151
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An omnipresent diversity and variability in the chemical composition of atmospheric functionalized organic aerosol. Commun Chem 2018. [DOI: 10.1038/s42004-018-0074-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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152
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Stochastic Transportation Network Considering ATIS with the Information of Environmental Cost. SUSTAINABILITY 2018. [DOI: 10.3390/su10113861] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The environment problem is a sustainable hot topic in the field of transportation research. With higher awareness of the environment problem, travelers tend to choose more environment friendly traffic modes and travel routes. However, for motor vehicle drivers, the environmental cost is an implicit cost, which is not easily perceived. With the help of the advanced traveler information system (ATIS), a fresh scheme was proposed to reduce the environmental cost of the transportation network, which incorporates the information of environmental cost into ATIS to guide drivers to choose more environment-friendly routes. To test the validity of the scheme, we adopted the theory of stochastic network user equilibrium to assign two classes of drivers on the transportation network and analyzed the impact on environmental cost after applying this scheme. Mathematically, a mixed stochastic user equilibrium (SUE) model was proposed to analyze this scheme. The corresponding algorithm was also proposed. Both the model and algorithm were tested in the numerical examples. Through the examples, the validity and feasibility of our proposed scheme were also identified. Our research provided some new ideas for traffic planners and managers to reduce environmental costs caused by traffic.
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153
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Xie LH, Liu XM, He T, Li JR. Metal-Organic Frameworks for the Capture of Trace Aromatic Volatile Organic Compounds. Chem 2018. [DOI: 10.1016/j.chempr.2018.05.017] [Citation(s) in RCA: 160] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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154
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Watne ÅK, Psichoudaki M, Ljungström E, Le Breton M, Hallquist M, Jerksjö M, Fallgren H, Jutterström S, Hallquist ÅM. Fresh and Oxidized Emissions from In-Use Transit Buses Running on Diesel, Biodiesel, and CNG. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:7720-7728. [PMID: 29894174 DOI: 10.1021/acs.est.8b01394] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The potential effect of changing to a nonfossil fuel vehicle fleet was investigated by measuring primary emissions (by extractive sampling of bus plumes) and secondary mass formation, using a Gothenburg Potential Aerosol Mass (Go:PAM) reactor, from 29 in-use transit buses. Regarding fresh emissions, diesel (DSL) buses without a diesel particulate filter (DPF) emitted the highest median mass of particles, whereas compressed natural gas (CNG) buses emitted the lowest (MdEFPM 514 and 11 mg kgfuel-1, respectively). Rapeseed methyl ester (RME) buses showed smaller MdEFPM and particle sizes than DSL buses. DSL (no DPF) and hybrid-electric RME (RMEHEV) buses exhibited the highest particle numbers (MdEFPN 12 × 1014 # kgfuel-1). RMEHEV buses displayed a significant nucleation mode ( Dp< 20 nm). EFPN of CNG buses spanned the highest to lowest values measured. Low MdEFPN and MdEFPM were observed for a DPF-equipped DSL bus. Secondary particle formation resulting from exhaust aging was generally important for all the buses (79% showed an average EFPM:AGED/EFPM:FRESH ratio >10) and fuel types tested, suggesting an important nonfuel dependent source. The results suggest that the potential for forming secondary mass should be considered in future fuel shifts, since the environmental impact is different when only considering the primary emissions.
