北京市高海拔地区百花山空气质量状况及与市区的差异性研究

Air Quality in High-altitude Baihua Mountain Area and Its Different Characteristics from Urban Area in Beijing

对北京市远郊百花山(海拔1300 m)2007—2017年大气常规6项污染物数据进行了分析,并与代表市区的国控站点均值数据进行了比较。研究发现,百花山SO2、CO、PM2.5浓度为国控站点浓度的35.5%~35.7%,NO2、PM 10、O 3浓度分别为国控站点浓度的14.0%、41.5%、185.5%。11年间,百花山6项常规污染物浓度逐年降低。2013—2017年,百花山PM2.5浓度年均降速为11.4%,低于国控站点13.3%的年均改善水平。百花山和国控站点在污染物季节变化趋势上基本一致,秋季颗粒物浓度差异最大,春季差异最小。百花山6项污染物的日变化峰谷比值为1.21~1.44,其差异小于国控站点。各项污染物浓度在18:00出现峰值,认为主要受城区远距离传输影响。2013—2017年,百花山共出现5个PM2.5重污染天,5级以上重污染小时数为442 h,国控站点有2%的重污染小时与百花山同步。

This study analyzed the concentrations of the six regularly monitored air pollutants in Baihua Mountain of Beijing,which is 1300 m above sea level,froM2007 tO2017.Meanwhile,the differences in long-term variation in air quality between Baihua Mountain and the state-control stations in urban area were studied.The results showed that all concentrations of SO2,CO,and PM2.5 at Baihua Mountain were 35.5%to 35.7%of the values at the state-control sites.The NO2,PM 10,and ozone concentrations were 14.0%,41.5%,and 185.5%of the values at the state control sites,respectively.All concentrations of the six pollutants at Baihua Mountain declined gradually during the 11 years.The decreasing rate of PM2.5 concentration at Baihua Mountain froM2013 and 2017 was 11.4%per year,which was slower than the rate of 13.3%per year at the state-control sites.Although PM2.5 concentrations at Baihua Mountain and state-control stations showed a similar seasonal variation,the largest difference occurred in autumn,whereas the smallest difference was found in spring.Strong diurnal variation in PM2.5 concentration was also observed at Baihua Mountain with the ratio of maximum and minimum ranging from 1.21 to 1.44,which was smaller than that in urban area.Concentrations of all pollutants reached their peaks at 18:00 pm,suggesting the effect of the long-distance transport form urban area.Five heavily PM2.5 polluted days and 442 heavily polluted hours were observed at Baihua Mountain froM2007 tO2017,with 2%of them synchronous with those at the state-control sites.