in non-smoking homes, which indicates that residential sources may be the largest contributor to the overall exposure for those not occupationally exposed. In homes where smoking takes place, the levels may be up to thirty times higher than non-smoking residences. Atmospheric levels in most rural regions are typically below 2 ppbv, whereas the values in urban levels are much more variable ranging as high as 10 ppbv. Somewhat elevated propylene exposures may also occur in the workplace; especially for firefighters or refinery plant operators who may encounter levels up to about 10 ppmv.
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Affiliation(s)
- David A Morgott
- Pennsport Consulting, LLC, 1 Christian Street, Unit#21, Philadelphia, PA 19147, USA.
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43
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Praske E, Otkjær RV, Crounse JD, Hethcox JC, Stoltz BM, Kjaergaard HG, Wennberg PO. Atmospheric autoxidation is increasingly important in urban and suburban North America. Proc Natl Acad Sci U S A 2018; 115:64-69. [PMID: 29255042 PMCID: PMC5776813 DOI: 10.1073/pnas.1715540115] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Gas-phase autoxidation-regenerative peroxy radical formation following intramolecular hydrogen shifts-is known to be important in the combustion of organic materials. The relevance of this chemistry in the oxidation of organics in the atmosphere has received less attention due, in part, to the lack of kinetic data at relevant temperatures. Here, we combine computational and experimental approaches to investigate the rate of autoxidation for organic peroxy radicals (RO2) produced in the oxidation of a prototypical atmospheric pollutant, n-hexane. We find that the reaction rate depends critically on the molecular configuration of the RO2 radical undergoing hydrogen transfer (H-shift). RO2 H-shift rate coefficients via transition states involving six- and seven-membered rings (1,5 and 1,6 H-shifts, respectively) of α-OH hydrogens (HOC-H) formed in this system are of order 0.1 s-1 at 296 K, while the 1,4 H-shift is calculated to be orders of magnitude slower. Consistent with H-shift reactions over a substantial energetic barrier, we find that the rate coefficients of these reactions increase rapidly with temperature and exhibit a large, primary, kinetic isotope effect. The observed H-shift rate coefficients are sufficiently fast that, as a result of ongoing NO x emission reductions, autoxidation is now competing with bimolecular chemistry even in the most polluted North American cities, particularly during summer afternoons when NO levels are low and temperatures are elevated.
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Affiliation(s)
- Eric Praske
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Rasmus V Otkjær
- Department of Chemistry, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - John D Crounse
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125
| | - J Caleb Hethcox
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Brian M Stoltz
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Henrik G Kjaergaard
- Department of Chemistry, University of Copenhagen, DK-2100 Copenhagen, Denmark;
| | - Paul O Wennberg
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125;
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125
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44
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Singhal S, Leon Guerrero CM, Whang SG, McClure EM, Busch HG, Kerr B. Adaptations of an RNA virus to increasing thermal stress. PLoS One 2017; 12:e0189602. [PMID: 29267297 PMCID: PMC5739421 DOI: 10.1371/journal.pone.0189602] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 11/28/2017] [Indexed: 11/18/2022] Open
Abstract
Environments can change in incremental fashions, where a shift from one state to another occurs over multiple organismal generations. The rate of the environmental change is expected to influence how and how well populations adapt to the final environmental state. We used a model system, the lytic RNA bacteriophage Φ6, to investigate this question empirically. We evolved viruses for thermostability by exposing them to heat shocks that increased to a maximum temperature at different rates. We observed increases in the ability of many heat-shocked populations to survive high temperature heat shocks. On their first exposure to the highest temperature, populations that experienced a gradual increase in temperature had higher average survival than populations that experienced a rapid temperature increase. However, at the end of the experiment, neither the survival of populations at the highest temperature nor the number of mutations per population varied significantly according to the rate of thermal change. We also evaluated mutations from the endpoint populations for their effects on viral thermostability and growth. As expected, some mutations did increase viral thermostability. However, other mutations decreased thermostability but increased growth rate, suggesting that benefits of an increased replication rate may have sometimes outweighed the benefits of enhanced thermostability. Our study highlights the importance of considering the effects of multiple selective pressures, even in environments where a single factor changes.
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Affiliation(s)
- Sonia Singhal
- Department of Biology, University of Washington, Seattle, WA, United States of America
| | | | - Stella G Whang
- Department of Biology, University of Washington, Seattle, WA, United States of America
| | - Erin M McClure
- Department of Biology, University of Washington, Seattle, WA, United States of America
| | - Hannah G Busch
- Department of Biology, University of Washington, Seattle, WA, United States of America
| | - Benjamin Kerr
- Department of Biology, University of Washington, Seattle, WA, United States of America
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Zhu X, Zhang S, Yu X, Zhu X, Zheng C, Gao X, Luo Z, Cen K. Controllable synthesis of hierarchical MnO x/TiO 2 composite nanofibers for complete oxidation of low-concentration acetone. JOURNAL OF HAZARDOUS MATERIALS 2017; 337:105-114. [PMID: 28511042 DOI: 10.1016/j.jhazmat.2017.03.053] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/19/2017] [Accepted: 03/24/2017] [Indexed: 06/07/2023]
Abstract
A novel hierarchical MnOx/TiO2 composite nanofiber was fabricated by combining the electrospinning technique and hydrothermal growth method. The synthesized nanomaterial, which comprised primary TiO2 nanofibers and secondary MnOx nanoneedles, was further investigated for complete catalytic oxidation of volatile organic compounds for the first time, and this presented high-oxidation performance on low-concentration acetone. The morphological, structural, physicochemical characterization, and catalytic performance analyses demonstrated that the highest catalytic activity was achieved from the obtained MnOx/TiO2 nanofiber catalyst with 30wt.% manganese loading. This finding can be ascribed to the synergistic effect of the specific hierarchical nanofibrous morphology, the abundant surface-adsorbed oxygen, the superior redox property, and the sufficient specific surface.
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Affiliation(s)
- Xuecheng Zhu
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Shuo Zhang
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Xinning Yu
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Xinbo Zhu
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Chenghang Zheng
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Xiang Gao
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, Zhejiang, China.
| | - Zhongyang Luo
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Kefa Cen
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, Zhejiang, China
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46
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Huang M, Carmichael GR, Pierce RB, Jo DS, Park RJ, Flemming J, Emmons LK, Bowman KW, Henze DK, Davila Y, Sudo K, Jonson JE, Lund MT, Janssens-Maenhout G, Dentener FJ, Keating TJ, Oetjen H, Payne VH. Impact of intercontinental pollution transport on North American ozone air pollution: an HTAP phase 2 multi-model study. ATMOSPHERIC CHEMISTRY AND PHYSICS 2017; 17:5721-5750. [PMID: 29780406 PMCID: PMC5954439 DOI: 10.5194/acp-17-5721-2017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The recent update on the US National Ambient Air Quality Standards (NAAQS) of the ground-level ozone (O3/ can benefit from a better understanding of its source contributions in different US regions during recent years. In the Hemispheric Transport of Air Pollution experiment phase 1 (HTAP1), various global models were used to determine the O3 source-receptor (SR) relationships among three continents in the Northern Hemisphere in 2001. In support of the HTAP phase 2 (HTAP2) experiment that studies more recent years and involves higher-resolution global models and regional models' participation, we conduct a number of regional-scale Sulfur Transport and dEposition Model (STEM) air quality base and sensitivity simulations over North America during May-June 2010. STEM's top and lateral chemical boundary conditions were downscaled from three global chemical transport models' (i.e., GEOS-Chem, RAQMS, and ECMWF C-IFS) base and sensitivity simulations in which the East Asian (EAS) anthropogenic emissions were reduced by 20 %. The mean differences between STEM surface O3 sensitivities to the emission changes and its corresponding boundary condition model's are smaller than those among its boundary condition models, in terms of the regional/period-mean (<10 %) and the spatial distributions. An additional STEM simulation was performed in which the boundary conditions were downscaled from a RAQMS (Realtime Air Quality Modeling System) simulation without EAS anthropogenic emissions. The scalability of O3 sensitivities to the size of the emission perturbation is spatially varying, and the