Analysis of PM_(2.5) and PM_(10) mass concentration variation characteristics in Zhengzhou

This paper analyzed reach the standard and variation trend of PM2. 5and PM10 from Zhengzhou national control sites according to continuous automatic monitoring data in 2013. The results show that the annual average mass concentrations of PM2. 5and PM10 in Zhengzhou in 2013 exceeded annual average standard of grade secondary standard limit in the new criterion.The results also shows that PM10 and PM2. 5monthly mean peaks appeared in January and October and troughs in August,and the number of days of PM2. 5exceeding the standard was larger than that of PM10 in each month. The daily average concentrations of PM10 and PM2. 5in winter were significantly higher than that in other three seasons during 2013 and presented as bimodal distribution,meanwhile their concentrations during nights were integrally higher than that during days. The diurnal variation of PM2. 5in spring,summer and autumn were single peak type. The diurnal variation of PM10 in summer and autumn were single peak type and bimodal distribution in spring. There was a significant linear relationship between PM2. 5daily mean concentration and that of PM10,at the same time the ratio( p) of PM2. 5and PM10 concentration was the highest in October.