Nighttime and daytime dark oxidation chemistry in wildfire plumes: an observation and model analysis of FIREX-AQ aircraft data DOI Creative Commons
Zachary C. J. Decker, Michael Robinson, Kelley C. Barsanti

et al.

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(21), P. 16293 - 16317

Published: Nov. 8, 2021

Abstract. Wildfires are increasing in size across the western US, leading to increases human smoke exposure and associated negative health impacts. The impact of biomass burning (BB) smoke, including wildfires, on regional air quality depends emissions, transport, chemistry, oxidation emitted BB volatile organic compounds (BBVOCs) by hydroxyl radical (OH), nitrate (NO3), ozone (O3). During daytime, when light penetrates plumes, BBVOCs oxidized mainly O3 OH. In contrast, at night or optically dense NO3. This work focuses transition between daytime nighttime oxidation, which has significant implications for formation secondary pollutants loss nitrogen oxides (NOx=NO+NO2) been understudied. We present wildfire plume observations made during FIREX-AQ (Fire Influence Regional Global Environments Air Quality), a field campaign involving multiple aircraft, ground, satellite, mobile platforms that took place United States summer 2019 study both agricultural emissions atmospheric chemistry. use from two research NASA DC-8 NOAA Twin Otter, with detailed chemical box model, updated phenolic mechanisms, analyze sampled midday, sunset, nighttime. Aircraft suggest range NO3 production rates (0.1–1.5 ppbv h−1) plumes transported midday after dark. Modeled initial instantaneous reactivity toward NO3, OH, is 80.1 %, 87.7 99.6 respectively. Initial 10–104 times greater than typical values forested urban environments, reactions account >97 % sunlit (jNO2 up 4×10-3s-1), while conventional photochemical through reaction NO photolysis minor pathways. Alkenes furans mostly OH (11 %–43 54 %–88 alkenes; 18 %–55 39 %–76 furans, respectively), but split O3, (26 %–52 22 16 %–33 respectively). Nitrate accounts 26 sunset an thick plume. Nitrocatechol yields varied 33 45 chemistry late day responsible 72 %–92 (84 plume) nitrocatechol controls nitrophenolic overall. As result, overnight pathways 56 %±2 NOx sunrise following day. all one we modeled, there was remaining (13 %–57 %) (8 %–72 sunrise.

Language: Английский

Formation of secondary organic aerosol from nitrate radical oxidation of phenolic VOCs: Implications for nitration mechanisms and brown carbon formation DOI Creative Commons
Raphael Mayorga, Zixu Zhao, Haofei Zhang

et al.

Atmospheric Environment, Journal Year: 2020, Volume and Issue: 244, P. 117910 - 117910

Published: Sept. 12, 2020

Language: Английский

Citations

98
Volatile Organic Compounds from Logwood Combustion: Emissions and Transformation under Dark and Photochemical Aging Conditions in a Smog Chamber DOI Creative Commons
Anni Hartikainen, Pasi Yli‐Pirilä, Petri Tiitta

et al.

Environmental Science & Technology, Journal Year: 2018, Volume and Issue: 52(8), P. 4979 - 4988

Published: March 8, 2018

Residential wood combustion (RWC) emits high amounts of volatile organic compounds (VOCs) into ambient air, leading to formation secondary aerosol (SOA), and various health climate effects. In this study, the emission factors VOCs from a logwood-fired modern masonry heater were measured using Proton-Transfer-Reactor Time-of-Flight Mass Spectrometer. Next, aged in 29 m3 Teflon chamber equipped with UV black lights, where dark photochemical atmospheric conditions simulated. The main constituents VOC emissions carbonyls aromatic compounds, which accounted for 50%-52% 30%-46% detected emission, respectively. Emissions highly susceptible different conditions, caused 2.4-fold variation factors. overall concentrations declined considerably during both aging, simultaneous increase particulate mass. Especially furanoic phenolic decreased, they are suggested be major precursors RWC-originated SOA all aging conditions. On other hand, produced relatively nitrogen-containing gas phase, while increased especially certain gaseous carbonyls, particularly acid anhydrides.

Language: Английский

Citations

94
Simulation of organic aerosol formation during the CalNex study: updated mobile emissions and secondary organic aerosol parameterization for intermediate-volatility organic compounds DOI Creative Commons

Quanyang Lu,

Benjamin N. Murphy, Momei Qin

et al.

Atmospheric chemistry and physics, Journal Year: 2020, Volume and Issue: 20(7), P. 4313 - 4332

Published: April 14, 2020

Abstract. We describe simulations using an updated version of the Community Multiscale Air Quality model 5.3 (CMAQ v5.3) to investigate contribution intermediate-volatility organic compounds (IVOCs) secondary aerosol (SOA) formation in southern California during CalNex study. first derive a model-ready parameterization for SOA from IVOC emissions mobile sources. To account both diesel and gasoline sources, has six lumped precursor species that resolve volatility molecular structure (aromatic versus aliphatic). also implement new mobile-source emission profiles quantify all IVOCs based on direct measurements. The have been released SPECIATE 5.0. By incorporating comprehensive semivolatile (SVOCs) experimentally constrained yields, this CMAQ configuration best represents sources urban regional ambient (OA). In Los Angeles region, emit 4 times more non-methane gases (NMOGs) than but emits roughly 3 absolute basis. revised predicts (including on- off-road gasoline, aircraft, diesel) contribute ∼1 µg m−3 daily peak concentration Pasadena. This ∼70 % increase predicted compared base CMAQ. Therefore, almost as much traditional precursors such single-ring aromatics. However, accounting these does not reproduce measurements either or IVOCs. potential other we performed two exploratory with varying amounts nonmobile close mass balance primary hydrocarbon IVOCs, would need 12 NMOG (or equivalently 30.7 t d−1 Angeles–Pasadena region), value is well within reported range content volatile chemical products. explain mildly oxygenated Pasadena, additional 14.8 nonmobile-source be (assuming yields apply IVOCs). IVOC-to-NMOG ratio 26.8 68.5 region) likely unrealistically high. Our results highlight important production region underscore uncertainties must addressed (multigenerational aging, aqueous chemistry vapor wall losses) balance. research highlights effectiveness regulations reduce emissions, which turn increased relative importance

Language: Английский

Citations

91
Time-Resolved Intermediate-Volatility and Semivolatile Organic Compound Emissions from Household Coal Combustion in Northern China DOI

Siyi Cai,

Liang Zhu, Shuxiao Wang

et al.

Environmental Science & Technology, Journal Year: 2019, Volume and Issue: 53(15), P. 9269 - 9278

Published: July 10, 2019

Coal combustion in low-efficiency household stoves results the emission of large amounts nonmethane organic compounds (NMOCs), including intermediate-volatility (IVOCs) and semivolatile (SVOCs). This conceptual picture is reasonably well established, however, quantitative assessment I/SVOC emissions from rare. We used a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) to quantify gases typical Chinese coal stove operated with anthracite bituminous coals. Most NMOCs (approximately 64-88%) were dominated by hydrocarbons emitted during ignition flaming phases. The ratio oxidized increased smoldering stages due elevated efficiency. average factors 121 ± 25.7 3690 930 mg/kg for coals, respectively. I/SVOCs contributed approximately 30% total NMOC combustion, much higher than contribution biomass burning 1.5%). Furthermore, may contribute over 70% secondary aerosol (SOA) formed gaseous species as result combustion. study highlights importance inventorying coal-originated when conducting SOA formation simulation studies.

Language: Английский

Citations

80
Nighttime and daytime dark oxidation chemistry in wildfire plumes: an observation and model analysis of FIREX-AQ aircraft data DOI Creative Commons
Zachary C. J. Decker, Michael Robinson, Kelley C. Barsanti

et al.

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(21), P. 16293 - 16317

Published: Nov. 8, 2021

Abstract. Wildfires are increasing in size across the western US, leading to increases human smoke exposure and associated negative health impacts. The impact of biomass burning (BB) smoke, including wildfires, on regional air quality depends emissions, transport, chemistry, oxidation emitted BB volatile organic compounds (BBVOCs) by hydroxyl radical (OH), nitrate (NO3), ozone (O3). During daytime, when light penetrates plumes, BBVOCs oxidized mainly O3 OH. In contrast, at night or optically dense NO3. This work focuses transition between daytime nighttime oxidation, which has significant implications for formation secondary pollutants loss nitrogen oxides (NOx=NO+NO2) been understudied. We present wildfire plume observations made during FIREX-AQ (Fire Influence Regional Global Environments Air Quality), a field campaign involving multiple aircraft, ground, satellite, mobile platforms that took place United States summer 2019 study both agricultural emissions atmospheric chemistry. use from two research NASA DC-8 NOAA Twin Otter, with detailed chemical box model, updated phenolic mechanisms, analyze sampled midday, sunset, nighttime. Aircraft suggest range NO3 production rates (0.1–1.5 ppbv h−1) plumes transported midday after dark. Modeled initial instantaneous reactivity toward NO3, OH, is 80.1 %, 87.7 99.6 respectively. Initial 10–104 times greater than typical values forested urban environments, reactions account >97 % sunlit (jNO2 up 4×10-3s-1), while conventional photochemical through reaction NO photolysis minor pathways. Alkenes furans mostly OH (11 %–43 54 %–88 alkenes; 18 %–55 39 %–76 furans, respectively), but split O3, (26 %–52 22 16 %–33 respectively). Nitrate accounts 26 sunset an thick plume. Nitrocatechol yields varied 33 45 chemistry late day responsible 72 %–92 (84 plume) nitrocatechol controls nitrophenolic overall. As result, overnight pathways 56 %±2 NOx sunrise following day. all one we modeled, there was remaining (13 %–57 %) (8 %–72 sunrise.

Language: Английский

Citations

77