full (i.e., based on a 100% emission reduction) source contribution obtained from linearly scaling the North American mean O3 sensitivities to a 20% reduction in the EAS anthropogenic emissions may be underestimated by at least 10 %. The three boundary condition models' mean O3 sensitivities to the 20% EAS emission perturbations are ~8% (May-June 2010)/~11% (2010 annual) lower than those estimated by eight global models, and the multi-model ensemble estimates are higher than the HTAP1 reported 2001 conditions. GEOS-Chem sensitivities indicate that the EAS anthropogenic NO x emissions matter more than the other EAS O3 precursors to the North American O3, qualitatively consistent with previous adjoint sensitivity calculations. In addition to the analyses on large spatial-temporal scales relative to the HTAP1, we also show results on subcontinental and event scales that are more relevant to the US air quality management. The EAS pollution impacts are weaker during observed O3 exceedances than on all days in most US regions except over some high-terrain western US rural/remote areas. Satellite O3 (TES, JPL-IASI, and AIRS) and carbon monoxide (TES and AIRS) products, along with surface measurements and model calculations, show that during certain episodes stratospheric O3 intrusions and the transported EAS pollution influenced O3 in the western and the eastern US differently. Free-running (i.e., without chemical data assimilation) global models underpredicted the transported background O3 during these episodes, posing difficulties for STEM to accurately simulate the surface O3 and its source contribution. Although we effectively improved the modeled O3 by incorporating satellite O3 (OMI and MLS) and evaluated the quality of the HTAP2 emission inventory with the Royal Netherlands Meteorological Institute-Ozone Monitoring Instrument (KNMI-OMI) nitrogen dioxide, using observations to evaluate and improve O3 source attribution still remains to be further explored.
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Affiliation(s)
- Min Huang
- George Mason University, Fairfax, VA, USA
- University of Maryland, College Park, MD, USA
| | | | - R. Bradley Pierce
- NOAA National Environmental Satellite, Data, and Information Service, Madison, WI, USA
| | | | | | | | | | - Kevin W. Bowman
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | - Yanko Davila
- University of Colorado Boulder, Boulder, CO, USA
| | - Kengo Sudo
- Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan
| | | | | | | | | | | | - Hilke Oetjen
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Vivienne H. Payne
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
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47
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Gentner DR, Jathar SH, Gordon TD, Bahreini R, Day DA, El Haddad I, Hayes PL, Pieber SM, Platt SM, de Gouw J, Goldstein AH, Harley RA, Jimenez JL, Prévôt ASH, Robinson AL. Review of Urban Secondary Organic Aerosol Formation from Gasoline and Diesel Motor Vehicle Emissions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:1074-1093. [PMID: 28000440 DOI: 10.1021/acs.est.6b04509] [Citation(s) in RCA: 170] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Secondary organic aerosol (SOA) is formed from the atmospheric oxidation of gas-phase organic compounds leading to the formation of particle mass. Gasoline- and diesel-powered motor vehicles, both on/off-road, are important sources of SOA precursors. They emit complex mixtures of gas-phase organic compounds that vary in volatility and molecular structure-factors that influence their contributions to urban SOA. However, the relative importance of each vehicle type with respect to SOA formation remains unclear due to conflicting evidence from recent laboratory, field, and modeling studies. Both are likely important, with evolving contributions that vary with location and over short time scales. This review summarizes evidence, research needs, and discrepancies between top-down and bottom-up approaches used to estimate SOA from motor vehicles, focusing on inconsistencies between molecular-level understanding and regional observations. The effect of emission controls (e.g., exhaust aftertreatment technologies, fuel formulation) on SOA precursor emissions needs comprehensive evaluation, especially with international perspective given heterogeneity in regulations and technology penetration. Novel studies are needed to identify and quantify "missing" emissions that appear to contribute substantially to SOA production, especially in gasoline vehicles with the most advanced aftertreatment. Initial evidence suggests catalyzed diesel particulate filters greatly reduce emissions of SOA precursors along with primary aerosol.
