Diurnal, weekly and monthly spatial variations of air pollutants and air quality of Beijing

Under the National Ambient Air Quality Standard released in 2012 (NAAQS-2012), Beijing began to publicize hourly Air Quality Index as well as real time concentrations of 6 pollutants in its web platform to provide detailed information for air quality assessment from 2013. In this study, hourly air quality monitoring data from May 2014 to April 2015 were collected for all 35 monitoring stations in Beijing to analyze the temporal and spatial variations of air pollutants and air quality. It is found that in spatial pattern, the air qualities in southern and northern Beijing are totally different. The association between heavy pollution concentrations and wind situations suggested that neighboring area's air quality has an important role in the air quality of Beijing combining with air quality attainment rates in all 35 monitoring stations and northern China. For temporal variations, late night and early morning are the most polluted time while afternoon is the least polluted time for all pollutants except O-3 with most polluted time in afternoon. Summer time in Beijing has the best air quality while winter time has the worst air quality coinciding with the heating season in the winter. (C) 2015 Elsevier Ltd. All rights reserved.