Abstract: The air suspended particles with different sizes were sampled and 22 elements analyzed in Beijing in 2 typical seasons.It was shown that the air suspended particles may be divided into 3 categories,i.e.soil elements from earth crust,pollution elements from coal burning,industry,traffic and households,and other elements from both soil and pollution.The enrichment factors of pollution elements in air suspended particles with different sizes were calculated.It was resulted that the air suspended particles come from not only coal burning,but also from traffic and natural sources.