Atmospheric particles exert an influence on regional and global climate by absorbing and scattering solar radiation. Absorption by black carbon (BC) and brown carbon (BrC, aka absorbing organic carbon) can contribute nearly as much to global radiative forcing as CO2. However, the uncertainties in the absolute and relative BC and BrC contributions are substantial. Biomass burning—both open burning and residential burning—are the major global source of BC and BrC. Yet there remain important questions about the properties of biomass burning emissions given the diversity of fuel types and burn conditions. Further, there is limited understanding about how biomass burning smoke, that is the mix of emitted particles and gases, evolve upon photochemical processing in the atmosphere. To address this, we carried out a suite of photochemical aging experiments on smoke produced from combustion of a wide variety of fuel types under various burn conditions. This “FIREX” study provides a comprehensive look at how chemical processing in smoke plumes alters the optical properties and composition of biomass burning-derived particles, and how this depends on the fuel burned. This work provides new constraints for representing the atmospheric variability and evolution of BC and BrC in models.
Photochemical processing of biomass burning smoke: influence on optical and chemical properties of particles
Atmospheric & Environmental Chemistry Seminar
Prof. Chris Cappa, UC Davis
Friday, December 7, 2018 - 12:00pm
Kelvin Bates, Adam Birdsall