Ozone chemistry in western U.S. wildfire plumes

Science Advances, Год журнала: 2021, Номер 7(50)

Опубликована: Дек. 8, 2021

Wildfires are a substantial but poorly quantified source of tropospheric ozone (O3). Here, to investigate the highly variable O3 chemistry in wildfire plumes, we exploit situ chemical characterization western wildfires during FIREX-AQ flight campaign and show that production can be predicted as function experimentally constrained OH exposure, volatile organic compound (VOC) reactivity, fate peroxy radicals. The exhibits rapid transition regimes. Within few daylight hours, formation substantially slows is largely limited by abundance nitrogen oxides (NOx). This finding supports previous observations enhanced when VOC-rich smoke mixes into NOx-rich urban thereby deteriorating air quality. Last, relate underlying fire characteristics, enabling more accurate representation atmospheric models used study quality predict climate.

Язык: Английский

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Large contribution of biomass burning emissions to ozone throughout the global remote troposphere

Proceedings of the National Academy of Sciences, Год журнала: 2021, Номер 118(52)

Опубликована: Дек. 20, 2021

Significance Understanding the sources of tropospheric ozone is important for effective air quality management and accurate radiative forcing attribution. Biomass burning emits large quantities precursors to lower atmosphere. This source can drive regional-scale production, but its impact on global poorly constrained. Here, we present unique in situ aircraft observations continental pollution tracers. Ozone enhancements attributable biomass equal or exceed those from urban emissions, a result that not predicted by current chemical transport models. These findings represent potentially major shift understanding atmosphere indicate need model developments improve representation ozone.

Язык: Английский

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Fire Influence on Regional to Global Environments and Air Quality (FIREX‐AQ)

Journal of Geophysical Research Atmospheres, Год журнала: 2022, Номер 128(2)

Опубликована: Дек. 30, 2022

Abstract The NOAA/NASA Fire Influence on Regional to Global Environments and Air Quality (FIREX‐AQ) experiment was a multi‐agency, inter‐disciplinary research effort to: (a) obtain detailed measurements of trace gas aerosol emissions from wildfires prescribed fires using aircraft, satellites ground‐based instruments, (b) make extensive suborbital remote sensing fire dynamics, (c) assess local, regional, global modeling fires, (d) strengthen connections observables the ground such as fuels fuel consumption satellite products burned area radiative power. From Boise, ID western were studied with NASA DC‐8 two NOAA Twin Otter aircraft. high‐altitude ER‐2 deployed Palmdale, CA observe some these in conjunction overpasses other Further conducted three mobile laboratories sites, 17 different forecast analyses for fire, air quality climate implications. Salina, KS investigated 87 smaller Southeast in‐situ data collection. Sampling by all platforms designed measure gases aerosols multiple transects capture chemical transformation perform observations smoke plumes under day night conditions. linked consumed power orbital collected during overflights sampling fuels.

Язык: Английский

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Parameterizations of US wildfire and prescribed fire emission ratios and emission factors based on FIREX-AQ aircraft measurements

Atmospheric chemistry and physics, Год журнала: 2024, Номер 24(2), С. 929 - 956

Опубликована: Янв. 23, 2024

Abstract. Extensive airborne measurements of non-methane organic gases (NMOGs), methane, nitrogen oxides, reduced species, and aerosol emissions from US wild prescribed fires were conducted during the 2019 NOAA/NASA Fire Influence on Regional to Global Environments Air Quality campaign (FIREX-AQ). Here, we report atmospheric enhancement ratios (ERs) inferred emission factors (EFs) for compounds measured board NASA DC-8 research aircraft nine wildfires one fire, which encompass a range vegetation types. We use photochemical proxies identify young smoke reduce effects chemical degradation our calculations. ERs EFs calculated FIREX-AQ observations agree within factor 2, with values reported previous laboratory field studies more than 80 % carbon- nitrogen-containing species. Wildfire are parameterized based correlations sum NMOGs reactive oxides (NOy) modified combustion efficiency (MCE) as well other signatures indicative flaming/smoldering combustion, including carbon monoxide (CO), dioxide (NO2), black aerosol. The primary NMOG correlates MCE an R2 0.68 slope −296 ± 51 g kg−1, consistent studies. mixing CO 0.98 137 4 ppbv per parts million by volume (ppmv) CO, demonstrating that can be estimated CO. Individual species correlate better NO2, NOy, More half NOy in fresh plumes is NO2 0.95 ratio 0.55 0.05 ppbv−1, highlighting fast photochemistry had already occurred sampled fire plumes. follows trends observed experiments increases exponentially MCE, due increased key at higher flaming combustion. These parameterizations will provide accurate boundary conditions modeling satellite plume chemistry evolution predict downwind formation secondary pollutants, ozone

Язык: Английский

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Nighttime and daytime dark oxidation chemistry in wildfire plumes: an observation and model analysis of FIREX-AQ aircraft data

Atmospheric chemistry and physics, Год журнала: 2021, Номер 21(21), С. 16293 - 16317

Опубликована: Ноя. 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.

