An analysis of the correlation between SARS cases from April 28th
2003 to May 24th
2003 and air pollution index in Beijing divided into three phases is carried out with approach of mathematical statistics. The study discovers a very high correlation between inhalable particulates and SARS cases, and SARS cases in Beijing show the best correlation with the air pollution index on the confirmed 4th
previous day. It is not clear the mechanism that supports the phenomena. Suggestions for further study are put forward.