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Proc Natl Acad Sci U S A

Title:		In situ measurements of gas/particle-phase transitions for atmospheric semivolatile organic compounds
Author(s):		Williams BJ; Goldstein AH; Kreisberg NM; Hering SV;
Address:		"Department of Environmental Science, Policy, and Management, University of California, 147 Mulford Hall, Berkeley, CA 94720, USA. brentw@me.umn.edu"
Journal Title:		Proc Natl Acad Sci U S A
Year:		2010
Volume:		20100208
Issue:		15
Page Number:		6676 - 6681
DOI:		10.1073/pnas.0911858107
ISSN/ISBN:		1091-6490 (Electronic) 0027-8424 (Print) 0027-8424 (Linking)
Abstract:		"An understanding of the gas/particle-phase partitioning of semivolatile compounds is critical in determining atmospheric aerosol formation processes and growth rates, which in turn affect global climate and human health. The Study of Organic Aerosol at Riverside 2005 campaign was performed to gain a better understanding of the factors responsible for aerosol formation and growth in Riverside, CA, a region with high concentrations of secondary organic aerosol formed through the phase transfer of low-volatility reaction products from the oxidation of precursor gases. We explore the ability of the thermal desorption aerosol gas chromatograph (TAG) to measure gas-to-particle-phase transitioning for several organic compound classes (polar and nonpolar) found in the ambient Riverside atmosphere by using in situ observations of several hundred semivolatile organic compounds. Here we compare TAG measurements to modeled partitioning of select semivolatile organic compounds. Although TAG was not designed to quantify the vapor phase of semivolatile organics, TAG measurements do distinguish when specific compounds are dominantly in the vapor phase, are dominantly in the particle phase, or have both phases present. Because the TAG data are both speciated and time-resolved, this distinction is sufficient to see the transition from vapor to particle phase as a function of carbon number and compound class. Laboratory studies typically measure the phase partitioning of semivolatile organic compounds by using pure compounds or simple mixtures, whereas hourly TAG phase partitioning measurements can be made in the complex mixture of thousands of polar/nonpolar and organic/inorganic compounds found in the atmosphere"
Keywords:		"Aerosols *Atmosphere Calibration Chemistry, Organic/methods Chromatography, Gas/methods Environmental Monitoring/methods Gases Hot Temperature Mass Spectrometry/methods Naphthalenes/chemistry Organic Chemicals/*chemistry Oxygen/chemistry Particle Size Pht;"
Notes:		"MedlineWilliams, Brent J Goldstein, Allen H Kreisberg, Nathan M Hering, Susanne V eng Research Support, Non-U.S. Gov't 2010/02/10 Proc Natl Acad Sci U S A. 2010 Apr 13; 107(15):6676-81. doi: 10.1073/pnas.0911858107. Epub 2010 Feb 8"