Origins of formaldehyde in a mountainous background atmosphere of southern China

Qinqin Li; Daocheng Gong; Zijian Chen; Jiangyong Li; Gengchen Wu; Shuo Deng; Hao Wang; Lingyan He; Boguang Wang

doi:10.1016/j.scitotenv.2024.172707

Origins of formaldehyde in a mountainous background atmosphere of southern China

Sci Total Environ. 2024 Apr 23:931:172707. doi: 10.1016/j.scitotenv.2024.172707. Online ahead of print.

Authors

Qinqin Li¹, Daocheng Gong¹, Zijian Chen², Jiangyong Li², Gengchen Wu², Shuo Deng², Hao Wang³, Lingyan He⁴, Boguang Wang⁵

Affiliations

¹ College of Environment and Climate, Jinan University, Guangzhou 511443, China; Guangdong Provincial Observation and Research Station for Atmospheric Environment and Carbon Neutrality in Nanling Forests, China.
² College of Environment and Climate, Jinan University, Guangzhou 511443, China.
³ College of Environment and Climate, Jinan University, Guangzhou 511443, China; Guangdong Provincial Observation and Research Station for Atmospheric Environment and Carbon Neutrality in Nanling Forests, China. Electronic address: wanghao@jnu.edu.cn.
⁴ School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055, China.
⁵ College of Environment and Climate, Jinan University, Guangzhou 511443, China; Guangdong Provincial Observation and Research Station for Atmospheric Environment and Carbon Neutrality in Nanling Forests, China. Electronic address: tbongue@jnu.edu.cn.

PMID: 38657816
DOI: 10.1016/j.scitotenv.2024.172707

Abstract

Formaldehyde (HCHO) is one of the key indicators of severe photochemical pollution and strong atmospheric oxidation capacity in southern China. However, current information on the origins of regional HCHO and the impacts of polluted air masses remains scarce and unclear. In this study, an intensive observation of HCHO was conducted at a mountainous background site in southern China during typical photochemical pollution episodes. The concentrations of HCHO reached up to 6.14 ppbv and averaged at 2.68 ± 1.11 ppbv. Source appointment using a photochemical age-based parameterization method revealed significant contributions of secondary formation (50 %) and biomass burning (42 %). Meanwhile, under the influence of the East Asian Winter Monsoon, polluted air masses from central and western China can significantly increase the regional HCHO levels. The simulation results adopting the Rapid Adaptive Optimization Model for Atmospheric Chemistry model further demonstrated that the intrusion of active anthropogenic pollutants (e.g., small-molecule alkenes) can accelerate the net production rate of HCHO, particularly through BVOC-oxidation pathways. This study suggests a potential enhanced mechanism of HCHO production resulting from anthropogenic-biogenic interactions. It highlights that polluted air masses carrying abundant HCHO from upwind areas may facilitate severe photochemical pollution in the Greater Bay Area.

Keywords: Background atmosphere; Nanling Mountains; ROMAC; Regional photochemical pollution; Regional transport.