HR: 16:00h
AN: A34B-01    [Abstracts]
TI: Aerosol Mass Spectrometry: Morphology and Chemistry of Combustion Particles in the Lab and the Atmosphere
AU: * Worsnop, D R
EM: worsnop@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821
AU: Jayne, J T
AF: Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821
AU: Canagaratna, M R
AF: Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821
AU: Onasch, T B
AF: Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821
AU: Williams, L R
AF: Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821
AU: Slowik, J
AF: Department of Chemistry, Boston College, Chestnut Hill, MA 02167
AU: Davidovits, P
EM: paul.davidovits@bc.edu
AF: Department of Chemistry, Boston College, Chestnut Hill, MA 02167
AU: DeCarlo, P
AF: Program for Atmospheric and Ocean Sciences, University of Colorado, Boulder, CO 80309
AU: Zhang, Q
AF: Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309
AU: Jimenez, J L
EM: jose.jimenez@colorado.edu
AF: Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309
AB: Atmospheric aerosols play important roles in climate, visibility and local air quality. Of particular interest is the contribution of combustion emissions. Here we present results from laboratory and ambient sampling studies that combine aerosol measurements made with an Aerosol Mass Spectrometer (AMS) and a Scanning Mobility Particle Sizer (SMPS). Simultaneous sizing of aerodynamic and mobility diameters enables determination of particle density and shape factors. AMS analysis of organic carbon combined with external measurement of black carbon (BC) provides chemical mass balance. Lab and atmospheric measurements indicate that fresh combustion particles are fractal, becoming more spherical as processing coats particles with condensable vapors. The laboratory experiments sample particles produced in a pre-mixed propane flame. Particles with mobility diameter selected by a Differential Mobility Analyzer (DMA) are then aerodynamically sized and chemically analyzed with the AMS. At low fuel equivalence ratio (<4) fractal (mostly BC) particles are observed while higher fuel ratios nearly spherical particles coated with PAHs are produced. Field results are based on sampling of individual on-road diesel vehicles (New York City-PMTACS 2001; Mexico City-MCMA 2002/2003) and continuous ambient sampling (Pittsburgh-PAQS 2002; Mexico City-MCMA 2003). On-road vehicle particle emissions look very much like the flame produced fractal particles while the ambient measurements show evidence both of fresh and larger, processed particles. Recent lab studies are simulating processing via vapor condensation on fractal particles while modeling studies are comparing simultaneous AMS and SMPS ambient measurements.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0365 Troposphere--composition and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting