Spatiotemporal variations of air pollution and population exposure in Shandong Province, eastern China, 2014-2018.

Abstract

To clarify the characteristics and interannual variation of air pollution since the implementation of China's clean air actions, hourly in situ measurements of six gaseous and particulate criteria pollutants at 100 sites in Shandong Province were studied during 2014-2018. General decreasing trends in the concentrations of PM2.5, PM10, NO2, SO2, and CO were observed, while O3 increased continuously. In 2018, the annual average PM2.5, PM10, NO2, SO2, and CO concentration in Shandong was 50, 100, 35, 16μgm-3, and 1.5mgm-3, representing decreases of 39%, 30%, 24%, 73%, and 35% from 2014, respectively. These decreases occurred throughout the province. Seven "2 + 26" cities (in Beijing-Tianjin-Hebei and its surrounds) in western Shandong had higher average concentrations and greater reductions than other areas. In contrast, O3 concentration rose, with occurrences of the 90th percentile of all daily maximum 8-h averages increasing by 12% from 159 to 181μgm-3, during 2014-2018. From May to September, O3 pollution dominated as the sole primary pollutant on non-attainment days, and PM2.5 contributed to more than 90% of polluted days in wintertime months. Population exposures were investigated based on high-resolution monitoring data and population distribution, and high exposure to pollution was displayed. The population-weighted exposure to PM2.5 in Shandong was 50μgm-3, a decrease of 33%. Eighty-nine percentage of the provincial population was exposed to PM2.5 > 35μgm-3, while for 99.2% of population in the seven "2 + 26" cities, PM2.5 exposure exceeded 50μgm-3.