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Affiliation(s)
- Drew R Gentner
- Department of Chemical & Environmental Engineering, Yale University , New Haven, Connecticut 06511, United States
- School of Forestry & Environmental Science, Yale University , New Haven, Connecticut 06511, United States
| | - Shantanu H Jathar
- Department of Mechanical Engineering, Colorado State University , Fort Collins, Colorado 80523, United States
| | - Timothy D Gordon
- Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder, Colorado 80309, United States
- NOAA Earth System Research Laboratory , Boulder, Colorado 80305, United States
| | - Roya Bahreini
- Department of Environmental Sciences, University of California , Riverside, California 92521, United States
| | - Douglas A Day
- Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder, Colorado 80309, United States
- Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States
| | - Imad El Haddad
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute , Villigen, Switzerland
| | - Patrick L Hayes
- Department of Chemistry, Université de Montréal , Montréal, QC, Canada
| | - Simone M Pieber
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute , Villigen, Switzerland
| | - Stephen M Platt
- Department of Atmosphere and Climate, Norwegian Institute for Air Research , 2007 Kjeller, Norway
| | - Joost de Gouw
- Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder, Colorado 80309, United States
- NOAA Earth System Research Laboratory , Boulder, Colorado 80305, United States
| | - Allen H Goldstein
- Department of Environmental Science, Policy and Management, University of California , Berkeley, California 94720, United States
- Department of Civil and Environmental Engineering, University of California , Berkeley, California 94720, United States
| | - Robert A Harley
- Department of Civil and Environmental Engineering, University of California , Berkeley, California 94720, United States
| | - Jose L Jimenez
- Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder, Colorado 80309, United States
- Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States
| | - André S H Prévôt
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute , Villigen, Switzerland
| | - Allen L Robinson
- Department of Mechanical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
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Guo H, Ling ZH, Cheng HR, Simpson IJ, Lyu XP, Wang XM, Shao M, Lu HX, Ayoko G, Zhang YL, Saunders SM, Lam SHM, Wang JL, Blake DR. Tropospheric volatile organic compounds in China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 574:1021-1043. [PMID: 27668854 DOI: 10.1016/j.scitotenv.2016.09.116] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 09/13/2016] [Accepted: 09/15/2016] [Indexed: 06/06/2023]
Abstract
Photochemical smog, characterized by high concentrations of ozone (O3) and fine particles (PM2.5) in the atmosphere, has become one of the top environmental concerns in China. Volatile organic compounds (VOCs), one of the key precursors of O3 and secondary organic aerosol (SOA) (an important component of PM2.5), have a critical influence on atmospheric chemistry and subsequently affect regional and global climate. Thus, VOCs have been extensively studied in many cities and regions in China, especially in the North China Plain, the Yangtze River Delta and the Pearl River Delta regions where photochemical smog pollution has become increasingly worse over recent decades. This paper reviews the main studies conducted in China on the characteristics and sources of VOCs, their relationship with O3 and SOA, and their removal technology. This paper also provides an integrated literature review on the formulation and implementation of effective control strategies of VOCs and photochemical smog, as well as suggestions for future directions of VOCs study in China.