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Affiliation(s)
- Ågot K Watne
- Department of Chemistry and Molecular Biology, Atmospheric Science , University of Gothenburg , SE-412 96 Gothenburg , Sweden
| | - Magda Psichoudaki
- Department of Chemistry and Molecular Biology, Atmospheric Science , University of Gothenburg , SE-412 96 Gothenburg , Sweden
| | - Evert Ljungström
- Department of Chemistry and Molecular Biology, Atmospheric Science , University of Gothenburg , SE-412 96 Gothenburg , Sweden
| | - Michael Le Breton
- Department of Chemistry and Molecular Biology, Atmospheric Science , University of Gothenburg , SE-412 96 Gothenburg , Sweden
| | - Mattias Hallquist
- Department of Chemistry and Molecular Biology, Atmospheric Science , University of Gothenburg , SE-412 96 Gothenburg , Sweden
| | - Martin Jerksjö
- IVL Swedish Environmental Research Institute , Box 530 21, SE-400 14 Gothenburg , Sweden
| | - Henrik Fallgren
- IVL Swedish Environmental Research Institute , Box 530 21, SE-400 14 Gothenburg , Sweden
| | - Sara Jutterström
- IVL Swedish Environmental Research Institute , Box 530 21, SE-400 14 Gothenburg , Sweden
| | - Åsa M Hallquist
- IVL Swedish Environmental Research Institute , Box 530 21, SE-400 14 Gothenburg , Sweden
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155
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Disentangling vehicular emission impact on urban air pollution using ethanol as a tracer. Sci Rep 2018; 8:10679. [PMID: 30013098 PMCID: PMC6048126 DOI: 10.1038/s41598-018-29138-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 07/04/2018] [Indexed: 11/08/2022] Open
Abstract
The Sao Paulo Metropolitan Area is a unique case worldwide due to the extensive use of biofuel, particularly ethanol, by its large fleet of nearly 8 million cars. Based on source apportionment analysis of Organic Aerosols in downtown Sao Paulo, and using ethanol as tracer of passenger vehicles, we have identified primary emissions from light-duty-vehicles (LDV) and heavy-duty-vehicles (HDV), as well as secondary process component. Each of those factors mirror a relevant primary source or secondary process in this densely occupied area. Using those factors as predictors in a multiple linear regression analysis of a wide range of pollutants, we have quantified the role of primary LDV or HDV emissions, as well as atmospheric secondary processes, on air quality degradation. Results show a significant contribution of HDV emissions, despite contributing only about 5% of vehicles number in the region. The latter is responsible, for example, of 40% and 47% of benzene and black carbon atmospheric concentration, respectively. This work describes an innovative use of biofuel as a tracer of passenger vehicle emissions, allowing to better understand the role of vehicular sources on air quality degradation in one of most populated megacities worldwide.
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156
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Jiang H, Jang M. Dynamic Oxidative Potential of Atmospheric Organic Aerosol under Ambient Sunlight. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:7496-7504. [PMID: 29772167 DOI: 10.1021/acs.est.8b00148] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The atmospheric process dynamically changes the chemical compositions of organic aerosol (OA), thereby complicating the interpretation of its health effects. In this study, the dynamic evolution of the oxidative potential of various OA was studied, including wood combustion particles and secondary organic aerosols (SOA) generated from different hydrocarbons (i.e., gasoline, toluene, isoprene, and α-pinene). The oxidative potential of OA at different aging stages was subsequently measured by the dithiothreitol consumption (DTTm, mass normalized). We hypothesized that DTT consumptions by OA were modulated by catalytic particulate oxidizers (e.g., quinones), noncatalytic particulate oxidizers (e.g., organic hydroperoxides and peroxyacyl nitrates) and electron-deficient alkenes. The results of this study showed that the oxidative potential of OA decreased after an extended period of aging due to the decomposition of particulate oxidizers and electron-deficient alkenes. Quinones (GC-MS data) partially attributed to the DTTm of fresh wood smoke particles but rapidly dropped with aging. In biogenic SOA, organic hydroperoxides (4-nitrophenyl boronic acid assay) exclusively accounted for DTTm and decreased with aging. The DTTm of aromatic SOA, mainly comprising organic hydroperoxides and electron-deficient alkenes (FTIR data), was shortly elevated during the early atmospheric process; however, it showed a noticeable decrease (32-75%) for a long period of aging. We concluded that fresh or moderately aged OA are more reactive to a sulfhydryl group than highly aged OA.
