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Particulate matter and black carbon optical properties and emission factors from prescribed fires in the southeastern United States
Citation:
Holder, A., G. Hagler, J. Aurell, M. Hays, AND B. Gullett. Particulate matter and black carbon optical properties and emission factors from prescribed fires in the southeastern United States. JOURNAL OF GEOPHYSICAL RESEARCH: ATMOSPHERES. American Geophysical Union, Washington, DC, 121(7):3465-3483, (2016).
Impact/Purpose:
Open burning of biomass accounts for 32% of the US PM2.5 emissions and are the largest source of black carbon in the US. Biomass burning can lead to degradations in air quality and may increase radiatiave forcing in the atmosphere. However, there are very few measurements of the aerosol optical properties from biomass burning in the field and there has been no assessment of the ability of lab burns to represent the field measurements. This study measured aerosol optical properties, black carbon, and PM emissions from prescribed fires in the southeastern United States and lab burns of the same fuels to determine the representativeness of aerosol optical properties derived from lab simulations.
Description:
The aerosol emissions from prescribed fires in the Southeastern United States were measured and compared to emissions from laboratory burns with fuels collected from the site. Fine particulate matter (PM2.5), black carbon, and aerosol light scattering and absorption were characterized for each burn. Black carbon emission factors measured at ground level and aloft were similar and comparable to those measured from laboratory burns. However, PM emission factors were almost an order of magnitude lower measured by aircraft compared to those measured on the ground. The large difference in PM emission factors is suspected to be due measurement differences and to the partitioning of organic compounds to the gas phase as the plume dilutes. The higher intensity prescribed fires had PM emission factors greater than the other prescribed fires and were comparable with values reported for smoldering emissions in the literature. The absorption angstrom exponents (αa) for the high intensity fires were larger than the other prescribed fires, implying larger brown carbon emissions from higher intensity fires. There was no consistent comparison for αa and the single scattering albedo (ω) between the lab and field measurements for two different measurement campaigns.