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Affiliation(s)
- H Guo
- Air Quality Studies, Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hong Kong, China.
| | - Z H Ling
- School of Atmospheric Sciences, Sun Yat-sen University, Guangzhou, China
| | - H R Cheng
- School of Resource and Environmental Sciences, Wuhan University, Wuhan, China
| | - I J Simpson
- Department of Chemistry, University of California, Irvine, CA, USA
| | - X P Lyu
- Air Quality Studies, Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hong Kong, China
| | - X M Wang
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
| | - M Shao
- College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - H X Lu
- Air Quality Studies, Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hong Kong, China
| | - G Ayoko
- Discipline of Chemistry, Faculty of Science and Technology, Queensland University of Technology, Australia
| | - Y L Zhang
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
| | - S M Saunders
- School of Chemistry and Biochemistry, University of Western Australia, Perth, Western Australia, Australia
| | - S H M Lam
- Pacific Environment Limited, Perth, Western Australia, Australia
| | - J L Wang
- Department of Chemistry, National Central University, Taiwan
| | - D R Blake
- Department of Chemistry, University of California, Irvine, CA, USA
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49
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Bari MA, Kindzierski WB, Spink D. Twelve-year trends in ambient concentrations of volatile organic compounds in a community of the Alberta Oil Sands Region, Canada. ENVIRONMENT INTERNATIONAL 2016; 91:40-50. [PMID: 26909813 DOI: 10.1016/j.envint.2016.02.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 01/19/2016] [Accepted: 02/10/2016] [Indexed: 06/05/2023]
Abstract
Environmental exposure to volatile organic compounds (VOCs) in ambient air is one of a number of concerns that the First Nation Community of Fort McKay, Alberta has related to development of Canada's oil sands. An in-depth investigation of trends in ambient air VOC levels in Fort McKay was undertaken to better understand the role and possible significance of emissions from Alberta's oil sands development. A non-parametric trend detection method was used to investigate trends in emissions and ambient VOC concentrations over a 12-year (2001-2012) period. Relationships between ambient VOC concentrations and production indicators of oil sands operations around Fort McKay were also examined. A weak upward trend (significant at 90% confidence level) was found for ambient concentrations of total VOCs based on sixteen detected species with an annual increase of 0.64μg/m(3) (7.2%) per year (7.7μg/m(3) increase per decade). Indicators of production (i.e., annual bitumen production and mined oil sands quantities) were correlated with ambient total VOC concentrations. Only one of 29 VOC species evaluated (1-butene) showed a statistically significant upward trend (p=0.05). Observed geometric (arithmetic) mean and maximum ambient concentrations of selected VOCs of public health concern for most recent three years of the study period (2010-2012) were below chronic and acute health risk screening criteria of the U.S. Agency for Toxic Substances and Disease Registry and U.S. Environmental Protection Agency. Thirty-two VOCs are recommended for tracking in future air quality investigations in the community to better understand whether changes are occurring over time in relation to oil sands development activities and to inform policy makers about whether or not these changes warrant additional attention.
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Affiliation(s)
- Md Aynul Bari
- School of Public Health, University of Alberta, 3-57 South Academic Building, 11405-87 Avenue, Edmonton, Alberta T6G 1C9, Canada.