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Affiliation(s)
- Huanhuan Jiang
- Department of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructure and Environment , University of Florida , Gainesville , Florida 32608 , United States
| | - Myoseon Jang
- Department of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructure and Environment , University of Florida , Gainesville , Florida 32608 , United States
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157
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Saha PK, Reece SM, Grieshop AP. Seasonally Varying Secondary Organic Aerosol Formation From In-Situ Oxidation of Near-Highway Air. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:7192-7202. [PMID: 29847110 DOI: 10.1021/acs.est.8b01134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The extent to which motor vehicles contribute to ambient secondary organic aerosol (SOA) remains uncertain. Here, we present in situ measurements of SOA formation at a near-highway site with substantial tree-cover 10 m from Interstate 40 near Durham, North Carolina. In July 2015 (summer) and February 2016 (winter), we exposed ambient air to a range of oxidant (O3 and OH) concentrations in an oxidation flow reactor (OFR), resulting in hours to weeks of equivalent atmospheric aging. We observed substantial seasonal variation in SOA formation upon OFR aging; diurnally varying OA enhancements of ∼3-8 μg m-3 were observed in summer and significantly lower enhancements (∼0.5-1 μg m-3) in winter. Measurements in both seasons showed consistent changes in bulk OA properties (chemical composition; volatility) with OFR aging. Mild increases in traffic-related SOA precursors during summer partly explains the seasonal variation. However, biogenic emissions, with sharp temperature dependence, appear to dominate summer OFR-SOA. Our analysis indicates that SOA observed in the OFR is similar (within a factor of 2) to that predicted to form from traffic and biogenic precursors using literature yields, especially in winter. This study highlights the utility of the OFR for studying the prevalence of SOA precursors in complex real-world settings.
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Affiliation(s)
- Provat K Saha
- Department of Civil, Construction and Environmental Engineering , North Carolina State University , 431B Mann Hall , Raleigh , North Carolina 27695 , United States
| | - Stephen M Reece
- Department of Civil, Construction and Environmental Engineering , North Carolina State University , 431B Mann Hall , Raleigh , North Carolina 27695 , United States
| | - Andrew P Grieshop
- Department of Civil, Construction and Environmental Engineering , North Carolina State University , 431B Mann Hall , Raleigh , North Carolina 27695 , United States
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158
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Simon MC, Patton AP, Naumova EN, Levy JI, Kumar P, Brugge D, Durant JL. Combining Measurements from Mobile Monitoring and a Reference Site To Develop Models of Ambient Ultrafine Particle Number Concentration at Residences. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:6985-6995. [PMID: 29762018 PMCID: PMC8371457 DOI: 10.1021/acs.est.8b00292] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Significant spatial and temporal variation in ultrafine particle (UFP; <100 nm in diameter) concentrations creates challenges in developing predictive models for epidemiological investigations. We compared the performance of land-use regression models built by combining mobile and stationary measurements (hybrid model) with a regression model built using mobile measurements only (mobile model) in Chelsea and Boston, MA (USA). In each study area, particle number concentration (PNC; a proxy for UFP) was measured at a stationary reference site and with a mobile laboratory driven along a fixed route during an ∼1-year monitoring period. In comparing PNC measured at 20 residences and PNC estimates from hybrid and mobile models, the hybrid model showed higher Pearson correlations of natural log-transformed PNC ( r = 0.73 vs 0.51 in Chelsea; r = 0.74 vs 0.47 in Boston) and lower root-mean-square error in Chelsea (0.61 vs 0.72) but no benefit in Boston (0.72 vs 0.71). All models overpredicted log-transformed PNC by 3-6% at residences, yet the hybrid model reduced the standard deviation of the residuals by 15% in Chelsea and 31% in Boston with better tracking of overnight decreases in PNC. Overall, the hybrid model considerably outperformed the mobile model and could offer reduced exposure error for UFP epidemiology.
