Abstract: ObjectiveTo investigate the pollution characteristics of polycyclica romatic hydrocarbons(PAHs),organic carbon(OC)and element carbon(EC)in PM_2.5 and PM₁₀.MethodsThe PM_2.5 and PM₁₀ samples collected from June 16 to 18 and from June 20 to 22 of 2006 in Beijing were measured and 17 kinds of polycyclica romatic hydrocarbons,organic carbon and element carbon were analyzed.ResultsThe average mass concentrations of PAHs in PM2.5 and PM₁₀ we re 0.011-2.846 ng/m³ and 0.013-4.415 ng/m³,respectively.The average mass concentrations of OC and EC were 28.56 μg/m³,8.75μg/m³ and 41.14μg/m³,15.43μg/m³ in PM_2.5 and PM₁₀,respectively.ConclusionIn PM_2.5 and PM₁₀,4 to 5 rings PAHs we re the main components of 17 kinds of PAHs,and the total concentration of OC and EC accounted for the similar percentage.Carbon was one of the main components of PM_2.5 and PM₁₀ in the air sample in Beijing.