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Sci Total Environ

Title:		Effect of NO(2) on nocturnal chemistry of isoprene: Gaseous oxygenated products and secondary organic aerosol formation
Author(s):		Chen Y; Tan Y; Zheng P; Wang Z; Zou Z; Ho KF; Lee S; Wang T;
Address:		"Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong 999077, China; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China. Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China; School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, China. Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong 999077, China. Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong 999077, China. Electronic address: z.wang@ust.hk. Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China. The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong 999077, China. Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China. Electronic address: shun-cheng.lee@polyu.edu.hk"
Journal Title:		Sci Total Environ
Year:		2022
Volume:		20220623
Issue:
Page Number:		156908 -
DOI:		10.1016/j.scitotenv.2022.156908
ISSN/ISBN:		1879-1026 (Electronic) 0048-9697 (Linking)
Abstract:		"As one of the most abundant non-methane hydrocarbon in the atmosphere, isoprene has attracted lots of attention on its oxidation processes and environmental effects. However, less is known about the nocturnal chemistry of isoprene with multiple oxidants coexisting in the atmosphere. Besides, though highly oxygenated molecules (HOMs) have recently been recognized to contribute to secondary organic aerosol (SOA) formation, the specific contribution of measured HOMs on SOA formation in isoprene oxidation has not been well established. In this study, the oxidation of isoprene was simulated under dark and various NO(2)/O(3) conditions. Plenty of oxidation products were identified by combining two state-of-the-art time-of-flight mass spectrometers, and more species with high C and N numbers and low volatilities were detected under high NO(2) conditions. The nocturnal oxidation of isoprene was found to be governed by synergic effects of multiple oxidants, including O(3), NO(3)*, and *OH at the same time, and the oxidation proportions changed with NO(2). NO(2) promoted the formation of most N-containing products especially N2 products, because of the decisive role of NO(3)* on their formation. Nevertheless, some products such as C(5)H(10)O(3)(-)(5), C(5)H(11)NO(6), and C(10)H(16)N(2)O(10,11) showed a better correlation with HO(2)NO(2) rather than NO(2)/O(3), indicating the importance of HO(2)* chemistry on the oxidation products formation. Though the concentration of measured oxygenated products was dominated by volatile and semi-volatile organic compounds, the low- and extremely low-volatile organic compounds contributed over 97 % to the SOA formation potential. However, challenges still exist in accurately simulating SOA formation from the measured oxygenated molecules to match the measurement, and further comprehensive characterization of oxidation products in both gas and aerosol phases at the molecular level is needed"
Keywords:		Aerosols/analysis *Air Pollutants/chemistry Butadienes/analysis Gases Hemiterpenes Nitrogen Dioxide Oxidants Oxidation-Reduction *Volatile Organic Compounds Isoprene oxidation Multiple oxidants Oxygenated organic molecules SOA formation Smog chamber ToF-C;
Notes:		"MedlineChen, Yi Tan, Yan Zheng, Penggang Wang, Zhe Zou, Zhouxing Ho, Kin-Fai Lee, Shuncheng Wang, Tao eng Netherlands 2022/06/27 Sci Total Environ. 2022 Oct 10; 842:156908. doi: 10.1016/j.scitotenv.2022.156908. Epub 2022 Jun 23"