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Affiliation(s)
- Matthew C. Simon
- Department of Environmental Health, Boston University School of Public Health, 715 Albany Street, Boston, Massachusetts 02118, United States
- Department of Civil and Environmental Engineering, Tufts University, 200 College Avenue, Medford, Massachusetts 02155, United States
- Corresponding Author:
| | - Allison P. Patton
- Health Effects Institute, 75 Federal Street, Suite 1400, Boston, Massachusetts 02110, United States
| | - Elena N. Naumova
- Department of Civil and Environmental Engineering, Tufts University, 200 College Avenue, Medford, Massachusetts 02155, United States
- Friedman School of Nutrition Science and Policy, Tufts University, 150 Harrison Avenue, Boston, Massachusetts 02111, United States
| | - Jonathan I. Levy
- Department of Environmental Health, Boston University School of Public Health, 715 Albany Street, Boston, Massachusetts 02118, United States
| | - Prashant Kumar
- Global Centre for Clean Air Research (GCARE), Department of Civil and Environmental Engineering, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - Doug Brugge
- Department of Civil and Environmental Engineering, Tufts University, 200 College Avenue, Medford, Massachusetts 02155, United States
- Department of Public Health and Community Medicine, Tufts University, 136 Harrison Avenue, Boston, Massachusetts 02111, United States
- Jonathan M. Tisch College of Civil Life, Tufts University, 10 Upper Campus Road, Medford, Massachusetts 02155, United States
| | - John L. Durant
- Department of Civil and Environmental Engineering, Tufts University, 200 College Avenue, Medford, Massachusetts 02155, United States
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159
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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: 352] [Impact Index Per Article: 58.7] [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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160
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Li K, Chen L, White SJ, Yu H, Wu X, Gao X, Azzi M, Cen K. Smog chamber study of the role of NH 3 in new particle formation from photo-oxidation of aromatic hydrocarbons. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 619-620:927-937. [PMID: 29734638 DOI: 10.1016/j.scitotenv.2017.11.180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/20/2017] [Accepted: 11/16/2017] [Indexed: 06/08/2023]
Abstract
Ammonia (NH3) is a major contributor to secondary aerosol in the atmosphere and can alter the kinetics of their formation. However, systematic studies related to the role of NH3 in aerosol nucleation processes and further particle size growth under complex scenarios are lacking. In this study, we conducted 16 experiments in the CSIRO smog chamber under dry conditions using aromatic hydrocarbons (toluene, o-/m-/p-xylene) and different concentrations of NH3. The presence of NH3 did not change the gas-phase chemistry or nucleation onset time, but slowed the nucleation rate (5%-94%) once it began. From the response of nitrogen oxides (NOx) measurement and mechanism modeling results, we hypothesised that the surface reaction between NH3 and nitric acid played a central role in aerosol nucleation and further growth. After nucleation, the subsequently formed ammonium nitrate and organic condensation vapours may partition together into the initial growth process of new particles, thus increasing the aerosol initial growth rate (8%-90%) and size growth potentials (7%-108%), and leading to high aerosol mass formation. Further investigation implied that the initial growth and further growth rate determine the aerosol mass concentration, rather than the nucleation rate. We conclude that both the initial NOx concentration and volatile organic compound (VOC)/NOx ratio are crucial for the initial and further growth, and aerosol mass of new particles, when NH3 levels are high. Our results provide crucial insights into the complex chemistry of VOC/NOx/NH3 in the atmosphere, and highlight the importance of NH3 reduction for particulate matter control.
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Affiliation(s)
- Kangwei Li
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China; CSIRO Energy, PO Box 52, North Ryde, NSW 1670, Australia
| | - Linghong Chen
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China.
| | | | - Hai Yu
- CSIRO Energy, 10 Murray Dwyer Circuit, Mayfield West, NSW 2304, Australia
| | - Xuecheng Wu
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Xiang Gao
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Merched Azzi
- CSIRO Energy, PO Box 52, North Ryde, NSW 1670, Australia
| | - Kefa Cen
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
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161
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Tessum MW, Larson T, Gould TR, Simpson CD, Yost MG, Vedal S. Mobile and Fixed-Site Measurements To Identify Spatial Distributions of Traffic-Related Pollution Sources in Los Angeles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:2844-2853. [PMID: 29382190 PMCID: PMC5843188 DOI: 10.1021/acs.est.7b04889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Mobile monitoring and fixed-site monitoring using passive sampling devices (PSD) are popular air pollutant measurement techniques with complementary strengths and weaknesses. This study investigates the utility of combining data from concurrent 2-week mobile monitoring and fixed-site PSD campaigns in Los Angeles in the summer and early spring to identify sources of traffic-related air pollutants (TRAP) and their spatial distributions. There were strong to moderate correlations between mobile and fixed-site PSD measurements of both NO2 and NO x in the summer and spring (Pearson's r between 0.43 and 0.79), suggesting that the two data sets can be reliably combined for source apportionment. PCA identified the major TRAP sources as light-duty vehicle emissions, diesel exhaust, crankcase vent emissions, and an independent source of combustion-derived ultrafine particle emissions. The component scores of those four sources at each site were significantly correlated across the two seasons (Pearson's r between 0.58 and 0.79). Spatial maps of absolute principal component scores showed all sources to be most prominent near major roadways and the central business district and the ultrafine particle source being, in addition, more prominent near the airport. Mobile monitoring combined with fixed-site PSD sampling can provide high spatial resolution estimates of TRAP and can reveal underlying sources of exposure variability.
