Method of Identifying Air Pollution from Iron and Steel Industry Based on Ambient Air Quality Monitoring Data Analysis

An air quality monitoring network with high temporal and spatial resolution has been established in Beijing-Tianjin-Hebei (BTH) and the surrounding area. However, those data are mainly used for ambient air quality assessment and are rarely applied for identifying air pollution sources. In this study, a data analysis method referring to the characteristic radar chart (CRC) was used to analyze air pollution characteristics in BTH and the surrounding area based on air monitoring data, including SO2, NO2, CO, PM2.5, and coarse particulate matter (PM10 minus PM2.5) mass concentration. Eight pollution characteristics were identified, which included characteristics dominated by SO2, NO2, CO, PM2.5, or coarse particulate matter and characteristics co-dominated by SO2-CO, NO2-CO, or PM2.5-CO. As an example, to illustrate the major cause of the pollution characteristic co-dominated by SO2-CO, we combined the analysis of the spatio-temporal distribution pattern of this pollution characteristic, emission intensity of major pollution sources, and PM2.5 source apportionment. The results showed that the percentage of days with the pollution characteristic co-dominated by SO2-CO in the study region and period was 7.6%. ① The occurrence frequency of the pollution characteristic co-dominated by SO2-CO in the non-heating season was 11.5% higher than that in the heating season. This pattern mainly existed in cities where the iron and steel industry were densely located, e.g., in Tangshan, Anyang, and Changzhi. ② Furthermore, the iron and steel industry had higher SO2 and CO emission intensity, which were 1.3 times and 4.0 times the average intensity of major sectors, including coal-fired power plants, vehicular exhaust, residential coal combustion, etc. in BTH and the surrounding area. ③ According to PM2.5 source apportionment, the contributions of the iron and steel industry to PM2.5 when the pollution characteristic was co-dominated by SO2-CO were 48.6%, 36.9%, and 40.2% in Tangshan, Anyang, and Changzhi, respectively. In the other period, PM2.5 was mainly from coal-burning or fugitive dust emissions. ④ The pollution characteristic co-dominated by SO2-CO and the tracer elements of the iron and steel industry changed simultaneously during the pollution episode in east Tangshan. In summary, the pollution characteristic co-dominated by SO2-CO can indicate the impact of iron and steel industry emissions on air quality. This method expands the application of air quality monitoring data and provides a new tool for the instant identification of iron and steel industry pollution. © 2022, Science Press. All right reserved.