[Objective] To observe the PM2.5 pollution characteristics in the atmosphere in Baoshan District of Shanghai as well as to analyze some related factors.[Methods] PM2.5 concentration was monitored by membrane gravimetric method.Air samples were continuously sampled for 24 h each time thus to calculate the daily average concentration.The data were used to analyze seasonal characteristics,meanwhile,the relationship between the logarithmic transformed value of PM2.5 and climate factors(wind speed,relative humid...