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Affiliation(s)
- Mei W. Tessum
- Department of Environmental and Occupational Health Sciences, University of Washington, Box 357234, Seattle, Washington 98198, United States
| | - Timothy Larson
- Department of Environmental and Occupational Health Sciences, University of Washington, Box 357234, Seattle, Washington 98198, United States
- Department of Civil & Environmental Engineering, University of Washington, Box 352700, Seattle, Washington 98198, United States
| | - Timothy R. Gould
- Department of Civil & Environmental Engineering, University of Washington, Box 352700, Seattle, Washington 98198, United States
| | - Christopher D. Simpson
- Department of Environmental and Occupational Health Sciences, University of Washington, Box 357234, Seattle, Washington 98198, United States
| | - Michael G. Yost
- Department of Environmental and Occupational Health Sciences, University of Washington, Box 357234, Seattle, Washington 98198, United States
| | - Sverre Vedal
- Department of Environmental and Occupational Health Sciences, University of Washington, Box 357234, Seattle, Washington 98198, United States
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162
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Zhao Y, Lambe AT, Saleh R, Saliba G, Robinson AL. Secondary Organic Aerosol Production from Gasoline Vehicle Exhaust: Effects of Engine Technology, Cold Start, and Emission Certification Standard. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:1253-1261. [PMID: 29303572 DOI: 10.1021/acs.est.7b05045] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Secondary organic aerosol (SOA) formation from dilute exhaust from 16 gasoline vehicles was investigated using a potential aerosol mass (PAM) oxidation flow reactor during chassis dynamometer testing using the cold-start unified cycle (UC). Ten vehicles were equipped with gasoline direct injection engines (GDI vehicles) and six with port fuel injection engines (PFI vehicles) certified to a wide range of emissions standards. We measured similar SOA production from GDI and PFI vehicles certified to the same emissions standard; less SOA production from vehicles certified to stricter emissions standards; and, after accounting for differences in gas-particle partitioning, similar effective SOA yields across different engine technologies and certification standards. Therefore the ongoing, dramatic shift from PFI to GDI vehicles in the United States should not alter the contribution of gasoline vehicles to ambient SOA and the natural replacement of older vehicles with newer ones certified to stricter emissions standards should reduce atmospheric SOA levels. Compared to hot operations, cold-start exhaust had lower effective SOA yields, but still contributed more SOA overall because of substantially higher organic gas emissions. We demonstrate that the PAM reactor can be used as a screening tool for vehicle SOA production by carefully accounting for the effects of the large variations in emission rates.
