CAREER: Origin and Evolution of the Light Absorption of Biomass Burning Aerosol

Oklahoma State University, Stillwater OK

Investigators

Abstract

This CAREER project is focused an investigation of the origin and evolution of light absorption from biomass burning aerosol. Biomass burning aerosol includes a wide range of organic compounds that may vary with fuel species and combustion conditions. The absorptivity of organic aerosol is known to change during aging in the atmosphere due to a wide variety of chemical and physical processes. Biomass burning aerosol contributes to poor air quality and can alter the radiative balance and impact climate. The goal of this project is to better understand the impacts of biomass burning aerosols on air quality and the climate system. This effort involves a laboratory study of the initial and evolving light-absorbing properties of brown carbon as biomass burning emissions undergo processes such as irradiation, oxidation, and incorporation into the aqueous or organic phases of the aerosol. The focus will be on aerosol emitted from fires in the US Southern Great Plains (SGP) region, where the landscape includes grasses and some woody species, such as eastern red cedar. Achieving the objectives of the project involves the following tasks: (1) prepare biomass burning organic aerosol (BBOA) from under-explored fuel species relevant to the SGP location and determine its light absorption; (2) determine the spectroscopic and thermodynamic parameters dictating light absorption by individual BBOA chromophores and their complexes and oligomers; (3) determine the effects of atmospheric aging on the light absorption of biomass burning aerosol, including the chemical processing of BBOA and the physical processing of black carbon. Together, these tasks will enable fundamental insights into the origin and fate of light absorption by biomass burning aerosol. Education and outreach activities include creating publicly available online visualizations of atmospheric chemistry concepts, conducting demonstrations of atmospheric processes at a museum and within selected university programs, and establishing a research rotation with students. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.