Impact of land-cover layout on particulate matter 2.5 in urban areas of China

Urbanization in China is closely connected with ambient particulate matter 2.5(PM_(2.5)).However,the potential for altering PM_(2.5)through the urban landscape characteristics is uncertain.In this study,we analyzed the urban PM_(2.5)pollution situation for 2014–2016 and investigated the impact of landscape factors on urban PM_(2.5)in China at the city level.All the prefecture-level cities were stratified by urban population size into small(<500,000),medium(500,000–1,000,000),and large(>1,000,000),and the other second-level administrative cities were assigned as‘other’cities.The multivariate regression model including both urban landscape factors and social-economic variables explained 70.0%,32.8%,19.2%,and 12.4%of the arithmetic mean PM_(2.5)concentration(AMC-PM_(2.5))for the other,small,medium,and large cities,respectively.With regard to the configuration of land cover,agricultural activity is a major contributor of PM_(2.5)pollution,for which the explanatory power ranged from 7.6%(for the large cities)to 64%(for the other cities).In addition,grassland aggregation also has a limited but negative effect on urban PM_(2.5)pollution,despite the negligible effect on dry deposition.Overall,these findings likely reflect the interaction between urban air quality and urbanization,and will have implications for air quality control strategies.