Inventory and Characteristics of Small-Scale PM2.5 in a District of Tianjin

Abstract Based on the activity level data of PM2.5 pollution sources in a certain area around Tianjin City, corresponding emission factors were selected to construct a 0.5km×0.5km small-scale PM2.5 emission inventory for the area in 2017. The results showed that in 2017, an area around the city of Tianjin emitted 3,509.91 tons of PM2.5. According to the emission inventory of PM2.5, in terms of the emission categories of pollution sources, the emission proportion of dust sources, process sources, road mobile sources and fixed combustion sources is 48%, 38%, 6% and 5% respectively. From the perspective of pollution sources, steel emissions accounted for 35% of the overall PM2.5 emissions, and road dust emissions accounted for 25.4% of the overall emissions. In addition, spatial distribution results show that there are pollution sources such as 1 boiler, scattered coal, some enterprises, several main roads, several construction sites and a large number of restaurants within a 3-kilometer radius of a monitoring station in a district around the city of Tianjin. The PM2.5 emitted by these pollution sources will directly affect the PM2.5 concentration in the district. There are still some uncertainties in this list, so the data of activity level, such as road traffic flow, need to be further detailed, and the localization study of emission factors should be further carried out, so as to provide a scientific basis for the formulation of regional pollution prevention strategies.