Regional source contributions to fine particulate matter of less studied cities in Beijing-Tianjin-Hebei region in 2017

Located in the central area of the North China Plain, the Beijing-Tianjin-Hebei region experiences severe air pollution, especially for Hebei province with five cities among the top 10 cities with the worst air quality nationwide. However, less studies have investigated local and regional contributions to cities in Hebei in comparison to Beijing and Tianjin. In this study, a source-oriented version of the Community Multiscale Air Quality (CMAQ) model is used to quantify inter- and intra-province transport of PM2.5 in 11 cities within Hebei in 2017. PM2.5 and its components vary seasonally with high levels in winter and low levels in summer. Local contributions to total PM2.5 within cities are 23%-61%, while intra-province transport contributes 10%-30%, and inter-province transport contributes 23%-46%, with top contributors of Shandong (4%-22%), Henan (3%-15%) and Shanxi (2%-11%). The primary components in most cities are mainly from local sources (30%-80%), and the secondary components are mainly from interprovince contributions (30%-66%). Local sources have the highest contributions to total PM2.5 in Shijiazhuang (-49%), followed by Shanxi (-12%) and Xingtai (-7%). Secondary components from local and intra-province emissions are the major cause of heavy pollution events. These results suggest that both local and regional joint control measures with neighboring cities and provinces are necessary for pollution reduction in Hebei cities. (c) 2023 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of

Automated summary

Located in the Beijing-Tianjin-Hebei region, Hebei province experiences severe air pollution, with five cities among the top 10 cities with the worst air quality nationwide. This study quantifies the inter- and intra-province transport of PM2.5 in 11 cities within Hebei using a source-oriented version of the CMAQ model. The results show the contributions of local and regional sources, with local sources playing a major role in most cities while inter-province transport also being significant.