A continuous air quality observation was conducted in the urban area of Shanghai from April 28 to May 18 in 2011. The mass concentration of particle matters and main chemical compositions of fine particle were measured and analyzed. The mass concentrations of PM10and PM2. 5during the dust episode were much higher than those in non-dust episode,with the maximum daily mass concentrations of PM10and PM2. 5reaching 787. 2 μg·m- 3and 139. 5 μg·m- 3,respectively. The average PM2. 5/ PM10ratio was( 32. 9 ±14. 6) %...