Ozone chemistry in western U.S. wildfire plumes

Science Advances, Journal Year: 2021, Volume and Issue: 7(50)

Published: Dec. 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.

Language: 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, Journal Year: 2021, Volume and Issue: 118(52)

Published: Dec. 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.

Language: Английский

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Emissions of Trace Organic Gases From Western U.S. Wildfires Based on WE‐CAN Aircraft Measurements

Journal of Geophysical Research Atmospheres, Journal Year: 2021, Volume and Issue: 126(11)

Published: May 9, 2021

Abstract We present emission measurements of volatile organic compounds (VOCs) for western U.S. wildland fires made on the NSF/NCAR C‐130 research aircraft during Western Wildfire Experiment Cloud Chemistry, Aerosol Absorption, and Nitrogen (WE‐CAN) field campaign in summer 2018. VOCs were measured with complementary instruments onboard C‐130, including a proton‐transfer‐reaction time‐of‐flight mass spectrometer (PTR‐ToF‐MS) two gas chromatography (GC)‐based methods. Agreement within combined instrument uncertainties (<60%) was observed most co‐measured VOCs. GC‐based speciated isomeric contributions to selected PTR‐ToF‐MS ion masses generally showed little fire‐to‐fire variation. report ratios (ERs) factors (EFs) 161 31 near‐fire smoke plume transects 24 specific individual sampled afternoon when burning conditions are typically active. Modified combustion efficiency (MCE) ranged from 0.85 0.94. The campaign‐average total VOC EF 26.1 ± 6.9 g kg −1 , approximately 67% which is accounted by oxygenated 10 abundantly emitted species contributed more than half mass. found that MCE alone explained nearly 70% variance emissions ( r 2 = 0.67) >50% 57 EFs representing carbon Finally, we variability fraction emissions, suggesting single speciation profile can describe wildfires coniferous ecosystems WE‐CAN.

Language: Английский

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Daily Local-Level Estimates of Ambient Wildfire Smoke PM_2.5 for the Contiguous US

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(19), P. 13607 - 13621

Published: Sept. 22, 2022

Smoke from wildfires is a growing health risk across the US. Understanding spatial and temporal patterns of such exposure its population impacts requires separating smoke-driven pollutants non-smoke long time series to quantify measure impacts. We develop parsimonious accurate machine learning model daily wildfire-driven PM2.5 concentrations using combination ground, satellite, reanalysis data sources that are easy update. apply our contiguous US 2006 2020, generating estimates smoke over 10 km-by-10 km grid use these characterize levels trends in PM2.5. contributions have increased by up 5 μg/m3 Western last decade, reversing decades policy-driven improvements overall air quality, with fastest for higher income populations predominantly Hispanic populations. The number people locations at least 1 day above 100 per year has 27-fold including nearly 25 million 2020 alone. Our set can bolster efforts comprehensively understand drivers societal extremes wildfire smoke.

Language: 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, Journal Year: 2023, Volume and Issue: 880, P. 163232 - 163232

Published: April 4, 2023

Language: 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, 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

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Variability and Time of Day Dependence of Ozone Photochemistry in Western Wildfire Plumes

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(15), P. 10280 - 10290

Published: July 13, 2021

Understanding the efficiency and variability of photochemical ozone (O3) production from western wildfire plumes is important to accurately estimate their influence on North American air quality. A set measurements were made NOAA Twin Otter research aircraft as a part Fire Influence Regional Global Environments Air Quality (FIREX-AQ) experiment. We use zero-dimensional (0-D) box model investigate chemistry driving O3 in modeled plumes. Modeled afternoon reached maximum mixing ratio 140 ± 50 ppbv (average standard deviation) within 20 10 min emission compared 76 12 60 30 evening Afternoon isopleths indicate that near peak NOx efficiency. radical budget describes volatile - organic compound (VOC) sensitivities these displayed rapid transition VOC-sensitive NOx-sensitive chemistry, driven by HOx (=OH + HO2) photolysis nitrous acid (HONO) (48 20% primary HOx) formaldehyde (HCHO) (26 9%) emitted directly fire. Evening exhibit slower caused reduction rates fire emissions. controlled HONO (53 7%), HCHO (18 9%), alkene ozonolysis (17 9%).

Language: Английский

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Direct estimates of biomass burning NO&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; emissions and lifetimes using daily observations from TROPOMI

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(20), P. 15569 - 15587

Published: Oct. 18, 2021

Abstract. Biomass burning emits an estimated 25 % of global annual nitrogen oxides (NOx), important constituent that participates in the oxidative chemistry atmosphere. Estimates NOx emission factors, representing amount per mass burned, are primarily based on field or laboratory case studies, but sporadic and transient nature wildfires makes it challenging to verify whether these studies represent behavior fires occur earth. Satellite remote sensing provides a unique view earth, allowing for study emissions downwind evolution from large number fires. We describe direct estimates lifetimes using exponentially modified Gaussian analysis daily TROPOspheric Monitoring Instrument (TROPOMI) retrievals NO2 tropospheric columns. update priori profile with fine-resolution (0.25∘) model simulation NASA's GEOS Composition Forecasting System (GEOS-CF), which largely enhances columns over fire plumes. derive representative factors six fuel types globally by linking TROPOMI-derived observations radiative power Moderate Resolution Imaging Spectroradiometer (MODIS). Satellite-derived consistent those derived situ measurements. observe decreasing lifetime emissions, we infer is due increase both abundance hydroxyl radical production. Our findings suggest promise applying space-based track chemical reactive wildfires.

Language: Английский

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Quantifying urban, industrial, and background changes in NO&lt;sub&gt;2&lt;/sub&gt; during the COVID-19 lockdown period based on TROPOMI satellite observations

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(6), P. 4201 - 4236

Published: March 31, 2022

Abstract. The COVID-19 lockdown had a large impact on anthropogenic emissions of air pollutants and particularly nitrogen dioxide (NO2). While the overall NO2 decline over some cities is well-established, understanding details remains challenge since multiple source categories contribute. In this study, new method isolation three components (background NO2, from urban sources, industrial point sources) applied to estimate each them. approach based fitting satellite data by statistical model with empirical plume dispersion functions driven meteorological reanalysis. Population density surface elevation as well coordinates sources were used in analysis. tropospheric vertical column (VCD) values measured Tropospheric Monitoring Instrument (TROPOMI) board Sentinel-5 Precursor 261 areas for period 16 March 15 June 2020 compared average VCD same 2018 2019. background component remained almost unchanged, declined −18 % −28 most regions. India, South America, part Europe (particularly, Italy, France, Spain) demonstrated −40 −50 emission decline. contrast, China, where was during analysed period, was, average, only -4.4±8 %. Emissions varied greatly region -4.8±6 China -40±10 India. Estimated changes are correlated Google mobility (the correlation coefficient 0.62) confirming that traffic one key elements emissions. No found between data. On global scale, remarkably stable 2018, 2019, 2021, averages all being within ±2.5 suggesting there no substantial drifts or shifts TROPOMI clearly an outlier: 2020, mean (without China) -6.0%±1.2 -26.7±2.6 20σ below baseline level other years.

Language: 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, Journal Year: 2023, Volume and Issue: 57(39), P. 14648 - 14660

Published: Sept. 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.

Language: Английский

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