The accurate characterization of atmospheric carbonaceous particulate matter in real time is currently limited by (1) sampling artifacts from semi-volatile organic compounds that adsorb and desorb from the collection media, and (2) the lack of instrumentation for determining the particulate oxygen associated with particulate organic carbon, the particulate mass along with organic and elemental (black) carbon, and the mass balance for particulate carbon and oxygen.  This project will construct and validate an artifact-free, real-time, organic and elemental (black) carbon analyzer.  Prototype instruments will be built with capabilities for the simultaneous real-time determination of particulate organic oxygen and mass, as well as carbon, in several size fractions.  In Phase I, compact selective inlets and diffusion denuders will be incorporated into an existing real-time portable instrument for particulate carbon.  The resulting instrumentation will be evaluated, modified if necessary, and validated using well-characterized, dilute combustion and ambient aerosols in environmental chambers.  Proof-of-concept also will be established for a related technique for particulate organic oxygen, along with parallel mass monitoring.

Commercial Applications and Other Benefits as described by awardee:  The Department of Energy is concerned about decreasing the uncertainty in the modeling of how organic and black (elemental) carbon influence climate change.  Instrumentation for the real-time monitoring of particulate carbon, oxygen, and mass should provide better data for this purpose and also should benefit the U.S. Environmental Protection Agency’s efforts to understand the health effects of human exposure to airborne fine particles.