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Affiliation(s)
- Yunliang Zhao
- Department of Mechanical Engineering and Center for Atmospheric Particle Studies, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Andrew T Lambe
- Aerodyne Research Inc., Billerica, Massachusetts 01821, United States
| | - Rawad Saleh
- Department of Mechanical Engineering and Center for Atmospheric Particle Studies, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Georges Saliba
- Department of Mechanical Engineering and Center for Atmospheric Particle Studies, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Allen L Robinson
- Department of Mechanical Engineering and Center for Atmospheric Particle Studies, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
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163
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Xu J, Huang MQ, Cai SY, Liao YM, Hu CJ, Zhao WX, Gu XJ, Zhang WJ. Chemical Composition and Reaction Mechanisms for Aged p
-Xylene Secondary Organic Aerosol in the Presence of Ammonia. J CHIN CHEM SOC-TAIP 2018. [DOI: 10.1002/jccs.201700249] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jun Xu
- Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, College of Chemistry & Environment; Minnan Normal University; Zhangzhou 363000 P. R. China
| | - Ming-Qiang Huang
- Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, College of Chemistry & Environment; Minnan Normal University; Zhangzhou 363000 P. R. China
- College of Environmental Science and Engineering, Xiamen University; Tan Kah Kee College; Zhangzhou 363105 P. R. China
| | - Shun-You Cai
- Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, College of Chemistry & Environment; Minnan Normal University; Zhangzhou 363000 P. R. China
| | - Ying-Min Liao
- College of Environmental Science and Engineering, Xiamen University; Tan Kah Kee College; Zhangzhou 363105 P. R. China
| | - Chang-Jin Hu
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics; Chinese Academy of Sciences; Hefei 230031 P. R. China
| | - Wei-Xiong Zhao
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics; Chinese Academy of Sciences; Hefei 230031 P. R. China
| | - Xue-Jun Gu
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics; Chinese Academy of Sciences; Hefei 230031 P. R. China
| | - Wei-Jun Zhang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics; Chinese Academy of Sciences; Hefei 230031 P. R. China
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164
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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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165
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Kalume A, Wang C, Santarpia J, Pan YL. Liquid–liquid phase separation and evaporation of a laser-trapped organic–organic airborne droplet using temporal spatial-resolved Raman spectroscopy. Phys Chem Chem Phys 2018; 20:19151-19159. [DOI: 10.1039/c8cp02372g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Using temporal position-resolved Raman spectroscopy, different gradient distributions of two chemicals an different time within an airborne droplets were directly observed, as well as their phase separation and evaporation processes.
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Affiliation(s)
| | - Chuji Wang
- Mississippi State University
- Starkville
- USA
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166
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Grant JS, Shaw SK. A model system to mimic environmentally active surface film roughness and hydrophobicity. CHEMOSPHERE 2017; 185:772-779. [PMID: 28735233 DOI: 10.1016/j.chemosphere.2017.07.068] [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: 04/14/2017] [Revised: 06/28/2017] [Accepted: 07/13/2017] [Indexed: 06/07/2023]
Abstract
This work presents the development and initial assessment of a laboratory platform to allow quantitative studies on model urban films. The platform consists of stearic acid and eicosane mixtures that are solution deposited from hexanes onto smooth, solid substrates. We show that this model has distinctive capabilities to better mimic a naturally occurring film's morphology and hydrophobicity, two important parameters that have not previously been incorporated into model film systems. The physical and chemical properties of the model films are assessed using a variety of analytical instruments. The film thickness and roughness are probed via atomic force microscopy while the film composition, wettability, and water uptake are analyzed by Fourier transform infrared spectroscopy, contact angle goniometry, and quartz crystal microbalance, respectively. Simulated environmental maturation is achieved by exposing the film to regulated amounts of UV/ozone. Ultimately, oxidation of the film is monitored by the analytical techniques mentioned above and proceeds as expected to produce a utile model film system. Including variable roughness and tunable surface coverage results in several key advantages over prior model systems, and will more accurately represent native urban film behavior.
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167
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Friedman B, Link MF, Fulgham SR, Brophy P, Galang A, Brune WH, Jathar SH, Farmer DK. Primary and Secondary Sources of Gas-Phase Organic Acids from Diesel Exhaust. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:10872-10880. [PMID: 28825297 DOI: 10.1021/acs.est.7b01169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Organic acids have primary and secondary sources in the atmosphere, impact ecosystem health, and are useful metrics for identifying gaps in organic oxidation chemistry through model-measurement comparisons. We photooxidized (OH oxidation) primary emissions from diesel and biodiesel fuel types under two engine loads in an oxidative flow reactor. formic, butyric, and propanoic acids, but not methacrylic acid, have primary and secondary sources. Emission factors for these gas-phase acids varied from 0.3-8.4 mg kg-1 fuel. Secondary chemistry enhanced these emissions by 1.1 (load) to 4.4 (idle) × after two OH-equivalent days. The relative enhancement in secondary organic acids in idle versus loaded conditions was due to increased precursor emissions, not faster reaction rates. Increased hydrocarbon emissions in idle conditions due to less complete combustion (associated with less oxidized gas-phase molecules) correlated to higher primary organic acid emissions. The lack of correlation between organic aerosol and organic acid concentrations downstream of the flow reactor indicates that the secondary products formed on different oxidation time scales and that despite being photochemical products, organic acids are poor tracers for secondary organic aerosol formation from diesel exhaust. Ignoring secondary chemistry from diesel exhaust would lead to underestimates of both organic aerosol and gas-phase organic acids.
