Chamber studies of secondary organic aerosol growth by reactive uptake of simple carbonyl compounds

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Read Full Article (file size: 393110 bytes) Cited by JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 110, D23207, doi:10.1029/2005JD006004, 2005 Chamber studies of secondary organic aerosol growth by reactive uptake of simple carbonyl compounds Jesse H. Kroll Department of Environmental Science and Engineering, California Institute of Technology, Pasadena, California, USA Nga L. Ng Department of Chemical Engineering, California Institute of Technology, Pasadena, California, USA Shane M. Murphy Department of Chemical Engineering, California Institute of Technology, Pasadena, California, USA Varuntida Varutbangkul Department of Chemical Engineering, California Institute of Technology, Pasadena, California, USA Richard C. Flagan Department of Chemical Engineering, California Institute of Technology, Pasadena, California, USA John H. Seinfeld Departments of Environmental Science and Engineering and Chemical Engineering, California Institute of Technology, Pasadena, California, USA Abstract Recent experimental evidence indicates that heterogeneous chemical reactions play an important role in the gas-particle partitioning of organic compounds, contributing to the formation and growth of secondary organic aerosol in the atmosphere. Here we present laboratory chamber studies of the reactive uptake of simple carbonyl species (formaldehyde, octanal, trans,trans-2,4-hexadienal, glyoxal, methylglyoxal, 2,3-butanedione, 2,4-pentanedione, glutaraldehyde, and hydroxyacetone) onto inorganic aerosol. Gas-phase organic compounds and aqueous seed particles (ammonium sulfate or mixed ammonium sulfate/sulfuric acid) are introduced into the chamber, and particle growth and composition are monitored using a differential mobility analyzer and an Aerodyne Aerosol Mass Spectrometer. No growth is observed for most carbonyls studied, even at high concentrations (500 ppb to 5 ppm), in contrast with the results from previous studies. The single exception is glyoxal (CHOCHO), which partitions into the aqueous aerosol much more efficiently than its Henry's law constant would predict. No major enhancement in particle growth is observed for the acidic seed, suggesting that the large glyoxal uptake is not a result of particle acidity but rather of ionic strength of the seed. This increased partitioning into the particle phase still cannot explain the high levels of glyoxal measured in ambient aerosol, indicating that additional (possibly irreversible) pathways of glyoxal uptake may be important in the atmosphere. Received 21 March 2005; accepted 19 September 2005; published 6 December 2005. Keywords: secondary organic aerosol; heterogeneous reactions; glyoxal. Index Terms: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801, 4906); 0317 Atmospheric Composition and Structure: Chemical kinetic and photochemical properties; 0345 Atmospheric Composition and Structure: Pollution: urban and regional (0305, 0478, 4251); 0365 Atmospheric Composition and Structure: Troposphere: composition and chemistry. Read Full Article (file size: 393110 bytes) Cited by Citation: Kroll, J. H., N. L. Ng, S. M. Murphy, V. Varutbangkul, R. C. Flagan, and J. H. Seinfeld (2005), Chamber studies of secondary organic aerosol growth by reactive uptake of simple carbonyl compounds, J. Geophys. Res., 110, D23207, doi:10.1029/2005JD006004. Copyright 2005 by the American Geophysical Union.

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