Secondary Organic Aerosol Formation from m-Xylene in the Absence of NO sub(x)

• Published in: Environmental science & technology Vol. 41; no. 21; pp. 7409 - 7416
• Main Authors: Song, Chen, Na, Kwangsam, Warren, Bethany, Malloy, Quentin, Cocker III, David R
• Format: Journal Article
• Language: English
• Published: 01.01.2007
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es070429r

Formation of secondary organic aerosol (SOA) from m-xylene photoxidation in the absence of NO sub(x) was investigated in a series of smog chamber experiments. Experiments were performed in dry air and in the absence of seed aerosol with H sub(2)O sub(2) photolysis providing a stable hydroxyl radical (OH radical) source. SOA formation from this study is exceptionally higher than experiments with existence of NO sub(x). The experiments with elevated HO sub(2) levels indicate that organic hydroperoxide compounds should contribute to SOA formation. Nitrogen oxide (NO) is shown to reduce aerosol formation; the constant aerosol formation rate obtained before addition of NO and after consumption of NO strongly suggests that aerosol formation is mainly through reactions with OH and HO sub(2) radicals. In addition, a density of 1.40 plus or minus 0.1 g cm super(-3) for the SOA from the photooxidation of m-xylene in the absence of NOdx has been measured, which is significantly higher than the currently used unit density.