| | - Warren B Kindzierski
- School of Public Health, University of Alberta, 3-57 South Academic Building, 11405-87 Avenue, Edmonton, Alberta T6G 1C9, Canada
| | - David Spink
- Pravid Environmental Inc., 62 Lucerne Crescent, St. Albert, Alberta T8N 2R2, Canada
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50
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Warneke C, Trainer M, de Gouw JA, Parrish DD, Fahey DW, Ravishankara AR, Middlebrook AM, Brock CA, Roberts JM, Brown SS, Neuman JA, Lerner BM, Lack D, Law D, Hübler G, Pollack I, Sjostedt S, Ryerson TB, Gilman JB, Liao J, Holloway J, Peischl J, Nowak JB, Aikin K, Min KE, Washenfelder RA, Graus MG, Richardson M, Markovic MZ, Wagner NL, Welti A, Veres PR, Edwards P, Schwarz JP, Gordon T, Dube WP, McKeen S, Brioude J, Ahmadov R, Bougiatioti A, Lin JJ, Nenes A, Wolfe GM, Hanisco TF, Lee BH, Lopez-Hilfiker FD, Thornton JA, Keutsch FN, Kaiser J, Mao J, Hatch C. Instrumentation and Measurement Strategy for the NOAA SENEX Aircraft Campaign as Part of the Southeast Atmosphere Study 2013. ATMOSPHERIC MEASUREMENT TECHNIQUES 2016; 9:3063-3093. [PMID: 29619117 PMCID: PMC5880326 DOI: 10.5194/amt-9-3063-2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Natural emissions of ozone-and-aerosol-precursor gases such as isoprene and monoterpenes are high in the southeast of the US. In addition, anthropogenic emissions are significant in the Southeast US and summertime photochemistry is rapid. The NOAA-led SENEX (Southeast Nexus) aircraft campaign was one of the major components of the Southeast Atmosphere Study (SAS) and was focused on studying the interactions between biogenic and anthropogenic emissions to form secondary pollutants. During SENEX, the NOAA WP-3D aircraft conducted 20 research flights between 27 May and 10 July 2013 based out of Smyrna, TN. Here we describe the experimental approach, the science goals and early results of the NOAA SENEX campaign. The aircraft, its capabilities and standard measurements are described. The instrument payload is summarized including detection limits, accuracy, precision and time resolutions for all gas-and-aerosol phase instruments. The inter-comparisons of compounds measured with multiple instruments on the NOAA WP-3D are presented and were all within the stated uncertainties, except two of the three NO2 measurements. The SENEX flights included day- and nighttime flights in the Southeast as well as flights over areas with intense shale gas extraction (Marcellus, Fayetteville and Haynesville shale). We present one example flight on 16 June 2013, which was a daytime flight over the Atlanta region, where several crosswind transects of plumes from the city and nearby point sources, such as power plants, paper mills and landfills, were flown. The area around Atlanta has large biogenic isoprene emissions, which provided an excellent case for studying the interactions between biogenic and anthropogenic emissions. In this example flight, chemistry in and outside the Atlanta plumes was observed for several hours after emission. The analysis of this flight showcases the strategies implemented to answer some of the main SENEX science questions.
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Affiliation(s)
- C Warneke
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - M Trainer
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - J A de Gouw
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - D D Parrish
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - D W Fahey
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - A R Ravishankara
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - A M Middlebrook
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - C A Brock
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - J M Roberts
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - S S Brown
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - J A Neuman
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - B M Lerner
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - D Lack
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - D Law
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - G Hübler
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - I Pollack
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - S Sjostedt
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - T B Ryerson
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - J B Gilman
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - J Liao
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - J Holloway
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - J Peischl
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - J B Nowak
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - K Aikin
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - K-E Min
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - R A Washenfelder
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - M G Graus
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - M Richardson
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - M Z Markovic
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - N L Wagner
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - A Welti
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - P R Veres
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - P Edwards
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - J P Schwarz
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - T Gordon
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - W P Dube
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - S McKeen
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - J Brioude
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | - R Ahmadov
- Cooperative Institute for Research in Environmental Sciences, Univ. of Colorado, Boulder
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO
| | | | - J J Lin
- Georgia Institute of Technology, Atlanta, GA
| | - A Nenes
- Georgia Institute of Technology, Atlanta, GA
- Foundation for Research and Technology Hellas, Greece
- National Observatory of Athens, Greece
| | - G M Wolfe
- NASA Goddard Space Flight Center, Greenbelt, MD
- University of Maryland Baltimore County
| | - T F Hanisco
- NASA Goddard Space Flight Center, Greenbelt, MD
| | - B H Lee
- University of Washington, Madison, WI
| | | | | | - F N Keutsch
- University of Wisconsin-Madison, Madison, WI
| | - J Kaiser
- University of Wisconsin-Madison, Madison, WI
| | - J Mao
- Geophysical Fluid Dynamics Laboratory, NOAA, Princeton, NJ
- Princeton University
| | - C Hatch
- Department of Chemistry, Hendrix College, 1600 Washington Ave., Conway, AR, USA
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