Aging of Volatile Organic Compounds in October 2017 Northern California Wildfire Plumes

Environmental Science & Technology, Год журнала: 2022, Номер 56(3), С. 1557 - 1567

Опубликована: Янв. 17, 2022

In the western United States, number and severity of large wildfires have been growing for decades. Biomass burning (BB) is a major source volatile organic compounds (VOCs) to atmosphere both globally regionally. Following emission, BB VOCs are oxidized while being transported downwind, producing ozone, secondary aerosols, hazardous VOCs. this research, we measured using proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS) in an urban area 55–65 km downwind October 2017 Northern California wildfires. Nonaromatic oxygenated were dominant component measured. smoke plumes, account 70–75% total observed carbon, with remainder particulate matter (with diameter <2.5 μm, PM2.5). We show that correlation furan (primary VOC) maleic anhydride (secondary can indicate origin This was further confirmed by diurnal variations their concentration-weighted trajectories. Oxidation during transport consumed highly reactive including benzenoids, furanoids, terpenoids produced more Furthermore, wildfire altered ozone formation regime raised O3 levels San Francisco Bay Area.

Язык: Английский

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Unexpected High Contribution of Residential Biomass Burning to Non‐Methane Organic Gases (NMOGs) in the Yangtze River Delta Region of China

Journal of Geophysical Research Atmospheres, Год журнала: 2022, Номер 127(4)

Опубликована: Янв. 24, 2022

Abstract Residential biomass burning (BB) plays an important role in the generation of household energy rural China and can contribute to degradation regional air quality. Here, unexpectedly strong residential BB emissions were identified during EXPeriment on eLucidation atmospheric Oxidation capacity aerosol foRmation, their Effects Yangtze River Delta (YRD) campaign area Eastern based early summertime measurements non‐methane organic gases (NMOGs) by a Proton Transfer Reaction‐Quadruple Time‐of‐Flight Mass Spectrometer. These widespread long‐lasting feature high levels acetonitrile, oxygenated‐aromatics, naphthalene, are independent characteristic from open field but relate miscellaneous fuels such as combustible wastes. The positive matrix factorization approach was applied quantitatively appoint sources understand OH reactivity ( L ) secondary aerosols formation potential (SOAP) atmosphere China. We find that accounts for 24.0% ± 6.4% all NMOG mixing ratios, compared 40.1% 7.7% urban emissions. contribution these two total calculated (23.2% 6.2% 26.4% 5.1% urban) SOAP (22.0% 7.5% 23.2% 6.7% comparable normal days. In addition, biogenic sporadic also NMOGs YRD region harvest season. This study highlights critical importance China, which unaccounted past pollution regulations.

Язык: Английский

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Secondary aerosol formation during the dark oxidation of residential biomass burning emissions

Environmental Science Atmospheres, Год журнала: 2022, Номер 2(5), С. 1221 - 1236

Опубликована: Янв. 1, 2022

Particulate matter from biomass burning emissions affects air quality, ecosystems and climate; however, quantifying these effects requires that the connection between primary secondary aerosol production is firmly established. We performed atmospheric simulation chamber experiments on chemical oxidation of residential under dark conditions. Biomass organic was found to age conditions, with its oxygen-to-carbon ratio increasing by 7-34% producing 1-38 μg m-3 (5-80% increase over fresh aerosol) after 30 min exposure NO3 radicals in (corresponding 1-3 h typical nighttime radical concentrations an urban environment). The average mass concentration SOA formed dark-oxidation conditions comparable 3 (equivalent 7-10 ambient exposure) ultraviolet lights (6 or a 47% emitted concentration). dark-aging showed substantial nitrate (0.12-3.8 m-3), 46-100% which form nitrates. pH remained practically constant at 2.8 throughout experiment. This value promotes inorganic partitioning particulate phase, potentially contributing buildup boundary layer enhancing long-range transport. These results suggest through reactions additional formation pathway emission plumes should be accounted for chemical-transport models.

Язык: Английский

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Photochemical transformation of residential wood combustion emissions: dependence of organic aerosol composition on OH exposure

Atmospheric chemistry and physics, Год журнала: 2020, Номер 20(11), С. 6357 - 6378

Опубликована: Июнь 3, 2020

Abstract. Residential wood combustion (RWC) emits large amounts of gaseous and particulate organic aerosol (OA). In the atmosphere, emission is transformed via oxidative reactions, which are under daylight conditions driven mainly by hydroxyl radicals (OH). This continuing ageing produces secondary OA may change health- climate-related properties emission. However, it not well known how composition RWC-originated changes as function OH exposure. this work, emissions from two modern residential logwood appliances were photochemically aged in an oxidation flow reactor (OFR) with various exposure levels, reaching up to 6×1011 s cm−3 (equivalent 1 week atmosphere). Gaseous compounds analysed proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS), while was online a high-resolution soot particle spectrometer (SP-HR-ToF-AMS) offline situ derivatization thermal desorption–gas chromatography–time-of-flight (IDTD-GC-ToF-MS). Photochemical reactions increased carbon factor 1.3–3.9. The increase took place during first atmospheric equivalent day ageing, after enhancement independent extent photochemical state linearly throughout assessed range, ΔH:C/ΔO:C slopes between −0.17 −0.49 van Krevelen space. Ageing led acidic fragmentation products both phases, measured IDTD-GC-ToF-MS for PTR-ToF-MS phase. For compounds, formation small carbonylic combined rapid degradation primary volatile such aromatic continuous O : C H ratios. Overall, share polycyclic (PACs) particles degraded rapidly although some oxygen-substituted PACs, most notably naphthaldehydic acid, increased, particular relatively short exposures. Similarly, concentrations nitrophenols rose extensively day. During dominant transformation mechanisms shifted initial gas-phase functionalization/condensation further fragmentation. observed broad range exposures indicates that entire lifetime needs be explored fully assess potential climate health effects RWC emissions.

Язык: Английский

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Development and Evaluation of a Detailed Mechanism for Gas-Phase Atmospheric Reactions of Furans

ACS Earth and Space Chemistry, Год журнала: 2020, Номер 4(8), С. 1254 - 1268

Опубликована: Июнь 24, 2020

Furan and its alkyl derivatives (furans) are emitted to the atmosphere from multiple sources can exist in sufficient quantities affect atmospheric oxidant levels secondary pollutant formation. Such compounds their chemical transformations generally oversimplified gas-phase mechanisms used for air quality predictions modeling studies. Furans typically lumped as reactive aromatics, which largely underpredicts oxidation rates. This work presents a detailed mechanism furans major products. The reactions rate constants were derived using published data Statewide Air Pollution Research Center (SAPRC) generation system (MechGen). was implemented SAPRC-18 base enable evaluation against environmental chamber experiments. A reduced version of developed that maintains consistency compatibility with SAPRC-07/-11 mechanisms. Relative SAPRC-11 mechanism, model skill improved predicting consumption (21 26 experiments) Δ([O3] – [NO]). For latter, mean bias ±10% 13 experiments (4 SAPRC-11) >±20% only 3 (11 SAPRC-11). Sensitivity simulations performed evaluate relative importance hydroxyl radical (OH)-, nitrate (NO3)-, ozone (O3)-initiated photo-oxidation. While OH-initiated sink furans, NO3 O3 become non-negligible or even equal under dark high conditions, such may be expected during biomass burning events. no tuning fit experimental facilitate broad application modeling.

Язык: Английский

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