Emission and Evolution of Submicron Organic Aerosol in Smoke from Wildfires in the Western United States

Garofalo, Lauren A.; Pothier, Matson A.; Levin, Ezra J. T.; Campos, T.; Kreidenweis, Sonia M.; Farmer, Delphine K.

doi:10.1021/acsearthspacechem.9b00125

Cited by 126 publications

(181 citation statements)

References 59 publications

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“…The high resolution ion C2H4O2 + contributes to and exhibits similar behavior as f60; the slope for fC2H4O2+ against f60 is 0.98. While it is known that properties such as f60 vary in different biomass burning samples (Schneider et al, 2006) or between near-source intercepts of different ambient plumes (Garofalo et al, 2019), the specific dependence on burn conditions or overall particle composition (e.g.…”

Section: Oa Composition and Volatilitymentioning

confidence: 99%

Biomass-burning derived particles from a wide variety of fuels: Part 1: Properties of primary particles

McClure¹,

Lim²,

Hagan³

et al. 2019

Preprint

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Abstract. Relationships between various optical, physical, and chemical properties of biomass combustion derived particles are characterized for particles produced from a wide range of fuels and burn conditions. The modified combustion efficiency (MCE), commonly used to parameterize biomass particle emissions and properties, is shown to generally have weak predictive capabilities, especially for more efficient combustion conditions. There is, however, a strong relationship between many intensive optical properties (e.g. single scatter albedo, &#197;ngstrom absorption exponent, mass absorption efficiency) and the organic aerosol-to-black carbon ([OA]&#8201;/&#8201;[BC]) mass ratio over a wider range than previously considered (0.3 to 105). The properties of brown carbon (BrC, i.e. light absorbing organic carbon) also vary with [OA]&#8201;/&#8201;[BC]. The contribution of coating-induced enhancements (i.e. <q>lensing</q> effects) to absorption by black carbon are shown to be negligible for all conditions. The BC-OA mixing state varies strongly with [OA]&#8201;/&#8201;[BC]; the fraction of OA that is internally mixed with BC decreases with [OA]&#8201;/&#8201;[BC] while the relative amount of OA coated on BC increases. In contrast, there is little relationship between many OA bulk chemical properties and [OA]&#8201;/&#8201;[BC], with the O&#8201;:&#8201;C and H&#8201;:&#8201;C atomic ratios and the relative abundance of a key marker ion (m/z&#8201;=&#8201;60, linked to levoglucosan) all showing no dependence on [OA]&#8201;/&#8201;[BC]. In contrast, both the organic nitrate fraction of OA and the OA volatility do depend on the [OA]&#8201;/&#8201;[BC]. Neither the total particle or BC-specific size distributions exhibit any clear dependence on the burn conditions or [OA]&#8201;/&#8201;[BC], although there is perhaps a dependence on fuel type. Overall, our results expand on existing knowledge to contribute new understanding of the properties of particles emitted from biomass combustion.

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Section: Oa Composition and Volatilitymentioning

confidence: 99%

Biomass-burning derived particles from a wide variety of fuels: Part 1: Properties of primary particles

McClure¹,

Lim²,

Hagan³

et al. 2019

Preprint

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“…Aerosol from wildfires is dominated by organic compounds by mass. 51 A recent study on the evolution in the stratosphere of the smoke from 2017 western Canadian wildfires found a reduction of the smoke life time of 40% attributed to photochemical loss of organic carbon. 52 Due to a delayed arrival of the smoke to altitude range investigasted, 52 that study may not fully include approximately the first month of smoke evolution.…”

Section: Discussionmentioning

confidence: 99%

Formation and composition of the UTLS aerosol

et al. 2019

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Stratospheric aerosol has long been seen as a pure mixture of sulfuric acid and water. Recent measurements, however, found a considerable carbonaceous fraction extending at least 8 km into the stratosphere. This fraction affects the aerosol optical depth (AOD) and the radiative properties, and hence the radiative forcing and climate impact of the stratospheric aerosol. Here we present an investigation based on a decade (2005-2014) of airborne aerosol sampling at 9-12 km altitude in the tropics and the northern hemisphere (NH) aboard the IAGOS-CARIBIC passenger aircraft. We find that the chemical composition of tropospheric aerosol in the tropics differs markedly from that at NH midlatitudes, and, that the carbonaceous stratospheric aerosol is oxygenpoor compared to the tropospheric aerosol. Furthermore, the carbonaceous and sulfurous components of the aerosol in the lowermost stratosphere (LMS) show strong increases in concentration connected with springtime subsidence from overlying stratospheric layers. The LMS concentrations significantly exceed those in the troposphere, thus clearly indicating a stratospheric production of not only the well-established sulfurous aerosol, but also a considerable but less understood carbonaceous component.npj Climate and Atmospheric Science (2019)2:40 ; https://doi.

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“…2.3) with transport and chemistry time steps of 5 and 10 min, respectively. GEOS-Chem employs SO 2− 4 -NO − 3 -NH + 4 thermodynamics (Fountoukis and Nenes, 2007) coupled to an ozone-VOC-NO x -oxidant chemical mechanism (Mao et al, 2013;Travis et al, 2016;Miller et al, 2017) with integrated Cl-Br-I chemistry (Sherwen et al, 2016). The model includes schemes for fine and coarse sea salt aerosols (Jaeglé et al, 2011) and mineral dust in four size bins (Fairlie et al, 2007;Ridley et al, 2012).…”

Section: The Geos-chem Modelmentioning

confidence: 99%

“…Recent studies demonstrate that there is no clear consensus on the magnitude of SOA from fires, with estimates that range from virtually none to 95 Tg yr −1 (Shrivastava et al, 2017;Vakkari et al, 2018). Much of this spread comes from diverging results from field versus laboratory studies: the majority of field studies have reported no secondary aerosol formation (above dilution-corrected POA concentrations; Hodshire et al, 2019) or even a decrease in OA (May et al, 2014(May et al, , 2015Liu et al, 2016;Akagi et al, 2012;Jolleys et al, 2012;Forrister et al, 2015;Collier et al, 2016;Garofalo et al, 2019), while a few field studies observed significant SOA formation from biomass burning emissions (Yokelson et al, 2009;Vakkari et al, 2014Vakkari et al, , 2018. Laboratory studies, on the contrary, almost always report substantial SOA formation from fires (Grieshop et al, 2009;Hennigan et al, 2011;Ortega et al, 2013;Tkacik et al, 2017;Lim et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…Biomass burning in Alaska has also accelerated in the last decade through increases in both burned area and fire frequency leading to increases in carbon loss associated with late-season burning (Turetsky et al, 2011). Both relative and total impacts of BB on air quality and climate forcing are expected to increase as controls continue to reduce fossil fuel emissions and a changing climate potentially leads to more fires (Fuzzi et al, 2015;Val Martin et al, 2015). It is there-fore becoming increasingly important to have models and emission inventories that can accurately characterize the impact that current and future fires and their emitted aerosols have on the environment, climate, and human health.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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

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Emission and Evolution of Submicron Organic Aerosol in Smoke from Wildfires in the Western United States

Cited by 126 publications

References 59 publications

Biomass-burning derived particles from a wide variety of fuels: Part 1: Properties of primary particles

Biomass-burning derived particles from a wide variety of fuels: Part 1: Properties of primary particles

Formation and composition of the UTLS aerosol

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

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