Shortwave absorption by wildfire smoke dominated by dark brown carbon

Nature Geoscience, Journal Year: 2023, Volume and Issue: 16(8), P. 683 - 688

Published: Aug. 1, 2023

Wildfires emit large amounts of black carbon and light-absorbing organic carbon, known as brown into the atmosphere. These particles perturb Earth's radiation budget through absorption incoming shortwave radiation. It is generally thought that loses its absorptivity after emission in atmosphere due to sunlight-driven photochemical bleaching. Consequently, atmospheric warming effect exerted by remains highly variable poorly represented climate models compared with relatively nonreactive carbon. Given wildfires are predicted increase globally coming decades, it increasingly important quantify these radiative impacts. Here we present measurements ensemble-scale particle-scale smoke plumes from western United States. We find a type dark contributes three-quarters short visible light half long absorption. This strongly absorbing aerosol species water insoluble, resists daytime photobleaching increases night-time processing. Our findings suggest parameterizations need be revised improve estimation forcing associated warming.

Language: Английский

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Identifying and correcting interferences to PTR-ToF-MS measurements of isoprene and other urban volatile organic compounds

Atmospheric measurement techniques, Journal Year: 2024, Volume and Issue: 17(2), P. 801 - 825

Published: Jan. 31, 2024

Abstract. Proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) is a technique commonly used to measure ambient volatile organic compounds (VOCs) in urban, rural, and remote environments. PTR-ToF-MS known produce artifacts from ion fragmentation, which complicates the interpretation quantification of key atmospheric VOCs. This study evaluates extent fragmentation other ionization processes impact urban measurements ions typically assigned isoprene (m/z 69, C5H8H+), acetaldehyde 45, CH3CHO+), benzene 79, C6H6H+). Interferences are identified using gas chromatography (GC) pre-separation, these interferences quantified ground-based airborne number US cities, including Las Vegas, Los Angeles, New York City, Detroit. In regions with low biogenic emissions (e.g., Vegas), higher-carbon aldehydes cycloalkanes emitted anthropogenic sources may contribute m/z 69 by as much 50 % during day, while majority signal at attributed night. higher fraction studies, likely results differences reactivity between interfering species along subsequent changes VOC mixture altitudes. For PTR masses, 45 observed due O2+ VOCs solvents, becoming more important source areas. We present methods correct interferences, provide better agreement GC isomer-specific molecules. These observations show utility deploying pre-separation for spectra.

Language: 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, Journal Year: 2024, Volume and Issue: 24(2), P. 929 - 956

Published: Jan. 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

Language: Английский

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Impact of Biomass Burning Organic Aerosol Volatility on Smoke Concentrations Downwind of Fires

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(44), P. 17011 - 17021

Published: Oct. 24, 2023

Biomass burning particulate matter (BBPM) affects regional air quality and global climate, with impacts expected to continue grow over the coming years. We show that studies of North American fires have a systematic altitude dependence in measured BBPM normalized excess mixing ratio (NEMR; ΔPM/ΔCO), airborne high-altitude showing factor 2 higher NEMR than ground-based measurements. report direct measurements volatility partially explain difference observed across platforms. find when heated 40-45 °C an thermal denuder, 19% lofted smoke PM1 evaporates. Thermal denuder are consistent evaporation single plume was sampled range temperatures as descended from 4 km altitude. also demonstrate chemical aging differences PM emission factors can not fully platform-dependent differences. When is applied output High Resolution Rapid Refresh Smoke model, we predict lower at surface compared by aircraft. These results emphasize significant role gas-particle partitioning plays determining wildfire smoke.

Language: Английский

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Air Pollution Interactions with Weather and Climate Extremes: Current Knowledge, Gaps, and Future Directions

Current Pollution Reports, Journal Year: 2024, Volume and Issue: 10(3), P. 430 - 442

Published: Feb. 22, 2024

Language: Английский

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Emission Factors From Wildfires in the Western US: An Investigation of Burning State, Ground Versus Air, and Diurnal Dependencies During the FIREX‐AQ 2019 Campaign

Journal of Geophysical Research Atmospheres, Journal Year: 2024, Volume and Issue: 129(1)

Published: Jan. 5, 2024

Abstract Emission factors (EFs) are crucial in understanding the effects of wildfire emissions on air quality. We examined variability EFs three wildfires (Nethker, Castle, and 204 Cow) during 2019 Western US season using Aerodyne Mobile Laboratory (AML) compared them to previous studies. The AML sampling captured high degree present wildfires, we report results for a range combustion conditions that is more extensive than field laboratory For instance, from freshly started flaming fuels rare EF measurements at very modified efficiencies (MCEs); MCEs >0.9. Differences between AML‐observed were attributed burning state/MCE rather fuel type. A comparison versus MCE was made linear fits observations reveal important differences incorporate these MCEs. some species, there remains an dependence values, while others reach minimum value exhibit either no or weak above it. found many studied compounds when comparing ground‐based airborne observations, with generally greater possibly due photochemical oxidation. largest monoterpenes acetaldehyde. Comparisons aircraft values literature emission ratios, mixed agreement caused by MCE. drove diurnal differences.

