Analysis of typical heavy pollution episode in winter in Shijiazhuang City

To investigate the formation and the key affecting elements of the heavy pollution episode in Shijiazhuang City,typical heavy pollution episode during January 7th-10 th,2015is analyzed in the aspects of the variation of PM2.5concentration,the evolution of metrological conditions and its effects on PM2.5concentration,the correlation between PM2.5and major gaseous pollutants,and transboundary transport of pollutants.The result shows that the heavy pollution episode is formed under stable metrological conditions of North China,and surface pressure and wind field have great influence on PM2.5concentration.The high correlation between concentrations of NO2 and PM2.5shows the aggravation of traffic-related air pollution.The high correlation between concentrations of SO2 and PM2.5indicates that coal combustion is still the important pollution source in Shijiazhuang City.During the episode,the pollutants transported from city to city in South Hebei Province.