Study on physical and chemical characteristics and source of atmospheric Single particulate matter in Rizhao city based on EPAS technology

The physical and chemical characteristics of atmospheric aerosol particles are complex in urban areas. It is of great significance to clarify the influence of different emission sources on atmospheric chemical components for tracing and fine control of air pollution. In this study, passive aerosol samplers were used to collect samples in urban area and steel industrial area in Rizhao, a typical coastal city in eastern China, the collected samples were analyzed by intelligent scanning electron microscope environmental particle analysis system (IntelliSEM-EPAS), which is based on computer-controlled scanning electron microscopy technology. The results show that the atmospheric particulates in Rizhao city are mainly composed of irregular carbonaceous particles, sulfur-containing particles and mineral particles, the number contribution of C-rich particles in urban samples is 53.5%, which is 2.5 times higher than that in steel industrial area samples, the number contribution of particles greater than 1 μm was 9.0%, which is 1.7 times that of the samples in steel industrial area, urban dwellers' activities and industrial processes are the main sources of atmospheric particulate matter in urban area. In steel industrial area, the number contribution of sulfur-containing particles is 72.9%, the mass contribution of sulfur-containing particles is 30.9%, and the mass contribution of iron rich particles is 5.3%, which are 1.8 times, 3.6 times and 2.9 times higher than that of urban samples, respectively. These results indicated that primary pollutants emitted by iron and steel enterprises and secondary formation are the main sources of atmospheric particles in steel industrial area, which has a significant impact on the composition of regional atmospheric particulates.