How emissions uncertainty influences the distribution and radiative impacts of smoke from fires in North America

Atmospheric chemistry and physics, Journal Year: 2020, Volume and Issue: 20(4), P. 2073 - 2097

Published: Feb. 26, 2020

Abstract. Fires and the aerosols that they emit impact air quality, health, climate, but abundance properties of carbonaceous aerosol (both black carbon organic carbon) from biomass burning (BB) remain uncertain poorly constrained. We aim to explore uncertainties associated with fire emissions their quality radiative impacts underlying dry matter consumed factors. To investigate this, we compare model simulations a global chemical transport model, GEOS-Chem, driven by variety emission inventories surface airborne observations (BC) (OA) concentrations satellite-derived optical depth (AOD). focus on two fire-detection-based and/or burned-area-based (FD-BA) using burned area active counts, respectively, i.e., Global Fire Emissions Database version 4 (GFED4s) small fires INventory NCAR 1.5 (FINN1.5), power (FRP)-based approaches, Quick Emission Dataset 2.4 (QFED2.4) Assimilation System 1.2 (GFAS1.2). show that, across inventories, BB (BBA) differ factor 7 over North America differences, not factors, drive this spread. find QFED2.4 generally overestimate BC and, lesser extent, OA fire-influenced aircraft campaigns in (ARCTAS DC3) Interagency Monitoring Protected Visual Environments (IMPROVE) network, while FINN1.5 substantially underestimate concentrations. The GFED4s GFAS1.2-driven provide best agreement mass at (IMPROVE), observed aloft (DC3 ARCTAS), AOD MODIS America. also sensitivity simulation including an enhanced source secondary (SOA) fires, based NOAA Lab 2016 experiments, produces substantial additional OA; however, spread primary estimates implies magnitude SOA can be neither confirmed nor ruled out when comparing against explored here. Given uncertainty emissions, as represented these four sizeable range 2012 annual BBA PM2.5 population-weighted exposure Canada contiguous US (0.5 1.6 µg m−3). estimated direct effect (−0.11 −0.048 W m−2) is large comparable forcing (−0.09 Fifth Assessment Report (AR5) Intergovernmental Panel Climate Change (IPCC). Our analysis suggests challenges our ability accurately characterize smoke climate.

Language: Английский

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Secondary organic aerosol formation from the laboratory oxidation of biomass burning emissions

Atmospheric chemistry and physics, Journal Year: 2019, Volume and Issue: 19(19), P. 12797 - 12809

Published: Oct. 14, 2019

Abstract. Biomass burning is an important source of aerosol and trace gases to the atmosphere, but how these emissions change chemically during their lifetimes not fully understood. As part Fire Influence on Regional Global Environments Experiment (FIREX 2016), we investigated effect photochemical aging biomass organic (BBOA) with a focus fuels from western United States. Emissions were sampled into small (150 L) environmental chamber photochemically aged via addition ozone irradiation by 254 nm light. While some fraction species undergoes photolysis, vast majority occurs reaction OH radicals, total exposures corresponding equivalent up 10 d atmospheric oxidation. For all burned, large rapid changes are seen in ensemble chemical composition BBOA, as measured mass spectrometer (AMS). Secondary (SOA) formation for experiments continues grow increasing exposure, magnitude SOA highly variable between experiments. This variability can be explained well combination differences exposure concentration non-methane (NMOGs) before oxidation, PTR-ToF-MS (r2 values 0.64 0.83). From this relationship, calculate carbon NMOGs that converted function time, yields ranging 24±4 % after 6 h 56±9 4 d.

Language: Английский

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Characterization of organic aerosol across the global remote troposphere: a comparison of ATom measurements and global chemistry models

Atmospheric chemistry and physics, Journal Year: 2020, Volume and Issue: 20(8), P. 4607 - 4635

Published: April 21, 2020

Abstract. The spatial distribution and properties of submicron organic aerosol (OA) are among the key sources uncertainty in our understanding effects on climate. Uncertainties particularly large over remote regions free troposphere Southern Ocean, where very few data have been available OA predictions from AeroCom Phase II global models span 2 to 3 orders magnitude, greatly exceeding model spread source regions. (nearly) pole-to-pole vertical non-refractory aerosols was measured with an mass spectrometer onboard NASA DC-8 aircraft as part Atmospheric Tomography (ATom) mission during Northern Hemisphere summer (August 2016) winter (February 2017). This study presents first extensive characterization concentrations their level oxidation atmosphere. sulfate major contributors by troposphere, together sea salt marine boundary layer. Sulfate dominant lower stratosphere. a strong seasonal zonal variability, highest levels influenced biomass burning Africa (up 10 µg sm−3). Lower (∼0.1–0.3 sm−3) observed northern middle high latitudes low (<0.1 southern latitudes. ATom dataset is used evaluate eight current chemistry that implement variety commonly representations chemistry, well AeroCom-II ensemble. ensemble captures average concentrations, individual remains within factor 5. These results significantly improved ensemble, which shows overestimations these However, some agreement observations occurs for wrong reasons, tendency overestimate primary fraction underestimate secondary fraction. Measured highly oxygenated, carbon (OA ∕ OC) ratios ∼2.2–2.8, 30 %–60 % more oxygenated than models, can lead significant errors concentrations. model–measurement comparisons presented here support concept dynamic system proposed Hodzic et al. (2016), enhanced removal stronger production needed provide better observations.

