Study On The Pollution Features Of Polycyclic Aromatic Hydrocarbons In Particles In Ambient Air Of Jinan

PAHs (Polycyclic Aromatic Hydrocarbons, PAHs)is a broad kind of organic pollutants that existed in the environment widely. Because of its carcinogenic, teratogenic and mutagenic effect and it can exist in the environment chronically,the PAHs has been listed in the typical persistent organic pollutants. In 1976, EPA listed 16 kinds of PAHs in the priority pollutants.China also listed benzo[a]pyrene (BaP) in the Ambient Air Quality Standard(GB3095-1996).Particulates in ambient air have big specific surface areas and enrich PAHs in ambient air easily,so they are harmful to the environment and human health.In all,the study of the pollution features and change rules of PAHs in particulates in ambient air has vital significance and application value.This paper refered to massive literatures,summarized and analysed the structure, nature, sources, harm, treatment of PAHs and the civil and abroad analysis methods and research present situation about PAHs.Take Jinan to be research area,this experiment gathered the TSP in ambient air of seven locations of Jinan, researched the analysis methods about sixteen kinds of priority control PAHs,disscussed pollution characteristic and Spatio-Temporal distribution patterns of sixteen kinds of PAHs of Jinan and revealed the pollution condition of PAHs in TSP in ambient air of Jinan.This paper improves the scientific basis for organic pollutants hazard evaluation of ambient air and the study of the compound pollution and health effect of air pollutants of Jinan.This paper used TH-150C type intelligent middle flow TSP sampler to gather particle samples in the ambient air of seven locations of Jinan, used accelerated solvent extraction to extract PAHs and used single factor experimental methods to optimize extraction conditions. Extraction liquid was evaporated by the rotary evaporator, purged by the organomation, filtrated by the silica gel column, purged by the organomation again and analyzed by GC-MS eventually.It is quckily and accurately to determine the concentration of PAHs using this method.Through optimizing extraction methods, perfecting the whole pre-treatment, determining and analyzing the PAHs in TSP in ambient air of seven locations of Jinan.this paper got the following main conclusions:(1)Through optimizing extraction conditions of ASE by using single factor experimental methods,this experiment got the best extraction conditions are those its extraction temperature is 100℃, its static extraction time is 5minutes,its cycles are 2 times and the volume ratio of acetone and n-Hexane is 1:1.(2) The experiment set up standard curves and regression equations of 16 PAHs and the correlation coefficients are all above 0.999.(3)The experiment used ASE to extract PAHs and used GC-MS to analyze PAHs in TSP in ambient air.We got that the recovery is between 82.5% and 106.8% and the relative standard deviation is between 1.14% and 6.89%.According to triplicate signal to noise ratios to calculate the detection limits,we got the detection limits of 16 kinds of PAHs in TSP in ambient air are between 1.875 ng/g and 5.944ng/g.(4)The total concentration of 16 kinds of PAHs in TSP in ambient air in different seasons of Jinan center's order is winter>autumn>spring>summer.The tetracyclic and pentacyclic PAHs are the most PAHs of 16 kinds of PAHs in TSP in ambient air in four seasons. Its summation is 75.872%,73.083%,70.876%,75.348% of the total concentration in four seasons respectively and the following PAHs are six rings PAHs.So the high and middle rings PAHs are main PAHs of 16 kinds PAHs in TSP in ambient air in Jinan center.(5)The concentratin variation of BaP in TSP in ambient air in different seasons in Jinan center is winter>autumn>spring>summer.The concentratin of BaP in TSP in ambient air in four seasons surpasses the limits recommended by WHO.But only the concentratin of BaP in TSP in ambient air in winter surpasses China's state standards and the pollution is serious. Moreover, the concentratin of BaP in TSP in ambient air in different seasons in Jinan center has good correlation with∑PAHs.So we can use the concentratin of BaP to response the pollution level of the total concentration of PAHs in particulates in ambient air.(6)After the contrast of the total concentration of 16 kinds of PAHs in TSP in ambient air in non-heating period in seven locations of Jinan, we get a result that Zhangqiu has the highest concentration, the monitoring station has the lowest concentration and the following locations are Changqing, Zhonggong, Jiyang, Paomaling and Gongyebeilu.(7) After the contrast of the total concentration of 16 kinds of PAHs in TSP in ambient air in sandstorm period in seven locations of Jinan,we get a result that Changqing has the highest concentration, Paomaling has the lowest concentration and the following locations are Zhonggong,Jiyang,Zhangqiu, the monitoring station and Gongyebeilu. In addition, Zhonggong, Jiyang and Zhangqiu have the similar total concentration of 16 kinds of PAHs.(8) After the contrast of the total concentration of 16 kinds of PAHs in TSP in ambient air in heating period in seven locations of Jinan, we get a result that Changqing has the highest concentration, Paomaling has the lowest concentration and the following locations are Jiyang, Zhonggong, Gongyebeilu, the monitoring station and Zhangqiu.(9) The total concentration of 16 kinds of PAHs in TSP in ambient air in seven locations shows the same law what is non-heating period< sandstorm period< heating period and The total concentration of 16 kinds of PAHs in TSP in ambient air in heating period is much higher than non-heating period and sandstorm period.(10)The four rings and five rings PAHs have the highest concentration and the two rings NaP has the lowest concentration. So the middle and high rings PAHs are main PAHs in TSP in ambient air in Jinan and we should strengthen the monitoring and control of the middle and high rings PAHs.