Atmospheric PM_2.5/PM₁₀-associated Flame Retardants, Chlorinated Polycyclic Aromatic Hydrocarbons And Their Parent Compounds In A Suburban Are Of Shanghai, China

Organic pollutants are among the most important factors influencing urban air quality andhuman health. In this study, PM_2.5and PM₁₀samples were collected in the Baoshan district ofShanghai city from October to April of2012. Organic carbon （OC） and elemental carbon （EC）were detected and their distribution characteristics were illustrated. Temporal variations andsources of the flame retardants （FRs）, Chlorinated polycyclic aromatic hydrocarbons （ClPAHs）and parent polycyclic aromatic hydrocarbons （PAHs） in atmospheric PM_2.5and PM₁₀wereanalyzed in detail as well. The major findings and conclusions are as follows:（1） The average24h PM_2.5and PM₁₀concentrations in Shanghai were90.5μg/m³and150μg/m³, respectively. This is2.59and1.5times higher than the National Ambient Air QualityStandards in China (PM_2.5,35μg/m³; PM₁₀,100μg/m³). The ratio of PM_2.5to PM₁₀is0.63,indicating that secondary pollution and combustion are the major sources for this particulateatmospheric pollution.（2） In PM_2.5and PM₁₀, the24h mean concentration of Polybrominated diphenyl ethers（PBDEs） was15.8pg/m³and24.1pg/m³respectively: the12h daytime mean concentration ofPBDEs was7.88pg/m³and25.1pg/m³respectively: and the12h nighttime mean concentration ofPBDEs was17.2pg/m³and31.9pg/m³respectively The24h mean concentration ofpolybromodiphyl ethane （DBDPE） was0.93pg/m³and2.32pg/m³respectively: the12h daytimemean concentration of PBDEs was0.79pg/m³and3.36pg/m³respectively: and the12h nighttimemean concentration of PBDEs was0.71pg/m³and2.36pg/m³respectively. There are no obviousindividual BDE concentration differences between each of the samples except for BDE-209,indicating that Deca-BDEs in atmospheric particulates is of the point source pollution type. Thisaccumulation has allowed Penta-BDEs and Octa-BDEs to reach their equilibrium in theatmosphere of Shanghai.（3） The mean concentration of7parent PAHs in PM_2.5and PM₁₀was10.4ng/m³and12.6ng/m³, respectively. The mean concentration of BaP in PM_2.5and PM₁₀was2.52ng/m³and3.27ng/m³, respectively. No obvious difference was observed between these7carcinogenic PAHconcentrations in PM_2.5and PM₁₀, indicating that high ring PAHs accumulate more on fineparticulate matter. （4） Total concentrations of ClPAHs associated with atmospheric PM_2.5and PM₁₀were9.52pg/m³and12.6pg/m³respectively, PM_2.5associated ClPAHs values were slightly lower thanthose associated with PM₁₀. This accounted for an average of81%of the PM₁₀associated ClPAHconcentrations. The concentration of6-ClBaP, a high-molecular-weight ClPAH, was thepredominant congener in both PM₁₀and PM_2.5.6-ClBaP （31%） was followed in abundance by1-ClPyr （13%）,9-ClPhe （12%）,3-ClFlu （11%）, and7-ClBaA （11%） in PM₁₀.6-ClBaP contributed29%of the∑ClPAH concentrations in PM_2.5, followed by9-ClPhe （14%）,1-ClPyr （14%）,3-ClFlu （11%）, and7-ClBaA （8%）.（5） In our study, we investigated the relationships between ClPAH and parent PAHconcentrations, particulate mass, and total organic carbon. Significant positive correlations werefound between∑ClPAHs,9,10-Cl2Phe,3-ClFlu,8-ClFlu,3,4-Cl2Flu,1-ClPyr,7-ClBaA, and6-ClBaP, and their corresponding parent PAHs in PM₁₀. Similar significant correlations were alsofound in PM_2.5with the exception of6-ClBaP and9,10-Cl2Phe. Here the total organic carbon inthe particulate was taken into consideration. There was significant correlation between3-ClFlu,8-ClFlu,3,4-Cl2Flu,1-ClPyr,7-ClBaA,6-ClBaP and∑ClPAHs and the total carbon levels ofboth PM₁₀and PM_2.5. The airborne carbonaceous materials elemental carbon and organic carbonare the largest contributors to the particulate burden. This correlation suggests the possibility ofClPAH adsorbing to atmospheric particles, principally PM containing organic carbon.