Characteristics and sources of oxygenated VOCs in Hong Kong: Implications for ozone formation

Fanglin Wang; Steven Sai Hang Ho; Chung Ling Man; Linli Qu; Zhe Wang; Zhi Ning; Kin Fai Ho

doi:10.1016/j.scitotenv.2023.169156

Characteristics and sources of oxygenated VOCs in Hong Kong: Implications for ozone formation

Sci Total Environ. 2024 Feb 20:912:169156. doi: 10.1016/j.scitotenv.2023.169156. Epub 2023 Dec 6.

Authors

Fanglin Wang¹, Steven Sai Hang Ho², Chung Ling Man¹, Linli Qu³, Zhe Wang⁴, Zhi Ning⁴, Kin Fai Ho⁵

Affiliations

¹ JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong.
² Division of Atmospheric Sciences, Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89512, United States; Hong Kong Premium Services and Research Company, Lai Chi Kok, Hong Kong; Shenzhen Voltech Analytical and Technology Center, Futian, Shenzhen, China.
³ Hong Kong Premium Services and Research Company, Lai Chi Kok, Hong Kong; Shenzhen Voltech Analytical and Technology Center, Futian, Shenzhen, China.
⁴ Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong.
⁵ JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong. Electronic address: kfho@cuhk.edu.hk.

PMID: 38065490
DOI: 10.1016/j.scitotenv.2023.169156

Abstract

To investigate the characteristics of oxygenated volatile organic compounds (OVOCs) and their potential contribution to ozone (O₃) generation, we conducted 3-h high-resolution observations during the summertime of 2022 and the wintertime of 2021. This study focused on a total of 28 OVOCs in five different chemical classes, which were encompassed at two representative sites in Hong Kong, including a roadside and an urban area. During the summertime, the total concentrations of quantified OVOCs (∑_OVOCs) were 45 ± 12 and 63 ± 20 μg m^-3 at the roadside and urban sites, respectively, whereas the ∑_OVOCs decreased by 31 ± 11 % and 38 ± 13 %, respectively, during the wintertime. Among the classes of OVOCs, carbonyls and alcohols were the two predominant at both sites, with relatively higher concentration levels of acetone, methanol, butanaldehyde, and acrolein. The sources of OVOCs have significant spatial and temporal characteristics. Spatially, OVOCs were predominately attributed to primary emission and background at the roadside site, whereas they were a combination of primary emission, secondary formation, and background at the urban site. Temporally, background sources dominated the summertime OVOCs, while the contribution of primary emissions increased for the wintertime OVOCs. The O₃ formation potential (OFP) for the OVOCs was calculated. The OFPs were 67 ± 16 and 119 ± 31 μg m^-3 at the roadside and urban sites during the summertime, whereas the winter OFPs declined 30 % at the roadside and 38 % at the urban site. The background sources of carbonyls and alcohols at the roadside and of carbonyls and acrylates in the urban area were the major contributors to the summer OFP. Controlling the OVOC sources from local non-combustion sources such as gasoline-fuel evaporation and volatile chemical-containing products could lead to a reduction of OVOCs in the background and subsequently mitigate the OFP. This is beneficial for local O₃ reduction in Hong Kong and surrounding regions.

Keywords: Oxygenated volatile organic compounds (OVOCs); Ozone formation potential (OFP); Source distribution.