Abstract： Online monitoring data of fine particulate matter PM_2.5 and inhalable particulate matter PM₁₀ were collected at six monitoring points in Nanjing from September 2014 to January 2015. The temporal and spatial distribution characteristics of atmospheric particulate matter and their relationship with meteorological factors were analyzed. The results show that the average daily mass concentrations of PM_2.5 and PM₁₀ are 70 and 150 μg/m³, and the excessive rates are 37.91% and 30.72%, respectively. The fraction of mass concentration of PM_2.5 in mass concentration of PM₁₀reaches 63.6%， and the correlation coefficient is as great as 0.90. The mass concentrations of particulate matter are greater in winter than those in autumn. The mass concentrations daily change of PM_2.5 and PM₁₀ appears double peaks diagram， peaking at about 10:00 and 22:00. The temperature shows a negative correlation with mass concentrations of PM_2.5 and PM₁₀, which is more significant on mass concentration of PM₁₀ （significant test level p<0.01）, but shows a positive correlation with mass concentration ratio of PM_2.5 and PM₁₀. The precipitation can effectively reduce mass concentrations of PM_2.5 and PM₁₀, and has an obvious effect on coarse form. The relative humidity shows a negative correlation with the mass concentration of PM₁₀. The mass concentration of PM_2.5 increases first and then decreases with the increase of relative humidity, peaking when the relative humidity is between 70% and 80% . The wind force shows a significant negative correlation with mass concentrations of PM_2.5 and PM₁₀. The mass concentration of PM_2.5 is at a lower level in directions of northwest wind and west-northwest wind.

Keywords: atmospheric particulate matter; fine particulate matter PM_2.5; inhalable particulate matter PM₁₀; pollution condition; meteorological factor