Chemical composition and size distribution of airborne particulate matters in Beijing during the 2008 Olympics

► The concentrations of atmospheric particulate matters, water-soluble ions, trace elements, EC and OC were studied. ► The size distributions of those compounds were discussed. ► The correlations between Sulfate and Ammonium, Sulfate and Nitrate were studied to research the source of those secondary inorganic ions. ► The ratios and correlation of OC and EC were discussed to research the source of carbonaceous. ► The effects of pollution control measures on air pollution were discussed.