Analysis on the contribution rates of point and area source emissions to wuhan SO2, NO2, PM2.5 concentrations and atmospheric environmental capacity

Abstract

Knowing the contribution rates and sharing rate of local source emissions to the atmospheric environmental capacity (AEC) is of great significance to the formulation of regional air pollution source control measures. Based on WRF-CALPUFF coupling models and the second pollution source survey data, Wuhan was taken as the research area, and the contribution rates of point and area source emissions to the SO2, NO2 and PM2.5 concentration in national pollutant control points (abbreviated as "national control points"), the AEC and its source emission sharing rate of each region were calculated. The results showed that WRF-CALPUFF had better reproducibility, the contribution rates of different pollution source emissions to the SO2, NO2 and PM2.5 concentration in national control points had obvious spatial distribution characteristics, and the contribution rates of key point sources to the SO2 concentration of each national control point exceeded 40%, while the contribution rates of the main urban area source to the NO2 and PM2.5 concentrations exceed 60%; the AEC of SO2, NO2 and PM2.5 in different regions had obvious seasonal and spatial changes, and the source emissions of NO2 and PM2.5 in the main urban area were 8.7 times and 3 times of its AEC, respectively. The calculation results from source sharing rate of regional AEC showed that the AEC of SO2 was mainly shared by point sources, and the AEC of NO2 and PM2.5 was mainly shared by area sources, but the sharing rate of SO2, NO2 and PM2.5 AEC from different regional source emissions showed different characteristics. The analysis of air quality improvement during the 7th Military World Games in 2019 and the COVID-19 pandemic in 2020 shows that the calculation formula about regional source sharing rate of AEC proposed in this paper is reasonable and the implementation of refined control to regional source emissions with the source sharing rate of regional AEC plays an important role on the continued improvement of Wuhan air quality.