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Proc Natl Acad Sci U S A

Title:		Contribution of isoprene-derived organosulfates to free tropospheric aerosol mass
Author(s):		Froyd KD; Murphy SM; Murphy DM; de Gouw JA; Eddingsaas NC; Wennberg PO;
Address:		"Chemical Sciences Division, National Oceanic and Atmospheric Administration Earth System Research Laboratory, Boulder, CO 80305, USA. Karl.Froyd@noaa.gov"
Journal Title:		Proc Natl Acad Sci U S A
Year:		2010
Volume:		20101122
Issue:		50
Page Number:		21360 - 21365
DOI:		10.1073/pnas.1012561107
ISSN/ISBN:		1091-6490 (Electronic) 0027-8424 (Print) 0027-8424 (Linking)
Abstract:		"Recent laboratory studies have demonstrated that isoprene oxidation products can partition to atmospheric aerosols by reacting with condensed phase sulfuric acid, forming low-volatility organosulfate compounds. We have identified organosulfate compounds in free tropospheric aerosols by single particle mass spectrometry during several airborne field campaigns. One of these organosulfates is identified as the sulfate ester of IEPOX, a second generation oxidation product of isoprene. The patterns of IEPOX sulfate ester in ambient data generally followed the aerosol acidity and NO(x) dependence established by laboratory studies. Detection of the IEPOX sulfate ester was most sensitive using reduced ionization laser power, when it was observed in up to 80% of particles in the tropical free troposphere. Based on laboratory mass calibrations, IEPOX added > 0.4% to tropospheric aerosol mass in the remote tropics and up to 20% in regions downwind of isoprene sources. In the southeastern United States, when acidic aerosol was exposed to fresh isoprene emissions, accumulation of IEPOX increased aerosol mass by up to 3%. The IEPOX sulfate ester is therefore one of the most abundant single organic compounds measured in atmospheric aerosol. Our data show that acidity-dependent IEPOX uptake is a mechanism by which anthropogenic SO(2) and marine dimethyl sulfide emissions generate secondary biogenic aerosol mass throughout the troposphere"
Keywords:		Aerosols/*analysis Air Pollutants/*analysis Atmosphere/chemistry Butadienes/*chemistry Hemiterpenes/*chemistry Hydrogen-Ion Concentration Mass Spectrometry/methods Organic Chemicals/*analysis Oxidation-Reduction Pentanes/*chemistry Sulfates/*analysis Unit;
Notes:		"MedlineFroyd, K D Murphy, S M Murphy, D M de Gouw, J A Eddingsaas, N C Wennberg, P O eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. 2010/11/26 Proc Natl Acad Sci U S A. 2010 Dec 14; 107(50):21360-5. doi: 10.1073/pnas.1012561107. Epub 2010 Nov 22"