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J Phys Chem A

Title:		"Formation yields of glyoxal and methylglyoxal from the gas-phase OH radical-initiated reactions of toluene, xylenes, and trimethylbenzenes as a function of NO2 concentration"
Author(s):		Nishino N; Arey J; Atkinson R;
Address:		"Air Pollution Research Center, University of California, Riverside, California 92521, USA"
Journal Title:		J Phys Chem A
Year:		2010
Volume:		114
Issue:		37
Page Number:		10140 - 10147
DOI:		10.1021/jp105112h
ISSN/ISBN:		1520-5215 (Electronic) 1089-5639 (Linking)
Abstract:		"Aromatic hydrocarbons comprise 20% of non-methane volatile organic compounds in urban areas and are transformed mainly by atmospheric chemical reactions with OH radicals during daytime. In this work we have measured the formation yields of glyoxal and methylglyoxal from the OH radical-initiated reactions of toluene, xylenes, and trimethylbenzenes over the NO2 concentration range (0.2-10.3) x 1013 molecules cm(-3). For toluene, o-, m-, and p-xylene, and 1,3,5-trimethylbenzene, the yields showed a dependence on NO2, decreasing with increasing NO2 concentration and with no evidence for formation of glyoxal or methylglyoxal from the reactions of the OH-aromatic adducts with NO2. In contrast, for 1,2,3- and 1,2,4-trimethylbenzene the glyoxal and methylglyoxal formation yields were independent of the NO2 concentration within the experimental uncertainties. Extrapolations of our results to NO2 concentrations representative of the ambient atmosphere results in the following glyoxal and methylglyoxal yields, respectively: for toluene, 26.0 +/- 2.2% and 21.5 +/- 2.9%; for o-xylene, 12.7 +/- 1.9% and 33.1 +/- 6.1%; for m-xylene, 11.4 +/- 0.7% and 51.5 +/- 8.5%; for p-xylene, 38.9 +/- 4.7% and 18.7 +/- 2.2%; for 1,2,3-trimethylbenzene, 4.7 +/- 2.4% and 15.1 +/- 3.3%; for 1,2,4-trimethylbenzene, 8.7 +/- 1.6% and 27.2 +/- 8.1%; and for 1,3,5-trimethylbenzene, 58.1 +/- 5.3% (methylglyoxal)"
Keywords:		Benzene Derivatives/*chemistry Gases/chemistry Glyoxal/*chemical synthesis/chemistry Hydroxyl Radical/*chemistry Molecular Structure Nitrogen Dioxide/*analysis Toluene/*chemistry Xylenes/*chemistry;
Notes:		"MedlineNishino, Noriko Arey, Janet Atkinson, Roger eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. 2010/09/02 J Phys Chem A. 2010 Sep 23; 114(37):10140-7. doi: 10.1021/jp105112h"