Abstract View
Chemical Characterization of Organic Nitrogen Aerosol Particles from Prescribed Burns of U.S. Wildland Forests
FARRAH HAERI, Daniel Foster, Deep Sengupta, Afsara Tasnia, Paul Van Rooy, Nathan Kreisberg, Scott Stephens, John Battles, Robert York, Kelley Barsanti, Allen Goldstein, Coty Jen, Carnegie Mellon University
Abstract Number: 714
Working Group: Source Apportionment
Abstract
A significant source of organic nitrogen (ON) compounds in the atmosphere are emitted from biomass burning (BB) events, including wildfires. ON compounds can absorb light, contributing to a warming climate, or deposit onto land and oceans resulting in disruptions of the nitrogen cycle. As wildfire frequency increases in the western U.S., prescribed burning is being implemented U.S wildlands to reduce fuel loading and thus the probability of high-intensity wildfires. However, the implications of these prescribed burning emissions on air quality or environment are not well characterized, especially in regard to the ON contribution from prescribed burning emissions. Thus, to understand the impact large-scale prescribe burning has regional air quality, the chemical composition of ON compounds from prescribed burning emissions needs to be examined.
For this study, we chemically characterize and quantify emission factors (EF) of ON compounds from freshly emitted smoke PM2.5 particles, collected via Sequential Spot Sampler, during prescribed burns (in collaboration with University of California, Berkley (UCB) and Riverside (UCR) at Blodgett Forest Research Station (Georgetown, CA)) using a high-performance liquid chromatographers (HPLC) coupled to an orbitrap mass spectrometer. We find that speciated ON compounds’ (amino acids, nitro vanillin, and nitrocatechols) EF is correlated with the modified combustion efficiency and reflects the prevalence of ON compounds in less efficient burning conditions in the field. In addition, smoke particles were collected downstream of the burn at nighttime compared to near the burn during the day. Certain compounds, such as amino acids, were observed to have higher EFs during nighttime smoldering compared to daytime active burning, suggesting a difference between day and nighttime smoke emissions for ON compounds. Results from this study can be applied toward linking the effects ON compounds from prescribed burning have on the atmosphere and climate.