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Sekimoto K, Coggon MM, Gkatzelis GI, Stockwell CE, Peischl J, Soja AJ, Warneke C. Fuel-Type Independent Parameterization of Volatile Organic Compound Emissions from Western US Wildfires. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:13193-13204. [PMID: 37611137 PMCID: PMC10483695 DOI: 10.1021/acs.est.3c00537] [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: 01/19/2023] [Revised: 08/04/2023] [Accepted: 08/04/2023] [Indexed: 08/25/2023]
Abstract
Volatile organic compounds (VOCs) emitted from biomass burning impact air quality and climate. Laboratory studies have shown that the variability in VOC speciation is largely driven by changes in combustion conditions and is only modestly impacted by fuel type. Here, we report that emissions of VOCs measured in ambient smoke emitted from western US wildfires can be parameterized by high- and low-temperature pyrolysis VOC profiles and are consistent with previous observations from laboratory simulated fires. This is demonstrated using positive matrix factorization (PMF) constrained by high- and low-temperature factors using VOC measurements obtained with a proton-transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS) on board the NASA DC-8 during the FIREX-AQ (Fire Influence on Regional and Global Environments and Air Quality) project in 2019. A linear combination of high- and low-temperature factors described more than 70% of the variability of VOC emissions of long-lived VOCs in all sampled wildfire plumes. An additional factor attributable to atmospheric aging was required to parameterize short-lived and secondarily produced VOCs. The relative contribution of the PMF-derived high-temperature factor for a given fire plume was strongly correlated with the fire radiative power (FRP) at the estimated time of emission detected by satellite measurements. By combining the FRP with the fraction of the high-temperature PMF factor, the emission ratios (ERs) of VOCs to carbon monoxide (CO) in fresh wildfires were estimated and agree well with measured ERs (r2 = 0.80-0.93).
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Affiliation(s)
- Kanako Sekimoto
- Graduate
School of Nanobioscience, Yokohama City
University, Yokohama, Kanagawa 236-0027, Japan
| | - Matthew M. Coggon
- NOAA
Chemical Sciences Laboratory, Boulder, Corolado 80305, United States
| | - Georgios I. Gkatzelis
- NOAA
Chemical Sciences Laboratory, Boulder, Corolado 80305, United States
- Cooperative
Institute for Research in Environmental Sciences, University of Colorado
Boulder, Boulder, Colorado 80309, United States
| | - Chelsea E. Stockwell
- NOAA
Chemical Sciences Laboratory, Boulder, Corolado 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, Corolado 80305, United States
- Cooperative
Institute for Research in Environmental Sciences, University of Colorado
Boulder, Boulder, Colorado 80309, United States
| | - Amber J. Soja
- National
Institute of Aerospace, Hampton, Virginia 23666, United States
- NASA
Langley Research Center, Hampton, Virginia 23681, United States
| | - Carsten Warneke
- NOAA
Chemical Sciences Laboratory, Boulder, Corolado 80305, United States
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Peng Q, Palm BB, Melander KE, Lee BH, Hall SR, Ullmann K, Campos T, Weinheimer AJ, Apel EC, Hornbrook RS, Hills AJ, Montzka DD, Flocke F, Hu L, Permar W, Wielgasz C, Lindaas J, Pollack IB, Fischer EV, Bertram TH, Thornton JA. HONO Emissions from Western U.S. Wildfires Provide Dominant Radical Source in Fresh Wildfire Smoke. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:5954-5963. [PMID: 32294377 DOI: 10.1021/acs.est.0c00126] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Wildfires are an important source of nitrous acid (HONO), a photolabile radical precursor, yet in situ measurements and quantification of primary HONO emissions from open wildfires have been scarce. We present airborne observations of HONO within wildfire plumes sampled during the Western Wildfire Experiment for Cloud chemistry, Aerosol absorption and Nitrogen (WE-CAN) campaign. ΔHONO/ΔCO close to the fire locations ranged from 0.7 to 17 pptv ppbv-1 using a maximum enhancement method, with the median similar to previous observations of temperate forest fire plumes. Measured HONO to NOx enhancement ratios were generally factors of 2, or higher, at early plume ages than previous studies. Enhancement ratios scale with modified combustion efficiency and certain nitrogenous trace gases, which may be useful to estimate HONO release when HONO observations are lacking or plumes have photochemical exposures exceeding an hour as emitted HONO is rapidly photolyzed. We find that HONO photolysis is the dominant contributor to hydrogen oxide radicals (HOx = OH + HO2) in early stage (<3 h) wildfire plume evolution. These results highlight the role of HONO as a major component of reactive nitrogen emissions from wildfires and the main driver of initial photochemical oxidation.
