Brown Carbon Light Absorption from Wildfire Plumes Related to Low-volatility Organic and Nitrogen-containing Organic Compounds
NISHIT SHETTY, Pai Liu, Yutong Liang, Benjamin Sumlin, Conner Daube, Scott Herndon, Allen Goldstein, Rajan K. Chakrabarty,
Washington University in St. Louis Abstract Number: 206
Working Group: Carbonaceous Aerosol
AbstractLight absorbing organic aerosol emissions—known as brown carbon (BrC)—can act as short-term climate forcers, and they modify the Earth’s radiative budget by interacting with incoming solar radiation. Conventionally, a majority of light absorption by BrC is attributed to specific chemical compound groups such as nitroaromatics and polyaromatic hydrocarbons. Evidence from laboratory studies suggests that low volatility organics, primarily emitted during high-temperature combustion, could contribute significantly to light absorption by BrC aerosols. In this talk, we will present our results on the spectral light absorption properties of BrC aerosol emissions from three wildfires across the western United States. sampled as part of the 2019 Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) field campaign. We observed that both the extremely low volatility organic carbon and nitrogen-containing organic compound concentration were associated with an increase in BrC light absorption. We also observed that a significant fraction of the BrC was water-insoluble, with water-insoluble BrC comprising at least 43 ± 11% of the total BrC light absorption.