Characteristics And Sources Of PM_2.5-bound PAHs,NPAHs And OPAHs In Jinan In Spring

With the development of economy and society,the process of industrialization and urbanization has been rapidly advancing,energy consumption has dramatically increased,and a large number of pollutants have led to a variety of atmospheric environmental problems.Polycyclic aromatic hydrocarbons(PAHs)and their derivatives(NPAHs and OPAHs)are widely present in environmental media as persistent organic pollutants and are one of the most important atmospheric pollutants.Although the concentrations of NPAHs are one to two orders of magnitude lower than those of PAHs,NPAHs and OPAHs have stronger oncogenic and mutagenic effects than PAHs.In order to understand the pollution characteristics of polycyclic aromatic hydrocarbons(PAHs)and their derivatives(NPAHs and OPAHs)in PM2.5 during spring in Jinan.We used mid-flow instructment to collect the atmospheric PM2.5 samples from March to May 2016.The collected atmospheric PM2.5 samples were analyzed with 18 PAHs,16 NPAHs and 5 OPAHs using gas chromatography-mass spectrometry(GC/MS-MS).The concentration,source,carcinogenic risk,and long-distance transmission effects of PAHs,NPAHs,and OPAHs in PM2.5 in spring and under different weather conditions(including haze,dust,etc.)were systematically studied in spring.Based on the data obtained from the experiment,this study provides a whole knowledge on the levels and diurnal variations of PAHs,NPAHs,and OPAHs in atmospheric PM2.5 in spring of Jinan.As one of the most polluted cities in China,the concentrations of PAHs,NPAHs,and OPAHs in PM2.5 in the spring of Jinan City are 39.37 ng m-3,1.82 ng m-3 and 10.49 ng m-3,and the mean nighttime concentrations(47.91 ng m-3,2.20 ng m-3,12.36 ng m-3)are higher than that of the daytime average concentration(32.54 ng m-3、1.52 ng m-3 和8.98ng m-3).This study also found that the highest concentrations of PAHs and OPAHs in the atmospheric PM2.5 in spring in Jinan both appeared in the days of haze,while the highest values of the average NPAHs concentration appeared in the dusty daysl.The contribution of MMW and HMW PAHs(52%and 25%)to the total PAHs concentration are greater than that of LMW PAHs(23%).Characteristic ratio analysis and principal component analysis(PCA)were used to identify the main sources of PAHs,NPAHs,and OPAHs in PM2.5 in the spring of Jinan.We also analyzed the secondary generation of NPAHs.It was found that PAHs,NPAHs,and OPAHs in the atmospheric PM2.5 in spring in Jinan are mainly derived from oil and coal combustion,vehicle exhaust emissions,and biomass combustion.The secondary generation of NPAHs in atmospheric PM2.5 in spring in Jinan is mainly catalyzed by OH radicals.The assessment of the risk of human health exposure to PAHs and NPAHs in different populations in the spring atmospheric PM2.5 in Jinan was performed by calculating the life cycle-increased cancer risk(ILCR).It was found that ILCR and total cancer-causing risk gradually increased with age.Growth,in which the toddlers(1-6 years old)stage ILCR is higher than that of children,adolescents and adults(18-30 years old),but the highest value occurs in the adult(30-70 years old)stage.The results of back trajectory analysis show that the pollution of PAHs and their derivatives in PM2.5 is mainly affected by local pollution sources and is also affected by the long-distance transport of air masses from Mongolia and Inner Mongolia,through Hebei Province and Bohai Bay during spring in Jinan.