大型石化企业邻近区域大气沉降中多环芳烃赋存特征及源解析

Distribution Characteristics and Source Apportionment of Polycyclic Aromatic Hydrocarbons in Atmospheric Deposition in Areas Adjacent to a Large Petrochemical Enterprise

为探讨石化企业对周边环境影响,以大型石化企业邻近工业区和居民区大气沉降多环芳烃为研究对象,连续采集2017年3月~2018年2月期间共计12个月的大气沉降样品,分析了大气沉降中多环芳烃沉降通量及组成特征,并采用正定矩阵因子法对多环芳烃来源进行解析.结果表明,邻近区域15种多环芳烃沉降通量范围为549~18845 ng·(m^(2)·d)^(-1),平均值为2712 ng·(m^(2)·d)^(-1),其中工业区全年沉降通量是居民区的1.36倍.冬春季节多环芳烃沉降通量高于夏秋季节,1月工业区沉降通量最高,10月居民区最低.菲(Phe)、苯并[b]荧蒽(BbF)和荧蒽(Fla)是研究区域大气沉降中的优势单体;夏秋季节两个区域单体差异明显,居民区中苯并[b]荧蒽(BbF)、苯并[k]荧蒽(BkF)和苯并[ghi]苝(BghiP)等单体沉降通量高于工业区,5,6环多环芳烃占比较高,表明交通源对居民区有较大贡献;工业区3环占比较高,指示石油挥发源.源解析表明,交通源、石油源和燃煤源是研究区域大气沉降中多环芳烃的主要来源,冬春季节3种来源对工业区和居民区多环芳烃的贡献率分别为45.7%、18.4%、35.9%和46.3%、21.4%、32.3%;夏秋季节交通源对居民区的贡献高达65.2%,石油源对工业区的占比增加到35.5%,由于高空排放及有利扩散条件影响,燃煤源贡献率明显降低.

In order to explore the influence of polycyclic aromatic hydrocarbons(PAHs)emissions by petrochemical enterprises on the surrounding environment,atmospheric deposition samples of the PAHs were collected in the industrial and residential areas adjacent to a petrochemical enterprise from March 2017 to February 2018.Deposition fluxes and the composition of PAHs were studied.The source of PAHs was analyzed by a positive matrix factor(PMF)model.The results showed that the deposition fluxes ofΣ15PAHs ranged from 549 ng·(m^(2)·d)^(-1)to 18845 ng·(m^(2)·d)^(-1),with an average of 2712 ng·(m^(2)·d)^(-1).The flux ofΣ15PAHs in the industrial area was 1.36 times greater than that in the residential area.The deposition fluxes of PAHs in winter and spring were higher than those in summer and autumn.The deposition flux was highest in January in the industrial area and lowest in October in the residential area.Phe,BbF,and Fla were the dominant monomers.There was noticeable difference of monomers between the industrial area and the residential area in summer and autumn.The monomers,such as BbF,BkF,and BgP,in the residential area were higher than those in industrial area,and the proportion of 5,6 rings was higher,which indicated that traffic contributed more to the residential area;3 ring PAHs in industrial area had a higher proportion,which pointed out that their main source was petroleum volatilization.Based on the quantitative source analysis,the PAHs in atmospheric deposition were mainly from traffic emissions,petroleum volatilization,and coal combustion.Three sources of PAHs accounted for 45.7%,18.4%,35.9%,and 46.3%,21.4%,and 32.3%,respectively,in the industrial area and the residential area in winter and spring.In summer and autumn,the contribution of traffic sources to the residential area was as high as 65.2%,and the proportion of the petroleum source to the industrial area increased to 35.5%.Due to high-altitude emissions and favorable diffusion conditions,the coal combustion contribution was significantly reduced.