Language: Английский

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Rapid evolution of aerosol particles and their optical properties downwind of wildfires in the western US

Atmospheric chemistry and physics, Journal Year: 2020, Volume and Issue: 20(21), P. 13319 - 13341

Published: Nov. 11, 2020

Abstract. During the first phase of Biomass Burn Operational Project (BBOP) field campaign, conducted in Pacific Northwest, DOE G-1 aircraft was used to follow time evolution wildfire smoke from near point emission locations 2–3.5 h downwind. In nine flights we made repeated transects plumes at varying downwind distances and could thereby plume's evolution. On average there little change dilution-normalized aerosol mass concentration as a function distance. This consistency hides dynamic system which primary particles are evaporating secondary ones condensing. Organic is oxidized result. all more than 90 % organic. freshly emitted aerosol, NH4+ approximately equivalent NO3. After 2 daytime aging, increased sum Cl, SO42, Particle size with distance, causing be efficient scatters. Averaged over flights, scattering efficiency (MSE) ∼ by 56 doubled one flight. Mechanisms for redistributing small large discussed. Coagulation effective moving Aitken accumulation modes but yields only minor increase MSE. As absorption remained nearly constant age, single scatter albedo controlled age-dependent scattering. Near-fire had (SSA) 0.8–0.9. 1 aging SSAs were typically 0.9 greater. Assuming global-average surface atmospheric conditions, observed age dependence SSA would direct radiative effect plume zero fire cooling

Language: Английский

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Vertical variability of the properties of highly aged biomass burning aerosol transported over the southeast Atlantic during CLARIFY-2017

Atmospheric chemistry and physics, Journal Year: 2020, Volume and Issue: 20(21), P. 12697 - 12719

Published: Nov. 3, 2020

Abstract. Seasonal biomass burning (BB) from June to October in central and southern Africa leads absorbing aerosols being transported over the South Atlantic Ocean every year contributes significantly regional climate forcing. The vertical distribution of submicron their properties were characterized remote southeast Atlantic, using airborne situ measurements made during CLoud-Aerosol-Radiation Interactions Forcing for Year 2017 (CLARIFY-2017) campaign. BB emitted flaming-controlled fires intensively observed region surrounding Ascension Island, marine boundary layer (MBL) free troposphere (FT) up 5 km. We show that had undergone a significant ageing process > 7 d transit source, as indicated by highly oxidized organic aerosol. aged far-field CLARIFY also especially rich black carbon (BC), with relatively low single-scattering albedos (SSAs), compared those other regions. column-weighted dry SSAs be 0.85, 0.84 0.83 at 405, 550 658 nm respectively. found variation SSA, function relative chemical composition size. lowest SSA column was generally FT around 2000 m altitude (averages: 0.82, 0.81 0.79 nm). This finding is important since it means across are more than currently represented models, implying radiative forcing may strongly positive previously thought. Furthermore, FT, average increased 0.87, 0.86 0.85 associated an enhanced inorganic nitrate mass fraction aerosol size, likely resulting partitioning ammonium existing particles higher lower temperature humidity. After entrainment into (BL), smaller size larger scattering material resultant mostly due emissions removal drizzle. In BL, decreased surface BL top, highest near surface. Our results provide unique observational constraints on parameterizations used modelling radiation interactions this region. recommend future work should consider impact variability models.

Language: Английский

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Biomass-burning-derived particles from a wide variety of fuels – Part 2: Effects of photochemical aging on particle optical and chemical properties

Atmospheric chemistry and physics, Journal Year: 2020, Volume and Issue: 20(14), P. 8511 - 8532

Published: July 22, 2020

Abstract. Particles in smoke emitted from biomass combustion have a large impact on global climate and urban air quality. There is limited understanding of how particle optical properties – especially the contributions black carbon (BC) brown (BrC) evolve with photochemical aging smoke. We analyze evolution chemical composition particles produced wide variety fuels, largely western United States. The photochemically aged reaction chamber over atmospheric-equivalent timescales ranging 0.25 to 8 d. Various aerosol (e.g., single-scatter albedo, wavelength dependence absorption, BC mass absorption coefficient, MACBC) evolved aging, specific dependent initial conditions. coatings (the so-called lensing effect) was small, even after aging. BrC absorptivity (MACBrC) varied between individual burns but decreased consistently at longer times; generally increased observed changes result combination secondary organic (SOA) production heterogeneous oxidation primary OA mass, SOA being major driver changes. time, reflecting both formation precursors having range lifetimes respect OH evolving environment within chamber. Although decreases dilution-corrected may actually increase SOA. These experimental results provide context for interpretation ambient observations biomass-combustion-derived plumes.