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Affiliation(s)
- Qiaoyun Peng
- Department of Atmospheric Sciences, University of Washington, Seattle, Washington 98195, United States
| | - Brett B Palm
- Department of Atmospheric Sciences, University of Washington, Seattle, Washington 98195, United States
| | - Kira E Melander
- Department of Atmospheric Sciences, University of Washington, Seattle, Washington 98195, United States
| | - Ben H Lee
- Department of Atmospheric Sciences, University of Washington, Seattle, Washington 98195, United States
| | - Samuel R Hall
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, Colorado 80301, United States
| | - Kirk Ullmann
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, Colorado 80301, United States
| | - Teresa Campos
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, Colorado 80301, United States
| | - Andrew J Weinheimer
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, Colorado 80301, United States
| | - Eric C Apel
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, Colorado 80301, United States
| | - Rebecca S Hornbrook
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, Colorado 80301, United States
| | - Alan J Hills
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, Colorado 80301, United States
| | - Denise D Montzka
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, Colorado 80301, United States
| | - Frank Flocke
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, Colorado 80301, United States
| | - Lu Hu
- Department of Chemistry and Biochemistry, University of Montana, Missoula, Montana 59812, United States
| | - Wade Permar
- Department of Chemistry and Biochemistry, University of Montana, Missoula, Montana 59812, United States
| | - Catherine Wielgasz
- Department of Chemistry and Biochemistry, University of Montana, Missoula, Montana 59812, United States
| | - Jakob Lindaas
- Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Ilana B Pollack
- Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Emily V Fischer
- Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Timothy H Bertram
- Department of Chemistry, University of Wisconsin, Madison Wisconsin 53706, United States
| | - Joel A Thornton
- Department of Atmospheric Sciences, University of Washington, Seattle, Washington 98195, United States
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3
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Buysse CE, Kaulfus A, Nair U, Jaffe DA. Relationships between Particulate Matter, Ozone, and Nitrogen Oxides during Urban Smoke Events in the Western US. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:12519-12528. [PMID: 31597429 DOI: 10.1021/acs.est.9b05241] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Urban ozone (O3) pollution is influenced by the transport of wildfire smoke but observed impacts are highly variable. We investigate O3 impacts from smoke in 18 western US cities during July-September, 2013-2017, with ground-based monitoring data from air quality system sites, using satellite-based hazard mapping system (HMS) fire and smoke product to identify overhead smoke. We present four key findings. First, O3 and PM2.5 (particulate matter <2.5 μm in diameter) are elevated at nearly all sites on days influenced by smoke, with the greatest mean enhancement occurring during multiday smoke events; nitrogen oxides (NOx) are not consistently elevated across all sites. Second, PM2.5 and O3 exhibit a nonlinear relationship such that O3 increases with PM2.5 at low to moderate 24 h PM2.5, peaks around 30-50 μg m-3, and declines at higher PM2.5. Third, the rate of increase of morning O3 is higher and NO/NO2 ratios are lower on smoke-influenced days, which could result from additional atmospheric oxidants in smoke. Fourth, while the HMS product is a useful tool for identifying smoke, O3 and PM2.5 are elevated on days before and after HMS-identified smoke events implying that a significant fraction of smoke events is not detected.
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Affiliation(s)
- Claire E Buysse
- Department of Atmospheric Sciences , University of Washington , Seattle , Washington 98195 , United States
| | - Aaron Kaulfus
- Department of Atmospheric Science , University of Alabama in Huntsville , Huntsville , Alabama 35899 , United States
| | - Udaysankar Nair
- Department of Atmospheric Science , University of Alabama in Huntsville , Huntsville , Alabama 35899 , United States
| | - Daniel A Jaffe
- Department of Atmospheric Sciences , University of Washington , Seattle , Washington 98195 , United States
- School of Science, Technology, Engineering, and Mathematics , University of Washington-Bothell , Bothell , Washington 98011 , United States
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Abstract
Soot particles produced by incomplete combustion processes are one of the major components of urban air pollution. Chemistry at their surfaces lead to the heterogeneous conversion of several key trace gases; for example NO(2) interacts with soot and is converted into HONO, which rapidly photodissociates to form OH in the troposphere. In the dark, soot surfaces are rapidly deactivated under atmospheric conditions, leading to the current understanding that soot chemistry affects tropospheric chemical composition only in a minor way. We demonstrate here that the conversion of NO(2) to HONO on soot particles is drastically enhanced in the presence of artificial solar radiation, and leads to persistent reactivity over long periods. Soot photochemistry may therefore be a key player in urban air pollution.
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