Language: Английский

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Dark brown carbon from biomass burning contributes to significant global-scale positive forcing

One Earth, Journal Year: 2025, Volume and Issue: unknown, P. 101205 - 101205

Published: Feb. 1, 2025

Language: Английский

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Comparison of airborne measurements of NO, NO₂, HONO, NO_y, and CO during FIREX-AQ

Atmospheric measurement techniques, Journal Year: 2022, Volume and Issue: 15(16), P. 4901 - 4930

Published: Aug. 29, 2022

Abstract. We present a comparison of fast-response instruments installed onboard the NASA DC-8 aircraft that measured nitrogen oxides (NO and NO2), nitrous acid (HONO), total reactive odd (measured both as (NOy) from sum individually species (ΣNOy)), carbon monoxide (CO) in troposphere during 2019 Fire Influence on Regional to Global Environments Air Quality (FIREX-AQ) campaign. By targeting smoke summertime wildfires, prescribed fires, agricultural burns across continental United States, FIREX-AQ provided unique opportunity investigate measurement accuracy concentrated plumes where hundreds coexist. Here, we compare NO measurements by chemiluminescence (CL) laser-induced fluorescence (LIF); NO2 CL, LIF, cavity-enhanced spectroscopy (CES); HONO CES iodide-adduct chemical ionization mass spectrometry (CIMS); CO tunable diode laser absorption (TDLAS) integrated cavity output (ICOS). Additionally, NOy using CL instrument were compared with ΣNOy (= + nitric (HNO3) acyl peroxy nitrates (APNs) submicrometer particulate nitrate (pNO3)). Other not included they either contributed minimally it (e.g., C1–C5 alkyl nitrates, nitryl chloride (ClNO2), dinitrogen pentoxide (N2O5)) or higher oxidized (NO3), non-acyl peroxynitrates, coarse-mode aerosol nitrate). The intercomparisons demonstrate following points: (1) LIF agreed well within uncertainties but potentially reduced time response for instrument; (2) uncertainties, was average 10 % higher; (3) CIMS highly correlated each fire plume transect, correlation slope vs. all 1 Hz data 1.8, which attribute reduction sensitivity high-temperature environments; (4) budget closure demonstrated flights combined 25 %. However, used fluid dynamic flow model estimate pNO3 sampling fraction through inlet variable one flight another ranged between 0.36 0.99, meaning approximately 0 %–24 may have been unaccounted be due unmeasured such organic nitrates; (5) ICOS TDLAS systematic offset averaged 2.87 ppbv; (6) integrating followed fitting values improved independent measurements.

Language: Английский

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Health Risk Implications of Volatile Organic Compounds in Wildfire Smoke During the 2019 FIREX‐AQ Campaign and Beyond

GeoHealth, Journal Year: 2022, Volume and Issue: 6(8)

Published: June 19, 2022

Fire Influence on Regional to Global Environments and Air Quality was a NOAA/NASA collaborative campaign conducted during the summer of 2019. The objectives included identifying quantifying wildfire composition, smoke evolution, climate health impacts wildfires agricultural fires in United States. Ground based mobile sampling via sorbent tubes occurred at Nethker Williams Flats (2019) Chief Timothy Whitetail Loop (2020) Idaho Washington. samples were analyzed through thermal desorption-gas chromatography-mass spectrometry for variety volatile organic compounds elucidate both composition impacts. Benzene, toluene, ethylbenzene, xylenes, butenes, phenol, isoprene pinenes observed smoke, with benzene ranging from 0.04 25 ppbv. Health risk assessed each fire by determining sub-chronic (wildfire event) projected chronic inhalation exposure benzene, carcinogen, as well other non-carcinogenic including hexane. cancer 1 extra per million people ranged 19 cancers scenarios, compared background level people. hazard index less than one all scenarios sampled, which considered low non-cancer events.

Language: Английский

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Wildland Fires Worsened Population Exposure to PM_2.5 Pollution in the Contiguous United States

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(48), P. 19990 - 19998

Published: Nov. 9, 2023

As wildland fires become more frequent and intense, fire smoke has significantly worsened the ambient air quality, posing greater health risks. To better understand impact of wildfire on we developed a modeling system to estimate daily PM2.5 concentrations attributed both nonsmoke sources across contiguous U.S. We found that most significant quality in West Coast, followed by Southeastern Between 2007 2018, contributed over 25% at ∼40% all regulatory monitors EPA's (AQS) for than one month per year. People residing outside vicinity an EPA AQS monitor (defined 5 km radius) were subject 36% days compared with those nearby. Lowering national standard (NAAQS) annual mean between 9 10 μg/m3 would result approximately 35–49% falling nonattainment areas, taking into account smoke. If contribution is excluded, this percentage be reduced 6 9%, demonstrating negative quality.

Language: Английский

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