Язык: Английский

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Complexity in the Evolution, Composition, and Spectroscopy of Brown Carbon in Aircraft Measurements of Wildfire Plumes

Geophysical Research Letters, Год журнала: 2022, Номер 49(9)

Опубликована: Апрель 12, 2022

Abstract Biomass burning is a major source of light‐absorbing organic aerosol (brown carbon), but its composition, chemical evolution, and lifetime are not well known. We measured water‐soluble brown carbon absorption from 310 to 500 nm on the National Oceanic Atmospheric Administration Twin Otter aircraft during flights downwind western United States wildfires in summer 2019. The sampling strategy was near‐Lagrangian plume ages spanned 0–5 hr. Trends mass coefficient with age varied between flights, did show an exponential decay over these short time scales. spectra were smoothly varying, without identifiable contributions individual chromophores structured absorption. Using tracer ions reference spectra, calculated contribution 4‐nitrocatechol total <22 ± 9% <11 5%, although spectral fitting showed that it may be as low <1.1% <0.6% at 365 405 nm, respectively.

Язык: Английский

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A newly developed Lagrangian chemical transport scheme: Part 1. Simulation of a boreal forest fire plume

The Science of The Total Environment, Год журнала: 2023, Номер 880, С. 163232 - 163232

Опубликована: Апрель 4, 2023

Язык: Английский

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Influence of Wildfire on Urban Ozone: An Observationally Constrained Box Modeling Study at a Site in the Colorado Front Range

Environmental Science & Technology, Год журнала: 2023, Номер 57(3), С. 1257 - 1267

Опубликована: Янв. 6, 2023

Increasing trends in biomass burning emissions significantly impact air quality North America. Enhanced mixing ratios of ozone (O3) urban areas during smoke-impacted periods occur through transport O3 produced within the smoke or pyrogenic volatile organic compounds (PVOCs) with nitrogen oxides (NOx = NO + NO2) to enhance local production. Here, we analyze a set detailed chemical measurements, including carbon monoxide (CO), NOx, and speciated (VOCs), evaluate effects transported from relatively long-range fires on measured at site Boulder, Colorado, summer 2020. Relative smoke-free period, CO, background O3, OH reactivity, total VOCs increased both periods, but NOx remained approximately constant. These observations are consistent PVOCs (comprised primarily oxygenates) not influence upwind area. Box-model calculations show that production all three was NOx-sensitive regime. Consequently, this locally similar insensitive increase PVOCs. However, calculated sensitivities substantially transition NOx-saturated (VOC-sensitive) regimes. results suggest (1) is main driver for increases (2) may cause an additional areas. Additional VOC measurements impacted necessary broadly quantify wildfire develop effective mitigation strategies.

Язык: Английский

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Space-Based Observations of Ozone Precursors within California Wildfire Plumes and the Impacts on Ozone-NO_x-VOC Chemistry

Environmental Science & Technology, Год журнала: 2023, Номер 57(39), С. 14648 - 14660

Опубликована: Сен. 13, 2023

The frequency of wildfires in the western United States has escalated recent decades. Here we examine impacts on ground-level ozone (O3) precursors and O3-NOx-VOC chemistry from source to downwind urban areas. We use satellite retrievals nitrogen dioxide (NO2) formaldehyde (HCHO, an indicator VOC) Tropospheric Monitoring Instrument (TROPOMI) track evolution O3 over California 2018 2020. improved these by updating a priori profiles explicitly accounting for effects smoke aerosols. TROPOMI observations reveal that extensive intense fire 2020 led overall increase statewide annual average HCHO NO2 columns 16% 9%. level offsets anthropogenic NOx emission reduction COVID-19 lockdown. enhancement within plumes is concentrated near regions actively burning, whereas far-reaching, extending areas due secondary production longer-lived VOCs such as ethene. Consequently, larger occurs NOx-limited regions, while greater VOC-limited areas, both contributing more efficient production.

Язык: Английский

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Urban ozone formation and sensitivities to volatile chemical products, cooking emissions, and NO_x upwind of and within two Los Angeles Basin cities

Atmospheric chemistry and physics, Год журнала: 2025, Номер 25(2), С. 1121 - 1143

Опубликована: Янв. 28, 2025

Abstract. Volatile chemical products (VCPs) and other non-traditional anthropogenic sources, such as cooking, contribute substantially to the volatile organic compound (VOC) budget in urban areas, but their impact on ozone formation is less certain. This study employs Lagrangian box modeling sensitivity analyses evaluate response sector-specific VOC nitrogen oxide (NOx) emissions two Los Angeles (LA) Basin cities during summer of 2021. The model simulated photochemical processing transport temporally spatially gridded from FIVE-VCP-NEI17NRT inventory accurately simulates variability magnitude O3, NOx, speciated VOCs Pasadena, CA. show that (AVOC) enhance mean daily maximum 8 h average Pasadena by 13 ppb, whereas biogenic (BVOCs) 9.4 ppb. Of influenced AVOCs, VCPs represent largest fraction at 45 %, while cooking fossil fuel are comparable 26 % 29 respectively. NOx along trajectory paths indicate regime varies temporally. modeled primarily NOx-saturated across dense core peak production Pasadena. Lowering 25 moves NOx-limited chemistry afternoon hours shrinks spatial extent saturation towards downtown LA. Further using represented a separate state requires steeper reductions transition sensitivity, further suggesting representing reactivity inventories critical determining effectiveness future reduction policies.

Язык: Английский

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