This project will characterize the gas and particle phase semi-volatile organic compounds (SVOC) and the gas-phase volatile organic compounds (VOC) emitted by fires using a newly available, on-line, high resolution, high specificity, high sensitivity Proton-Transfer Time-Of-Flight Mass Spectrometer (PTR-TOF-MS). Many reactive SVOC and VOC will be identified and quantified than ever before to better characterize the overall chemical and physical properties of smoke, to better understand the major transformations observed in biomass burning plumes, and to improve photochemical models. Three main activities will be undertaken: (1) High quality simulations of important fire types in a large-scale biomass burning simulation facility maintained by the United States Forest Service (USFS). (2) Quantification of the changes in the VOC, and both the gas and particle phase SVOC, during the first 3 to 4 hours of biomass smoke aging in the University of California, Riverside atmospheric simulation chamber in conjunction with high-resolution aerosol mass spectrometry and many other measurements. (3) Installation in a mobile lab with other instruments for exploratory field measurements of the emissions from aircraft during take-off and landing as well as from vegetation, garbage burning, and geothermal sources.
The project will lead to more accurate estimates of the emissions from one of Earth's largest sources of trace gases and particles, biomass burning. In particular, new data will be available for ozone and aerosol precursors, which are of great interest to atmospheric modelers and air quality officials. The experiments will measure the emissions of two important biomass burning tracers (hydrogen cyanide and acetonitrile) from the second and fourth largest types of biomass burning (cooking fires and crop residue fires, respectively). The tracers can be used for source apportionment, which can lead to improved air shed management. The chemical speciation, smoke evolution, and source attribution aspects are all relevant to public health, regional visibility, and climate. The project will support a graduate student who will carry out the measurements and will also explore the broader impact of the most significant new data within the framework of the GEOS-Chem global chemistry transport model. Collaborations will involve other institutions such as University of California, Riverside, Montana State University, the U.S. Geological Survey, and the U.S. Forest Service.
