The impact of steel emissions on air quality and pollution control strategy in Caofeidian, North China

Pollutant emission from steel industries is an important source of air pollution in Beijing-Tianjin-Hebei region. Using WRF-FLEXPART atmospheric diffusion model, this paper simulated the pollutant diffusion processes of two steel industries from Oct. 2018 to Mar. 2019 in Caofeidian district, and then analysed the pollutant diffusion characteristics, the impacts of atmospheric circulation and local circulation on pollutants diffusion, the contribution of steel industry emissions on air quality nearby emission sources and air quality observation stations. According to the statistics, the emissions of particulate matter from Jingtang (JT)and Wenfeng (WF) steelworks are 669 and 69tonsduring the period of Oct. 2018–Mar. 2019, respectively. Under the influence of East Asian winter monsoon circulation, most of the pollutants emitted from JT and WF are diffused and transported to the Bohai Sea. The contribution of emissions from JT and WF on the concentration of particulate matter with aerodynamic diameters of less than 2.5(PM2.5) in Caofeidian is relatively small, with the daily maximums of local contribution rate on PM2.5 concentration from JT and WF reaching about 15% for both. Compared to the local contribution, the contribution rate in air quality observation stations is obviously lower, with the daily maximumsless than 2% and 5% for JT and WF respectively. It is significant that the pollutant diffusion and its contribution on air quality are affected by the large-scale atmospheric circulation and local sea-land breeze circulation, providing rational insights for policy makers to formulate control strategies.