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J Phys Chem A

Title:		Secondary organic aerosol formation from low-NO(x) photooxidation of dodecane: evolution of multigeneration gas-phase chemistry and aerosol composition
Author(s):		Yee LD; Craven JS; Loza CL; Schilling KA; Ng NL; Canagaratna MR; Ziemann PJ; Flagan RC; Seinfeld JH;
Address:		"Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California 91125, United States"
Journal Title:		J Phys Chem A
Year:		2012
Volume:		20120410
Issue:		24
Page Number:		6211 - 6230
DOI:		10.1021/jp211531h
ISSN/ISBN:		1520-5215 (Electronic) 1089-5639 (Linking)
Abstract:		"The extended photooxidation of and secondary organic aerosol (SOA) formation from dodecane (C(12)H(26)) under low-NO(x) conditions, such that RO(2) + HO(2) chemistry dominates the fate of the peroxy radicals, is studied in the Caltech Environmental Chamber based on simultaneous gas and particle-phase measurements. A mechanism simulation indicates that greater than 67% of the initial carbon ends up as fourth and higher generation products after 10 h of reaction, and simulated trends for seven species are supported by gas-phase measurements. A characteristic set of hydroperoxide gas-phase products are formed under these low-NO(x) conditions. Production of semivolatile hydroperoxide species within three generations of chemistry is consistent with observed initial aerosol growth. Continued gas-phase oxidation of these semivolatile species produces multifunctional low volatility compounds. This study elucidates the complex evolution of the gas-phase photooxidation chemistry and subsequent SOA formation through a novel approach comparing molecular level information from a chemical ionization mass spectrometer (CIMS) and high m/z ion fragments from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Combination of these techniques reveals that particle-phase chemistry leading to peroxyhemiacetal formation is the likely mechanism by which these species are incorporated in the particle phase. The current findings are relevant toward understanding atmospheric SOA formation and aging from the 'unresolved complex mixture,' comprising, in part, long-chain alkanes"
Keywords:
Notes:		"PubMed-not-MEDLINEYee, Lindsay D Craven, Jill S Loza, Christine L Schilling, Katherine A Ng, Nga Lee Canagaratna, Manjula R Ziemann, Paul J Flagan, Richard C Seinfeld, John H eng 2012/03/20 J Phys Chem A. 2012 Jun 21; 116(24):6211-30. doi: 10.1021/jp211531h. Epub 2012 Apr 10"