Temperature Effects on Secondary Organic Aerosol (SOA) from the Dark Ozonolysis and Photo-Oxidation of Isoprene

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• 作者：Christopher H. Clark ; Mary Kacarab ; Shunsuke Nakao ; Akua Asa-Awuku ; Kei Sato ; David R. Cocker III
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：June 7, 2016
• 年：2016
• 卷：50
• 期：11
• 页码：5564-5571
• 全文大小：405K
• 年卷期：0
• ISSN：1520-5851

文摘

Isoprene is globally the most ubiquitous nonmethane hydrocarbon. The biogenic emission is found in abundance and has a propensity for SOA formation in diverse climates. It is important to characterize isoprene SOA formation with varying reaction temperature. In this work, the effect of temperature on SOA formation, physical properties, and chemical nature is probed. Three experimental systems are probed for temperature effects on SOA formation from isoprene, NO + H₂O₂ photo-oxidation, H₂O₂ only photo-oxidation, and dark ozonolysis. These experiments show that isoprene readily forms SOA in unseeded chamber experiments, even during dark ozonolysis, and also reveal that temperature affects SOA yield, volatility, and density formed from isoprene. As temperature increases SOA yield is shown to generally decrease, particle density is shown to be stable (or increase slightly), and formed SOA is shown to be less volatile. Chemical characterization is shown to have a complex trend with both temperature and oxidant, but extensive chemical speciation are provided.