Language: Английский

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Atmospheric aging enhances the ice nucleation ability of biomass-burning aerosol

Science Advances, Journal Year: 2021, Volume and Issue: 7(9)

Published: Feb. 24, 2021

Ability of biomass-burning smoke particles to glaciate clouds increases as the plume undergoes atmospheric dilution and aging.

Language: Английский

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Rate of atmospheric brown carbon whitening governed by environmental conditions

Proceedings of the National Academy of Sciences, Journal Year: 2022, Volume and Issue: 119(38)

Published: Sept. 12, 2022

Biomass burning organic aerosol (BBOA) in the atmosphere contains many compounds that absorb solar radiation, called brown carbon (BrC). While BBOA is atmosphere, BrC can undergo reactions with oxidants such as ozone which decrease absorbance, or whiten. The effect of temperature and relative humidity (RH) on whitening has not been well constrained, leading to uncertainties when predicting direct radiative climate. Using an flow-tube reactor, we show by oxidation strongly dependent RH temperature. a poke-flow technique, viscosity also depends these conditions. measured rate described data, assuming due occurring bulk BBOA, within thin shell beneath surface. our combined datasets, developed kinetic model this process, lifetime 1 d less below ∼1 km altitude but often much longer than above altitude. Including dependence chemical transport causes large change predicted warming Overall, results illustrate need be considered understand role atmosphere.

Language: Английский

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Modeled and observed properties related to the direct aerosol radiative effect of biomass burning aerosol over the southeastern Atlantic

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(1), P. 1 - 46

Published: Jan. 3, 2022

Abstract. Biomass burning smoke is advected over the southeastern Atlantic Ocean between July and October of each year. This plume overlies mixes into a region persistent low marine clouds. Model calculations climate forcing by this vary significantly in both magnitude sign. NASA EVS-2 (Earth Venture Suborbital-2) ORACLES (ObseRvations Aerosols above CLouds their intEractionS) had deployments for field campaigns off west coast Africa 3 consecutive years (September 2016, August 2017, 2018) with goal better characterizing as function monthly evolution measuring parameters necessary to calculate direct aerosol radiative effect. Here, dataset satellite retrievals cloud properties are used test representation underlying layer two regional models (WRF-CAM5 CNRM-ALADIN) global (GEOS UM-UKCA). The focus on comparisons those that primary determinants effect vertical distribution its properties. representativeness observations averages tested campaign, sampled mean light extinction generally found be within 20 % at altitudes. When compared observations, all models, simulated too vertically diffuse has smaller gradients, UM-UKCA), core displaced lower than observations. Plume carbon monoxide, black carbon, organic masses indicate underestimates modeled concentrations, leading, general, mid-visible optical depth. Biases single scatter albedo positive negative across models. Observed gradients not captured but do capture coarse temporal evolution, correctly simulating higher values (2018) (2017) September (2016). Uncertainties measured absorption Ångstrom exponent were large propagate negligible (<4 %) uncertainty integrated solar and, therefore, biases fraction, scene below plume, four thickness clouds is, average, well WRF-CAM5 ALADIN stratocumulus underestimated GEOS model; UM-UKCA simulates high. Overall, study demonstrates utility repeated, semi-random sampling multiple can give insights model how these affect forcing. combined impact (DARE) estimated using first-order approximation subset five comparison grid boxes. A significant finding observed box average yield (warming) boxes, whereas DARE grid-box-averaged ranges from much larger small, values. It shown quantitatively offset other, so improvements reduce only one property (e.g., fraction) would lead even greater DARE. Across fraction depth contribute largest DARE, also making contribution.

Language: Английский

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Sulfate Formation in Incense Burning Particles: A Single-Particle Mass Spectrometric Study

Environmental Science & Technology Letters, Journal Year: 2022, Volume and Issue: 9(9), P. 718 - 725

Published: Aug. 26, 2022

Incense burning is a common ritual in Asian communities, and it emits massive amounts of particles. These particles can undergo atmospheric aging upon exposure to sunlight other pollutants. In this work, we observed sulfate formation fresh incense SO2, using single-particle aerosol mass spectrometer (SPAMS). Analysis the positive spectra classified as K-type OC-type. both dark light experiments, SO2 uptake oxidation were found preferentially OC-type over Sulfate formation, represented by number fraction sulfate-containing (FS), under was likely due gaseous oxidants. FS increased with UV, mainly attributable photosensitization reactions. While more formed at higher relative humidity (RH) dark, independent RH. The increase photochemistry effective lower RH, where photoactive compounds concentrated generated photo-oxidants. This effect outweighed that reduced dissolution. Since contain organic photosensitizers have also been biomass particles, our findings could shed on potential trigger formation.

Language: Английский

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