11 Apr 2023
 | 11 Apr 2023

Quantifying the seasonal variations and regional transport of PM2.5 in the Yangtze River Delta region, China: Characteristics, sources, and health risks

Yangzhihao Zhan, Min Xie, Tijian Wang, Pulong Chen, Jun Tian, Kuanguang Zhu, Yi Luo, Runqi Zhao, Shu Li, Bingliang Zhuang, and Mengmeng Li

Abstract. Given the increasing complexity of the chemical composition of PM2.5, identifying and quantitatively assessing the contributions of pollution sources has played an important role in formulating policies to control particle pollution. This study provides a comprehensive assessment between PM2.5 chemical characteristics, sources, and health risks based on sampling data conducted over one year (March 2018 to February 2019) in Nanjing. Results show that PM2.5 exhibits a distinct variation across different seasons, which is primarily driven by emissions, meteorological conditions, and chemical conversion of gaseous pollutants. First, the chemical mass reconstruction shows that secondary inorganic aerosols (SIA, 62.5 %) and carbonaceous aerosols (21.3 %) contributed most to the PM2.5 mass. The increasing oxidation rates of SO2 and NO2 from summer to winter indicate that the secondary transformation of gaseous pollutants is strongly positively correlated with relative humidity. Second, the positive matrix factorization (PMF) method shows that identified PM2.5 sources include SIA (42.5 %), coal combustion (CC, 22.4 %), industry source (IS, 17.3 %), vehicle emission (VE, 10.7 %), fugitive dust (FD, 5.8 %) and other sources (1.3 %). The Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model and the concentration-weighted trajectory (CWT) analysis are used to further explore different spatial distributions and regional transport of sources. High emissions (10-11 μg·m−3) of SIA and CC distribute in Nanjing and central China in winter. Moderate emissions (8-9 μg·m−3) of IS and VE are potentially located in the north of Jiangsu, Anhui, and Jiangxi. The PM2.5 pollution from long-range transport is attenuated by meteorological conditions and ocean air masses. Finally, the health risk assessment indicates that the carcinogenic and non-carcinogenic risks of toxic elements (Cr, As, Ni, Mn, V, and Pb) mainly come from IS, VE, and CC, which are within the tolerance or acceptable level. Although the main source of pollution in Nanjing is SIA at present, we should pay more attention to the health burden of vehicle emissions, coal combustion, and industrial processes.

Yangzhihao Zhan et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-489', Anonymous Referee #1, 25 Apr 2023
  • RC2: 'Comment on egusphere-2023-489', Anonymous Referee #2, 27 Apr 2023

Yangzhihao Zhan et al.

Yangzhihao Zhan et al.


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Short summary
Although the main source contribution of pollution is secondary inorganic aerosols in Nanjing, health risks mainly come from industry sources and vehicle emissions. Therefore, the development of mega-cities should pay more attention to the health burden of vehicle emissions, coal combustion, and industrial processes. This study provides new insight into assessing the relationship between source apportionment and health risks and can provide valuable insight into air pollution strategies.