Characterization of Carbonaceous Particles: Aerosol Mass Spectrometry and Light Scattering

79508S05 Aerosol particles have important effects on visibility, acid deposition, climate, and human health. A large fraction of the anthropogenic aerosol is generated from energy-related activities, and organic compounds are known to constitute a significant fraction of ambient aerosol mass in many locations. Yet, large uncertainties remain in quantifying the chemical composition and atmospheric transformations of these aerosols, especially with respect to organic particulate matter. Particularly lacking are real-time, size-resolved, quantitative instruments for the identification, speciation, and source apportionment of carbonaceous aerosols. An innovative thermal desorption, time-of-flight aerosol mass spectrometer has been recently developed with capabilities that can fill a critical need for size-resolved, quantitative chemical composition data on aerosol particles. This project will develop and demonstrate a light scattering module for this instrument, which will enable full characterization of carbonaceous components, including their state of mixing (and atmospheric aging) with other chemcial components such inorganics and dust. Phase I will optimize the light scattering system installed in a time-of-flight aerosol mass spectrometer, perform ray tracing calculations to optimize photon collection, develop software to collect and analyze data on individual particles in real-time, quantify the capabilites of the system in the laboratory, and compare the light scattering properties for individual particles with chemical and size information. Commercial Applications and Other Benefits as described by the awardee: The combined aerosol mass spectrometer and light scattering system should provide aerosol measurement capabilities for a variety of monitoring applications beyond the field of atmospheric research. A portable instrument could be employed in industrial processes monitoring and chemical and biological warfare agent identification. The instrument is ideally suited for the characterization and control of aerosol emissions from a variety of industrial and energy production processes which produce aerosol laden exhaust, including semiconductor manufacturing, gas turbines, fluidized bed combustors, diesel combustors, and conventional furnaces.