STUDY ON THE SPATIAL DISTRIBUTION UNIFORMITY OF PM2. 5 IN TYPICAL CITIES IN CHINA

With the implementation of the new air quality standards，measurements of PM2. 5 have been carried out in 74 cities since 2013． In this paper，the spatial distribution of atmospheric PM2. 5 in typical cities of different regions was analyzed． The relative standard deviation ( ＲSD) of PM2. 5 daily average concentration in these cities ranged from 13% to 26%，with average ＲSD of 18%; the spatial distribution of PM2. 5 in southern cities was more uniform than in northern cities; specifically，the spatial distribution of PM2. 5 in northern cities in winter and spring was less uniform than in summer and autumn，while in southern cities the spatial distribution was the least uniform in summer among all seasons; In terms of uniformity，the spatial distribution of PM2. 5 is similar to that of PM10 ，but better than gaseous pollutants． The comprehensive analysis shows that the representative of the PM2. 5 monitoring points in the current national monitoring network in China can meet the requirement of air quality monitoring and assessment in urban areas