石家庄市采暖期大气细颗粒物中PAHs污染特征

摘要

Fine particulate matter samples were collected in busy traffic,residential,cultural and commercial areas mixed with traffic areasin Shijiazhuang City from December 2015 to February 2016.Composition and contents of polycyclic aromatic hydrocarbons (PAHs)were analyzed by the national standard HJ 646-2013 of Ambient Air and Stationary Source Emissions-Determination of Gas and Particle-Phase Polycyclic Aromatic Hydrocarbons with Gas Chromatography/Mass Spectrometry.The pollution levels and distribution characteristics of PAHs and the correlation between meteorological parameters and PAHs were analyzed,and the sources of PAHs were parsed.The results showed that average concentrations of PAHs detected in PM10,PM2.5 and PM1.0 samples in the heating season were 397.66,349.09 and 272.35 ng/m3,which were 6.16,4.62 and 4.82 times average values,respectively,in the days before heating day,November 1 to 15,2015.The spatial distribution of PAHs concentrations in these four regions was:busy traffic area ＞ residential area ＞ cultural area ＞ commercial area mixed with traffic areas.The effect of meteorological parameters on PAHs concentrations were studied,and humidity showed significant positive correlation with PAHs in PM10,PM2.5 and PM1.0,with R2 being 0.30,0.37 and 0.33,respectively.Wind speed showed significantly negative correlation with PAHs in PM10,PM2.5 and PM1.0,with R2 being-0.39,-0.53 and-0.26,respectively.Additionally,the number of PAHs monomer correlation in PM1.0 was more than that in PM10 and PM2.5.The diagnostic ratios suggested that coal combustion and motor vehicle exhaust were the predominant sourccs for PAHs in fine particulate matter at Shijiazhuang city during heating season in winter.In addition,cooking oil fumes contributed partly to PAHs in fine particulate matter.%采集2015年12月-2016年2月采暖期石家庄市文教区、交通密集区、居民区和商业交通混合区大气细颗粒物样品,依据HJ 646-2013《环境空气和废气气相和颗粒物中多环芳烃的测定气相色谱-质谱法》分析石家庄市大气细颗粒物中PAHs污染水平及分布特征、气象参数与PAHs相关性,并解析PAHs污染来源.结果表明:石家庄市冬季采暖期大气细颗粒物PM10、PM25和PM1.0中ρ(PAHs)的日均值分别为397.66、349.09和272.35 ng/m3,分别是采暖期前(11月1-15日)的6.16、4.62和4.82倍,并且呈交通密集区＞居民区＞文教区＞商业交通混合区的空间分布特点.相对湿度与细颗粒物PM10、PM2.5和PM1.0中ρ(PAHs)均呈显著正相关,R2分别为0.30、0.37和0.33,而风速与三者呈显著负相关,R2分别为-0.39、-0.53和-0.26;PM10中具有显著相关的PAHs单体数量多于PM10和PM2.5.根据PAHs环数分布特征及特征化合物比值判断,石家庄市冬季采暖期PAHs污染为燃煤与机动车尾气复合型污染特征,同时餐饮油烟也有一定的贡献.