COLLABORATIVE RESEARCH: Chlorine Activation in Biomass Burning Plumes

University Of Washington, Seattle WA

Investigators

Abstract

This project is a collaborative effort to investigate the emissions of particulate chloride from biomass burning and the implications of these emissions on the formation of atmospheric ozone and small particles. The effort combines the facilities and expertise of atmospheric chemists at Carnegie-Mellon University (CMU) and University of Washington (UW) for the purpose of conducting a detailed set of laboratory experiments in a large smog chamber reactor in CMU's combustion facility. The chamber will be filled with smoke from the open combustion of globally relevant chloride emitting biomass fuels such as various types of grasses (e.g. Sawgrass, Wiregrass, Rice straw), and Palmetto (small palm species). Changes in the concentrations of gas-phase reactants and products will be determined in real-time using UW's state-of-the-art chemical measurement instrumentation. The investigators will apply kinetic box models to derive the combination of parameters that give the best measurement-model agreement for the development of parameters that can be used in regional and global models. Particulate chloride undergoes efficient reactions with nitrogen oxide gases, releasing nitryl chloride (ClNO2) in the gas phase. The presence of ClNO2 can significantly perturb the troposphere's oxidant budget, the cycling of chlorine (ClOx), hydrogen (HOx), and NOx radicals, the oxidation of organic compounds and associated organic aerosol formation, and ground-level ozone levels. This project will be the first laboratory study to investigate the formation and yield of ClNO2 from dinitrogen pentoxide (N2O5), reacting with chloride in particle systems representative of biomass burning aerosols.