Pollution mechanisms and photochemical effects of atmospheric HCHO in a coastal city of southeast China

Taotao Liu; Yiling Lin; Jinsheng Chen; Gaojie Chen; Chen Yang; Lingling Xu; Mengren Li; Xiaolong Fan; Fuwang Zhang; Youwei Hong

doi:10.1016/j.scitotenv.2022.160210

Pollution mechanisms and photochemical effects of atmospheric HCHO in a coastal city of southeast China

Sci Total Environ. 2023 Feb 10;859(Pt 1):160210. doi: 10.1016/j.scitotenv.2022.160210. Epub 2022 Nov 14.

Authors

Taotao Liu¹, Yiling Lin², Jinsheng Chen³, Gaojie Chen¹, Chen Yang¹, Lingling Xu⁴, Mengren Li⁴, Xiaolong Fan⁴, Fuwang Zhang⁵, Youwei Hong⁶

Affiliations

¹ Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China; Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China; University of Chinese Academy of Sciences, Beijing, China.
² Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China; College of Chemical Engineering, Huaqiao University, Xiamen, China.
³ Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China; Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China. Electronic address: jschen@iue.ac.cn.
⁴ Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China; Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.
⁵ Environmental Monitoring Center of Fujian, Fuzhou, China.
⁶ Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China; Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China. Electronic address: ywhong@iue.ac.cn.

PMID: 36395845
DOI: 10.1016/j.scitotenv.2022.160210

Abstract

Formaldehyde (HCHO) is a vital reactive carbonyl compound, which plays an important role in the photochemical process and atmospheric oxidation capacity. However, the current studies on the quantification of HCHO impacts on atmospheric photochemistry in southeast coastal areas of China with an obvious upward trend of ozone remain scarce and unclear, thus limiting the full understanding of formation mechanism and control strategy of photochemical pollution. Here, systematic field campaigns were conducted at a typical coastal urban site with good air quality to reveal HCHO mechanism and effects on O₃ pollution mechanism during spring and autumn, when photochemical pollution events still frequently appeared. Positive Matrix Factorization model results showed that secondary photochemical formation made the largest contributions to HCHO (69 %) in this study. Based on the photochemical model, the HCHO loss rates in autumn were significantly higher than those in spring (P < 0.05), indicating that strong photochemical conditions constrain high HCHO levels in certain situations. HCHO mechanism increased the ROx concentrations by 36 %, and increased net O₃ production rates by 31 %, manifesting that the reduction of HCHO and its precursors' emissions would effectively mitigate O₃ pollution. Therefore, the pollution characteristics and photochemical effects of HCHO provided significant guidance for future photochemical pollution control in relatively clean areas.

Keywords: Atmospheric oxidation capacity; Formation mechanism; HCHO; Photochemical effects; Radical chemistry.

MeSH terms

Air Pollutants* / analysis
China
Cities
Environmental Monitoring
Ozone* / analysis
Photochemical Processes

Substances

Air Pollutants
Ozone