Molecular Structure and Microstructure of PM2.5 Derived from Stationary and Mobile Fossil Fuel Sources

This Collaborative Research Activities in Environmental Molecular Science (CRAEMS) Award to the University of Kentucky is supported by the Special Projects Office in the Chemistry Division, and is in support of the work of Gerald Huffman and his collaborators in environmental chemistry. Support is also provided to J. David Robinson at the University of Missouri-Columbia, and Ronald Pugmire and Adel Sarofim at the University of Utah through subawards. The research will focus on fine airborne particular matter (PM) of less than 2.5 microns in diameter, derived from the combustion of fossil fuels in both stationary and mobile sources. These particulates are complex mixtures of ammonium sulfate, ammonium nitrate, carbon, both elemental and organic, and inorganic constituents, particularly metals. The program will have three goals: (1) to identify molecular structure and microstructure, relevant for source apportionment; (2) to identify components that have significant effects on human health; and (3) to achieve, through laboratory experiments and modeling, a basic understanding of the formation mechanisms of critical structures identified. Molecular and microstructures will be characterized by a variety of spectroscopic and microscopic techniques including XAFS, GC-MS, 13C-NMR, SEM, TEM, XRF and Mossbauer spectroscopy. Samples will be obtained from large-scale combustion facilities and diesel truck sampling, laboratory experiments and ambient air sampling. The Environmental Protection Agency has proposed new regulations for fine airborne particulates. The knowledge generated by this research will be valuable for both the establishment of appropriate regulations for particulates and for compliance with those regulations.