Quantifying the impacts of inter-city transport on air quality in the Yangtze River Delta urban agglomeration, China: Implications for regional cooperative controls of PM2.5 and O3

Kangjia Gong; Lin Li; Jingyi Li; Momei Qin; Xueying Wang; Qi Ying; Hong Liao; Song Guo; Min Hu; Yuanhang Zhang; Jianlin Hu

doi:10.1016/j.scitotenv.2021.146619

Quantifying the impacts of inter-city transport on air quality in the Yangtze River Delta urban agglomeration, China: Implications for regional cooperative controls of PM_2.5 and O₃

Sci Total Environ. 2021 Jul 20:779:146619. doi: 10.1016/j.scitotenv.2021.146619. Epub 2021 Mar 19.

Authors

Kangjia Gong¹, Lin Li¹, Jingyi Li¹, Momei Qin¹, Xueying Wang¹, Qi Ying², Hong Liao¹, Song Guo³, Min Hu³, Yuanhang Zhang⁴, Jianlin Hu⁵

Affiliations

¹ Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science & Technology, Nanjing 210044, China.
² Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843, USA.
³ State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
⁴ State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; CAS Center for Excellence in Regional Atmospheric Environment, Chinese Academy of Science, Xiamen 361021, China.
⁵ Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science & Technology, Nanjing 210044, China. Electronic address: jianlinhu@nuist.edu.cn.

PMID: 34030281
DOI: 10.1016/j.scitotenv.2021.146619

Abstract

The Yangtze River Delta (YRD) urban agglomeration is one of the most developed regions in China. During recent decades, this region has experienced severe regional haze and photochemical smog pollution problems. In this study, we used a source-oriented chemical transport model to quantitatively estimate the effects of inter-city transport on fine particulate matter (PM_2.5) and ozone (O₃) among the 41 cities in the YRD urban agglomeration during the EXPLORE-YRD (EXPeriment on the eLucidation of the atmospheric Oxidation capacity and aerosol foRmation, and their Effects in the Yangtze River Delta) campaign (May 17 to June 17, 2018). The results show that inter-city transport is very significant in the YRD region. On average, the emissions from the local city, the other YRD cities, and the regions outside of the YRD contribute 25.3%, 49.9%, and 24.8% to the PM_2.5, respectively, and they contribute 33.7%, 46.8%, and 19.5% of the non-background O₃, respectively. On PM_2.5 or O₃ pollution days, the transport contribution from the non-local YRD cities becomes much more important, while the local emissions and the transport from non-YRD emissions become less important. The results also suggest that the cities within a distance of 184 km and 94 km contribute 60% of the PM_2.5 and O₃, respectively. Therefore, we recommend that regional cooperative control programs in the YRD consider emission controls over cities within these ranges. The range for primary PM_2.5 (92 km) is very different from that for secondary PM_2.5 (515 km)_. Cooperative emission controls of SO₂ and NO_x on a much larger regional scale are required to reduce the secondary PM_2.5 in the YRD.

Keywords: EXPLORE-YRD campaign; Inter-city transport; Secondary PM(2.5); Source-oriented model; Yangtze River Delta.