Understanding the spatial representativeness of air quality monitoring network and its application to PM2.5 in the mainland China

Air pollution has seriously endangered human health and the natural ecosystem during the last decades.Air quality monitoring stations(AQMS)have played a critical role in providing valuable data sets for recording regional air pollutants.The spatial representativeness of AQMS is a critical parameter when choosing the location of stations and assessing effects on the population to long-term exposure to air pol-lution.In this paper,we proposed a methodological framework for assessing the spatial representative-ness of the regional air quality monitoring network and applied it to ground-based PM2.5 observation in the mainland of China.Weighted multidimensional Euclidean distance between each pixel and the sta-tions was used to determine the representativeness of the existing monitoring network.In addition,the K-means clustering method was adopted to improve the spatial representativeness of the existing AQMS.The results showed that there were obvious differences among the representative area of 1820 stations in the mainland of China.The monitoring stations could well represent the PM2.5 spatial distri-bution of the entire region,and the effectively represented area(i.e.the area where the Euclidean dis-tance between the pixels and the stations was lower than the average value)accounted for 67.32％of the total area and covered 93.12％of the population.Forty additional stations were identified in the Northwest,North China,and Northeast regions,which could improve the spatial representativeness by 14.31％.