Characteristics Of Volatile Organic Compounds Pollution In Amblient At Typical National Control Points In Shijiazhuang

In this paper,the typical national control points in Shijiazhuang was selected as the research object.The VOCs in ambient air was studied by establishing SUMMA tank sampling-Gas Chromatography-Mass Spectrometer.The pollution characteristics and characteristic pollutants of VOCs were determined.In addition to routine monitoring,the pollution situation of VOCs was analyzed during the implementation of environmental protection policy in Shijiazhuang City,and the influence of VOCs pollution level before and after the implementation of the policy was obtained.The relationship between VOCs and conventional pollutants and the conversion mechanism of VOCs in air was analyzed.The correlation coefficient?r?established in this paper is between 0.9 901¹.0 000.The relative standard deviation was between 0.29%⁶.35%,and the recovery rate of each component was between 81.75%¹18.19%.According to the method,42 kinds of volatile organic compounds were detected,the concentration range was 0.20²5.22?g·m^-3,and the average concentration of a year was129.95?g·m^-3.The seasonal variation of VOCs is spring<summer<autumn<winter.The characteristic pollutants are Methylbenzene,Benzene,Dichloromethane,sym-Dichloroethane,Methyl chloride,Dichloropropane.In terms of spatial pollution characteristics is Xinan gaojiao<Century Park<hi tech Zone.Their concentrations were116.67?g·m^-3,127.25?g·m^-3,145.73?g·m^-3.The concentration of typical national control point VOCs in Shijiazhuang during the implementation of environmental protection scheme was 134.52?g·m^-3,and after the implementation of the program,the concentration was 149.55?g·m^-3.After the implementation of the program,the concentration of VOCs in Shijiazhuang increased by 11.18%.The correlation between TVOC,characteristic pollutants and AQI,PM_2.5,PM₁₀ was higher,but the correlation between methyl chloride and AQI,PM_2.5,PM₁₀ was poor;VOCs and each characteristic pollutant were negatively correlated with O₃,and the correlation was poor.The SOA was 1.67?g·m^-3.The VOCs with the highest contribution to ozone formation potential?OFP?are:Methylbenzene,Propylene,m-Xylene,p-Xylene,o-Xylene,Ethylbenzene,1,2,4-Trimethylbenzene,Benzene,n-Hexane.The HQ was between8.82·10^-72.36·10^-1,and the hazard index?HI?was 3.67·10^-1,and the carcinogenic risk value was 6.96·10^-5.