Financial support from the National Natural Science Foundation of China (Grant No. 40475049) ; the Natural Sciences Foundation of Beijing city (Grant No. 8032012) are acknowledged.
A total of 11 PM2.5 samples were collected from October 2003 to October 2004 at 8 sampling sites in Beijing city. The PM2.5 concentrations are all above the PM2.5 pollution standard (65 μg m^-3) established by Envi...