Indoor/Outdoor Characterization And Sources Of PM_2.5-bound PAHs,NPAHs And OPAHs In Jinan,China

People spend 80%of their time indoors,therefore,the indoor air quality is particularly important to human health.Polycyclic aromatic hydrocarbons(PAHs)are teratogenic,carcinogenic,and mutagenic.Thus,they are harmful to the human.The concentration of their derivatives(NPAHs and OPAHs)are one or two orders of magnitude lower than PAHs,but they are more carcinogenic and teratogenic than PAHs.In order to study the pollution characteristics of indoor/outdoor PM2.5-bound PAHs,NPAHs and OPAHs in urban and suburban hotels in Jinan,indoor/outdoor PM2.5 samples were collected simultaneously at both urban and suburban hotels in Jinan in January 2016.18 PAHs,16 NPAHs,and 5 OPAHs were analyzed by using gas chromatography-mass spectrometry(GC/MS-MS).The indoor/outdoor concentration,indoor and outdoor relationships,source,and carcinogenic risk of PM2.5-bound PAHs,NPAHs,and OPAHs were studied in urban and suburban of Jinan.Based on the experimental data,the indoor and outdoor concentrations of PM2.5-bound PAHs,NPAHs,and OPAHs in urban and suburban hotels were obtained.The concentrations of PM2.5-bound PAHs,NPAHs,and OPAHs in urban areas were higher than suburban;the concentrations of outdoor PM2.5-bound PAHs,NPAHs,and OPAHs were higher than indoor,except urban hotel2.There was no significant difference in the composition of PAHs and their derivatives in this study area.4-ring PAHs(such as Flt,PYR,BaA,Chr)were predominated at PAHs;9N-ANT and 2+3N-FLA were the dominant NPAHs;and 9-FO was the most abundant OPAHs at all sites.Through indoor/outdoor concentration comparison(I/O)of PM2.5-bound PAHs and their derivatives,we found that the I/O of PAHs,NPAHs,and OPAHs in urban hotels1 and suburban hotel were less than 1,indicating that they mainly come from outdoor sources;in urban hotel2,the I/O of 2-3 ring PAHs,2-3 ring NPAHs(except 3N-BYL and 9N-ANT)and OPAHs were greater than 1,which are mainly from indoor sources.Principal component analysis(PCA)and characteristic ratio method were used to analyze the source of PM2.5-bound PAHs,NPAHs and OPAHs in this study area.The results shown that the main sources of PM2.5-bound PAHs in this study area were solid fuel combustion and motor vehicle exhaust(mainly gasoline vehicle exhaust);the main sources of NPAHs and OPAHs were solid fuel combustion,motor vehicle exhaust and secondary generation.We also found that the secondary generation pathways of NPAHs in this study area was caused by OH·.The assessment of the cancer risk of human health exposure to PM2.5-bound PAHs and NPAHs in hotels indoor and outdoor of urban and suburban in Jinan was performed by calculating the incremental lifetime cancer risk(ILCR).It was found that when human exposed to urban outdoor have highest cancer risk.The ILCR values in urban air environment were higher than suburban;and in outdoor environment were higher than indoor.The ILCR value of PM2.5-bound PAHs in the indoor atmosphere decreased as the distance from the traffic source increases.However,the ILCR values of PM2.5-bound NPAHs in urban hotel2 were higher than other hotels,which may be due to its obvious kitchen cooking activities.