Eighteen polycyclic aromatic hydrocarbons(PAHs)in PM2.5 collected near the NanjingOlympic Sport Center across the Asian Youth Games(AYG)period(from August 2 to August 28,2013)were analyzed using GC-MS.Their levels,sources and health risks to human are discussed.Results showed that the total concentrations of PAHs in PM2.5 were 9.43,7.21 and 8.83 ng m-3 forpre-(August 3-15),during-(August 16-24)and post-(August 25-28)AYG periods,respectively.They were dominated by 5-ring and 6-ring PAHs.Total PAHs concentration during AYG periodin PM2.5 decreased by 24%,when compared with those for pre-AYG period.Forcombustion-derived PAHs and carcinogenic PAHs,they decreased by 26%and 21%,respectively.It implied that the pollution control measures implemented during the AYG can effectively reducethe emission of PAHs from various sources.The poor correlations between PAHs andmeteorological parameters also favored that the variations of PAHs are raised by the changes ofemission sources.Diagnostic ratios and principal component analysis revealed that vehicleemission and coal combustion were the predominant contributors,with minimal effects frombiomass burning and petroleum.The health risks for human exposed to PAHs in PM2.5 werequantitatively assessed by BaP equivalent concentration(BaPeq)and the incremental lifetimecancer risk(ILCR).The estimated ILCR for PAHs during the AYG periods decreased by 0.28 and1.39 per 1,000,000 exposed children and adults than those for the the pre-AYG,respectively.Itindicateed that the pollution control measures reduced the risks of PAHs to sportsmen or humangathered around the Olympic Sport Center.