Chemical Characterization and Source Apportionment of PM2.5 during Spring and Winter in the Yangtze River Delta, China

Wenjiao Du; Yanru Zhang; Yanting Chen; Lingling Xu; Jinsheng Chen; Junjun Deng; Youwei Hong; Hang Xiao

doi:10.4209/aaqr.2017.03.0108

Chemical Characterization and Source Apportionment of PM2.5 during Spring and Winter in the Yangtze River Delta, China

Wenjiao Du¹^,2^,3, Yanru Zhang¹^,2^,3, Yanting Chen¹^,2, Lingling Xu ¹^,2, Jinsheng Chen ¹^,2, Junjun Deng¹^,2, Youwei Hong¹^,2, Hang Xiao¹^,2

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¹Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
²Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
³University of Chinese Academy of Sciences, Beijing 100086, China

Received: June 26, 2017
Revised: June 21, 2017
Accepted: June 21, 2017
Download Citation: ||https://doi.org/10.4209/aaqr.2017.03.0108

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Cite this article:
Du, W., Zhang, Y., Chen, Y., Xu, L., Chen, J., Deng, J., Hong, Y. and Xiao, H. (2017). Chemical Characterization and Source Apportionment of PM2.5 during Spring and Winter in the Yangtze River Delta, China. Aerosol Air Qual. Res. 17: 2165-2180. https://doi.org/10.4209/aaqr.2017.03.0108

HIGHLIGHTS

The sources of PM_2.5 in main cities and background site in the YRD were studied.
The effect of long-distance transport of dust storm in Northern China was proved.
The dominancy of biomass burning via air mass from Southwestern China was analysed.
Local emission and long-range transport were proposed to mitigate haze in the YRD.

ABSTRACT

To investigate the characteristics and sources of PM_2.5 in the Yangtze River Delta (YRD) region, a total of 10 sampling sites were selected in the three major cities of Shanghai, Nanjing, and Ningbo and the regional background city of Lin’an, and 380 samples were collected in spring and winter. The spatiotemporal characteristics of the PM_2.5 mass concentration and the chemical components were analyzed. Meanwhile, air mass clusters and the positive matrix factorization (PMF) source apportion model were comprehensively used to identify the sources of PM_2.5. The mass concentration of PM_2.5 in winter (83.51–107.64 µg m^–3) was higher than that in spring (54.11–85.72 µg m^–3). Sulfate, nitrate, and ammonium (SNA) dominated the PM_2.5, accounting for 39.0% in spring and 46.1% in winter in the YRD region. Higher ratio of secondary organic carbon (SOC) to organic carbon (OC) generally occurred in winter due to increased emissions of organic precursors. The mean equivalent ratio of AE/CE was 0.81 ± 0.25 in winter and 0.96 ± 0.33 in spring, which indicated a slight alkalinity of the atmospheric particles in the YRD region. Secondary aerosols (29.44%) and traffic (25.66%) were identified as the main sources of PM_2.5 in the YRD during spring, and they contributed 22.71% and 29.71% in winter. In addition, air mass flow from Northern China imported substantial fugitive soils to the YRD region in spring and enhanced the contribution of combustion in winter through long-range transport, while air masses originating from Southwestern China were strongly associated with biomass burning. Our results showed that the PM_2.5 concentration and chemical characterization in the YRD region was significantly influenced by air mass transport.

Keywords: Source apportionment; PM2.5; Yangtze River Delta; Chemical components; Air mass cluster