A WRF-CMAQ modeling of atmospheric peroxyacetyl nitrate and source apportionment in Central China

Yifei Wang; Mei Sun; Xueqi Qiao; Xiaoxiao Feng; Xiaole Zhang; Jing Wang; Jianbo Zhang

doi:10.1016/j.scitotenv.2023.165033

A WRF-CMAQ modeling of atmospheric peroxyacetyl nitrate and source apportionment in Central China

Sci Total Environ. 2023 Oct 15:895:165033. doi: 10.1016/j.scitotenv.2023.165033. Epub 2023 Jun 22.

Authors

Yifei Wang¹, Mei Sun², Xueqi Qiao¹, Xiaoxiao Feng³, Xiaole Zhang³, Jing Wang⁴, Jianbo Zhang⁵

Affiliations

¹ State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
² State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; Beijing Ecological Environment Assessment and Complaints Center, Beijing 100161, China.
³ Institute of Environmental Engineering, ETH Zürich, Zürich 8093, Switzerland; Laboratory for Advanced Analytical Technologies, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf 8600, Switzerland.
⁴ Institute of Environmental Engineering, ETH Zürich, Zürich 8093, Switzerland; Laboratory for Advanced Analytical Technologies, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf 8600, Switzerland. Electronic address: jing.wang@ifu.baug.ethz.ch.
⁵ State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China. Electronic address: jbzhang@pku.edu.cn.

PMID: 37355137
DOI: 10.1016/j.scitotenv.2023.165033

Abstract

Atmospheric peroxyacetyl nitrate (PAN), as an essential constituent in the photochemical smog, is formed from photochemical reactions between volatile organic compounds (VOCs) and NOx. However, limited regional studies on distribution, formation and sources of PAN restrict the further understanding of the atmospheric behavior and environmental significance of PAN. In this study, the variation characteristics of PAN and the influencing factors to PAN concentrations were investigated using the WRF-CMAQ model simulation in the central China during July 2019. The results showed that the monthly mean concentration of PAN in the near-surface layer was 0.4 ppbv and increased with the height rising, accompanied by strong intra-day variation. The process analysis suggested that the removal was mainly controlled by dry deposition (57 %), followed by the gas-phase chemistry (43 %) which was mainly attributed to the thermal decomposition. Based on the sensitivity simulation, PAN concentrations decreased effectively in most of the simulated regions when precursors of VOCs and NOx emissions were reduced, and PAN concentrations were more sensitive to VOCs emissions than NOx emissions. The reduction of NOx and VOCs could lead to enhanced atmospheric oxidation in east-central region, which in turn hindered the decrease of PAN concentrations. During the simulation period, we found that emissions from industry and transportation sectors had the greatest impact on PAN concentrations in the central China, with contributions of 39 %-49 % and 33 %-41 %, respectively.

Keywords: Peroxyacetyl nitrate; Process analysis; Sensitivity; Spatial distribution.