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Effective absorption cross sections and photolysis rates of anthropogenic and biogenic secondary organic aerosols.
- Source :
-
Atmospheric Environment . Apr2016, Vol. 130, p172-179. 8p. - Publication Year :
- 2016
-
Abstract
- Mass absorption coefficient (MAC) values were measured for secondary organic aerosol (SOA) samples produced by flow tube ozonolysis and smog chamber photooxidation of a wide range of volatile organic compounds (VOC), specifically: α-pinene, β-pinene, β-myrcene, d-limonene, farnesene, guaiacol, imidazole, isoprene, linalool, ocimene, p-xylene, 1-methylpyrrole, and 2-methylpyrrole. Both low-NO x and high-NO x conditions were employed during the chamber photooxidation experiments. MAC values were converted into effective molecular absorption cross sections assuming an average molecular weight of 300 g/mol for SOA compounds. The upper limits for the effective photolysis rates of SOA compounds were calculated by assuming unity photolysis quantum yields and convoluting the absorption cross sections with a time-dependent solar spectral flux. A more realistic estimate for the photolysis rates relying on the quantum yield of acetone was also obtained. The results show that condensed-phase photolysis of SOA compounds can potentially occur with effective lifetimes ranging from minutes to days, suggesting that photolysis is an efficient and largely overlooked mechanism of SOA aging. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 13522310
- Volume :
- 130
- Database :
- Academic Search Index
- Journal :
- Atmospheric Environment
- Publication Type :
- Academic Journal
- Accession number :
- 113403321
- Full Text :
- https://doi.org/10.1016/j.atmosenv.2015.10.019