Relative contributions of selected multigeneration products to chamber SOA formed from photooxidation of a range (C10–C17) of n-alkanes under high NOx conditions. (1st January 2021)

• Record Type: Journal Article
• Authors: Docherty, Kenneth S.; Yaga, Robert; Preston, William T.; Jaoui, Mohammed; Reidel, Theran P.; Offenberg, John H.; Kleindienst, Tadeusz E.; Lewandowski, Michael
• Is Part Of: Atmospheric environment. Volume 244(2021)
• Publication Date: 2021-01-01
• Subjects: n-alkane -- Secondary organic aerosol -- AMS -- Relative humidity -- Smog chamber; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2020.117976
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: A series of chamber experiments was conducted to investigate the composition of secondary organic aerosol (SOA) following oxidation of a range of parent n -alkanes (C10 –C17 ) in the presence of NO x . The relative contribution of selected species representing first, second, and higher generation products to SOA mass was measured using a high-resolution aerosol mass spectrometer. Gas chromatography was also used for a limited set of amenable species. Relative contributions varied substantially across the range of investigated alkanes reflecting slight changes in SOA composition. The contribution of first-generation cyclic hemiacetal is minimal toward the small end of the investigated range and gradually increases with n -alkane size. The relative contributions of second generation and higher nitrate-containing species, in contrast, decrease with an increased alkane size. A similar trend is observed for relative contribution of organonitrates to SOA. Finally, SOA yield and composition are sensitive to water vapor concentrations. This sensitivity is limited to a narrow range (dry to ~15% RH) with little, if any, impact above 15% suggesting that this impact may be negligible under ambient conditions. The impact of water vapor also appears to decrease with increasing alkane carbon number. Highlights: Smog chamber oxidation of homologous series of n -alkanes in the presence of NO x . On-line measurements of SOA composition by AMS indicate dependence on parent alkane size. Substituted tetrahydrofuran contributions decrease as alkane size increases. Increased water vapor decreases reactive uptake of 1, 4-hydroxycarbonyls. Impact of water vapor on SOA yield and composition occurs at very low RH values.