Composition of Individual Particles Segregated According to Electrical Mobility, Hygroscopicity, Volatility and Mass

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A commercially available Aerosol Time of Flight Mass Spectrometer (ATOFMS) will be used to measure the composition of particles that have been preclassified according to various physical properties. These measurements will provide new insights into the physical/chemical properties and mixing characteristics of atmospheric particles. Such information is valuable for interpreting data from more conventional instrumentation and can be used to evaluate state-of-the-art models that describe the evolution of aerosols from various sources as a function of size and composition. Particles will be classified according to electrical mobility (size) with a differential mobility analyzer (DMA), size and hygroscopicity with a tandem differential mobility analyzer (TDMA), or size with a DMA or TDMA and mass with an Aerosol Particle Mass Analyzer (APM). The effect of volatilization on composition will be studied by heating size-classified particles before analyzing them with the ATOFMS.The first two years of the project will focus on studies with laboratory aerosols of known composition and on the development of sampling protocols for field measurements. An intensive field campaign will be carried out in Atlanta, GA. This project represents a collaboration between the University of Minnesota and Carleton College.