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Affiliation(s)
- Beth Friedman
- Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523-1872, United States
| | - Michael F Link
- Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523-1872, United States
| | - S Ryan Fulgham
- Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523-1872, United States
| | - Patrick Brophy
- Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523-1872, United States
| | - Abril Galang
- Department of Mechanical Engineering, Colorado State University , Fort Collins, Colorado 80523-1872, United States
| | - William H Brune
- Department of Meteorology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Shantanu H Jathar
- Department of Mechanical Engineering, Colorado State University , Fort Collins, Colorado 80523-1872, United States
| | - Delphine K Farmer
- Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523-1872, United States
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168
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Characterizing particulate polycyclic aromatic hydrocarbon emissions from diesel vehicles using a portable emissions measurement system. Sci Rep 2017; 7:10058. [PMID: 28855647 PMCID: PMC5577249 DOI: 10.1038/s41598-017-09822-w] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/31/2017] [Indexed: 11/30/2022] Open
Abstract
Particulate polycyclic aromatic hydrocarbons (p-PAHs) emitted from diesel vehicles are of concern because of their significant health impacts. Laboratory tests, road tunnel and roadside experiments have been conducted to measure p-PAH emissions. While providing valuable information, these methods have limited capabilities of characterizing p-PAH emissions either from individual vehicles or under real-world conditions. We employed a portable emissions measurement (PEMS) to measure real-world emission factors of priority p-PAHs for diesel vehicles representative of an array of emission control technologies. The results indicated over 80% reduction in p-PAH emission factors comparing the China V and China II emission standard groups (113 μg kg−1 vs. 733 μg kg−1). The toxicity abatement in terms of Benzo[a]pyrene equivalent emissions was substantial because of the large reductions in highly toxic components. By assessing real traffic conditions, the p-PAH emission factors on freeways were lower than on local roads by 52% ± 24%. A significant correlation (R2~0.85) between the p-PAH and black carbon emissions was identified with a mass ratio of approximately 1/2000. A literature review indicated that diesel p-PAH emission factors varied widely by engine technology, measurement methods and conditions, and the molecular diagnostic ratio method for source apportionment should be used with great caution.
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169
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Platt SM, El Haddad I, Pieber SM, Zardini AA, Suarez-Bertoa R, Clairotte M, Daellenbach KR, Huang RJ, Slowik JG, Hellebust S, Temime-Roussel B, Marchand N, de Gouw J, Jimenez JL, Hayes PL, Robinson AL, Baltensperger U, Astorga C, Prévôt ASH. Gasoline cars produce more carbonaceous particulate matter than modern filter-equipped diesel cars. Sci Rep 2017; 7:4926. [PMID: 28706240 PMCID: PMC5509693 DOI: 10.1038/s41598-017-03714-9] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 05/10/2017] [Indexed: 11/17/2022] Open
Abstract
Carbonaceous particulate matter (PM), comprising black carbon (BC), primary organic aerosol (POA) and secondary organic aerosol (SOA, from atmospheric aging of precursors), is a highly toxic vehicle exhaust component. Therefore, understanding vehicle pollution requires knowledge of both primary emissions, and how these emissions age in the atmosphere. We provide a systematic examination of carbonaceous PM emissions and parameterisation of SOA formation from modern diesel and gasoline cars at different temperatures (22, -7 °C) during controlled laboratory experiments. Carbonaceous PM emission and SOA formation is markedly higher from gasoline than diesel particle filter (DPF) and catalyst-equipped diesel cars, more so at -7 °C, contrasting with nitrogen oxides (NOX). Higher SOA formation from gasoline cars and primary emission reductions for diesels implies gasoline cars will increasingly dominate vehicular total carbonaceous PM, though older non-DPF-equipped diesels will continue to dominate the primary fraction for some time. Supported by state-of-the-art source apportionment of ambient fossil fuel derived PM, our results show that whether gasoline or diesel cars are more polluting depends on the pollutant in question, i.e. that diesel cars are not necessarily worse polluters than gasoline cars.
