Identification of ozone sensitivity for NO2 and secondary HCHO based on MAX-DOAS measurements in northeast China

Jiexiao Xue; Ting Zhao; Yifu Luo; Congke Miao; Pinjie Su; Feng Liu; Guohui Zhang; Sida Qin; Youtao Song; Naishun Bu; Chengzhi Xing

doi:10.1016/j.envint.2021.107048

Identification of ozone sensitivity for NO₂ and secondary HCHO based on MAX-DOAS measurements in northeast China

Environ Int. 2022 Feb:160:107048. doi: 10.1016/j.envint.2021.107048. Epub 2021 Dec 24.

Authors

Jiexiao Xue¹, Ting Zhao¹, Yifu Luo¹, Congke Miao¹, Pinjie Su¹, Feng Liu¹, Guohui Zhang¹, Sida Qin², Youtao Song¹, Naishun Bu³, Chengzhi Xing⁴

Affiliations

¹ School of Environmental Science, Liaoning University, Shenyang 110036, China.
² Liaoning Science and Technology Center for Ecological and Environmental Protection, Shenyang 110161, China.
³ School of Environmental Science, Liaoning University, Shenyang 110036, China; Key Laboratory of Wetland Ecology and Environment Research in Cold Regions of Heilongjiang Province, Harbin University, 150086, China. Electronic address: bunaishun@lnu.edu.cn.
⁴ Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China. Electronic address: xingcz@aiofm.ac.cn.

PMID: 34959197
DOI: 10.1016/j.envint.2021.107048

Abstract

In this study, tropospheric formaldehyde (HCHO) vertical column densities (VCDs) were measured using multi-axis differential optical absorption spectroscopy (MAX-DOAS) from January to November 2019 in Shenyang, Northeast China. The maximum HCHO VCD value appeared in the summer (1.74 × 10¹⁶ molec/cm²), due to increased photo-oxidation of volatile organic compounds (VOCs). HCHO concentrations increased from 08:00 and peaked near 13:00, which was mainly attributed to the increased release of isoprene from plants and enhanced photolysis at noon. The HCHO VCDs observed by MAX-DOAS and OMI have a good correlation coefficient (R) of 0.78, and the contributions from primary and secondary HCHO sources were distinguished by the multi-linear regression model. The anthropogenic emissions showed unobvious seasonal variations, and the primary HCHO was relatively stable in Shenyang. Secondary HCHO contributed 82.62%, 83.90%, 78.90%, and 41.53% to the total measured ambient HCHO during the winter, spring, summer, and autumn, respectively. We also found a good correlation (R = 0.78) between enhanced vegetation index (EVI) and HCHO VCDs, indicating that the oxidation of biogenic volatile organic compounds (BVOCs) was the main source of HCHO. The ratio of secondary HCHO to nitrogen dioxide (NO₂) was used as the tracer to analyze O₃-NO_x-VOC sensitivities. We found that the VOC-limited, VOC-NO_x-limited, and NO_x-limited regimes made up 93.67%, 6.23%, 0.11% of the overall measurements, respectively. In addition, summertime ozone (O₃) sensitivity changed from VOC-limited in the morning to VOC-NO_x-limited in the afternoon. Therefore, this study offers information on HCHO sources and corresponding O₃ production sensitivities to support strategic management decisions.

Keywords: Formaldehyde; HCHO/NO(2); MAX-DOAS; Ozone production sensitivity; Secondary source.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Air Pollutants* / analysis
China
Environmental Monitoring / methods
Nitrogen Dioxide / analysis
Ozone* / analysis
Spectrum Analysis
Volatile Organic Compounds* / analysis

Substances

Air Pollutants
Volatile Organic Compounds
Ozone
Nitrogen Dioxide