| Polycyclic aromatic hydrocarbons(PAHs)have been the targets of researchers and government due to its carcinogenic,teratogenic and mutagenic capacity and PAHs have been known as Persistent Organic Pollutants(POPs).To investigate the concentration characteristics,emission and potential regional sources,and health risks to humans,PAHs in gas phase and on PM2.5 were analyzed and discussed.Results of the paper can provide references for other researchers and monitoring sites and can also provide theoretical basis for pollution controlling.Sampling was conducted via MH1200-F sampler during Oct.2015 to Jul.2016 atop the building of the college of environmental science and engineering in Shandong University,Jinan.Concentration data were analyzed via High Performance Liquid Chromatograph(HPLC).Concentration levels,distribution between gas phase and PM2.5,emission sources and potential source regions,and health risk assessment were discussed in this paper.The most abundant PAH in gas phase was PHE,with an average concentration of 49.91.ng/m3,ranging from 5.03 to 145.76 ng/m3.The mean concentration of gaseous PAHs was 107.88 ng/m3.FLA and BbF were the most two abundant PAHs in PM2.5,with average concentrations of 4.19 ng/m3(range:0.00-30.53 ng/m3)and 3.92 ng/m3(range:0.00-17.16 ng/m3),respectively.The average concentration of PAHs in PM2.5 was 26.74 ng/m3 and was about 25%of the gaseous PAHs concentration.The concentration of PHE was the highest of the total PAHs,ranging from 6.58 to 146.60 ng/m3 and the mean concentration of PHE was 51.66 ng/m3.PAHs of 2-3 rings were mainly distributed in gas phase and the concentration of 4-ring PAHs in PM2.5 was almost 3 times the concentration in gas phase.5-6 rings PAHs were fairly found in gas phase and most of them were attached on PM2.5.Emission sources and potential source regions were investigated via Positive Matrix Factorization(PMF)and Potential Source Contribution Fuction(PSCF).PMF analysis was utilised to identify emission sources of PAHs,The model was run with different number of factors ranging from 3 to 7 and obtained the optimum solution with 4 factors using the random seed mode for PAHs in gas phase and PM2.5.For gaseous PAHs,identified sources were petroleum sources(10%),diesel vehicles(12%),coke oven source(41%)and coal combustion(37%).For PAHs on PM2.5,identified sources include petroleum combustion(6%),vehicle sources(32%),coke oven source(15%)and coal combustion(47%).PSCF analysis was utilised to estimate possible emission regions of PAHs in Jinan,finding that there were four clusters influencing the pollution of PAHs:L(27.9%),NE(18.1%),NW(23.0%)and S(31.0%).PAHs in Jinan were mainly attributed to air masses from cities around Jinan and provinces nere Shandong attributed the pollution of PAHs in Jinan,too.Cancer risk assessment and the excess cancer risk level of atmospheric polycyclic aromatic hydrocarbons in Jinan was conducted,showing that BaP TEQ of the vast majority of PAHs exhibited similar sequence:autumn&winter>spring&summer.The risk of excess carcinogenic risk of adults is within the maximum acceptable range while it of children in Jinan is in the same level with the criterion of daily activities. |
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