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Affiliation(s)
- S M Platt
- Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, CH-5232, Villigen, Switzerland
- NILU-Norwegian Institute for Air Research, PO Box 100, 2027, Kjeller, Norway
| | - I El Haddad
- Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, CH-5232, Villigen, Switzerland.
| | - S M Pieber
- Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, CH-5232, Villigen, Switzerland
| | - A A Zardini
- European Commission Joint Research Centre, Directorate for Energy, Transport and Climate, Sustainable Transport Unit, 21027, Ispra, (VA), Italy
| | - R Suarez-Bertoa
- European Commission Joint Research Centre, Directorate for Energy, Transport and Climate, Sustainable Transport Unit, 21027, Ispra, (VA), Italy
| | - M Clairotte
- European Commission Joint Research Centre, Directorate for Energy, Transport and Climate, Sustainable Transport Unit, 21027, Ispra, (VA), Italy
| | - K R Daellenbach
- Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, CH-5232, Villigen, Switzerland
| | - R-J Huang
- Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, CH-5232, Villigen, Switzerland
- Key Laboratory of Aerosol Chemistry & Physics, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China
| | - J G Slowik
- Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, CH-5232, Villigen, Switzerland
| | - S Hellebust
- Aix Marseille Univ, CNRS, LCE, Marseille, France
- Central Statistics Office, Cork, Ireland
| | | | - N Marchand
- Aix Marseille Univ, CNRS, LCE, Marseille, France
| | - J de Gouw
- NOAA Earth System Research Laboratory, Boulder, CO, USA
- CIRES, University of Colorado, Boulder, CO, USA
| | - J L Jimenez
- CIRES, University of Colorado, Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
| | - P L Hayes
- Département de Chimie, Université de Montréal, Montréal, Québec, Canada
| | - A L Robinson
- Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - U Baltensperger
- Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, CH-5232, Villigen, Switzerland
| | - C Astorga
- European Commission Joint Research Centre, Directorate for Energy, Transport and Climate, Sustainable Transport Unit, 21027, Ispra, (VA), Italy
| | - A S H Prévôt
- Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, CH-5232, Villigen, Switzerland.
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170
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Haugen MJ, Bishop GA. Repeat Fuel Specific Emission Measurements on Two California Heavy-Duty Truck Fleets. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:4100-4107. [PMID: 28290679 DOI: 10.1021/acs.est.6b06172] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The University of Denver repeated its 2013 fuel specific gaseous and particle emission measurements on two California heavy-duty vehicle fleets. In 2015 1456 measurements at the Port of Los Angeles and 694 measurements at the Cottonwood weigh station in northern California were collected. The Port fleet changed little since 2013, increasing the average age (+1.8 years), accompanied by an increase in particle mass (PM) by +266% (0.03 ± 0.01 to 0.11 ± 0.01 gPM/kg of fuel) and black carbon (BC) by +300% (0.02 ± 0.003 to 0.08 ± 0.01 gBC/kg of fuel). Particle number (PN) also increased (1.5 × 1014 ± 2.5 × 1013 to 2.8 × 1014 ± 2.8 × 1013 PN/kg of fuel) by a smaller percentage (+87%). Chassis model year 2008 and 2009 vehicles currently dominate the fleet, accounting for the majority of these increases. The long-haul Cottonwood fleet decreased in fleet age (-0.6 model years), where half the decreases in fuel specific PM (-66%), BC (-65%), and PN (-19%) emissions are due to the newer fleet; an increased fraction of pre-2008 chassis model year vehicles with retrofit diesel particulate filters (DPFs) account for the remaining reductions. These opposing emissions trends emphasize the importance of fully functional DPFs.
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Affiliation(s)
- Molly J Haugen
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208, United States
| | - Gary A Bishop
- Department of Chemistry and Biochemistry, University of Denver , Denver, Colorado 80208, United States
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