Study on the distribution characteristics of air particle concentration in urban agglomeration in China

Based on the monitoring data of particulate matter (PM_2.5 and PM₁₀) from 2015 to 2022, the concentration distribution characteristics and similarities and differences of particulate matter in 10 urban agglomerations (169 cities) in China were analyzed from the perspectives of daily average concentration, annual average concentration, compliance from a probability theory angle, and the required concentration reduction for compliance. The results indicated that the pollution levels of particulate matter within urban agglomerations in China tend to stabilize, while significant differences existed among different urban agglomerations. The concentration of particulate matter within urban agglomerations in China exhibited a stratified pattern. Based on the concentration levels, the 10 urban agglomerations were categorized into three groups: high, medium, and low concentrations. This classification remained consistent when viewed from a statistical distribution perspective, except for the Guanzhong Plain urban agglomeration, which was classified as a high-concentration urban agglomeration. The differences in the required concentration reduction for compliance (secondary standard of Ambient Air Quality Standard (GB 3095-2012)) were significant among urban agglomerations. The PM_2.5 and PM₁₀ levels in the Western Taiwan Strait urban agglomerations and the PM₁₀ levels in the Pearl River Delta urban agglomeration have already met the standards. However, in order for the Central Plains, Guanzhong Plain, Beijing-Tianjin-Hebei, and Shandong Peninsula urban agglomerations to meet the standards, the concentration of PM_2.5 and PM₁₀ needed to be reduced by more than 50% and 27%, respectively. It was recommended to scientifically establish regional stage target values for particulate matter in line with China's national conditions, to accelerate compliance in urban agglomerations in stages based on their own conditions.s.