| Atmospheric fine particulate matter(PM2.5)pollution has become an important environmental problem in the world,especially for the air pollution in China.PM2.5 are highly toxic due to the adsorption of a large number of toxic substances,which including polycyclic aromatic hydrocarbons?PAHs?and brominated flame retardants?BFRs?,which were considered as typical persistent organic pollutants.PM2.5 can enter into human body via inhalation and endanger human health.With the continuous development of urbanization and industrialization in China,the emissions of PAHs and BFRs are increasing rapidly.PAHs,produced by natural or man-made incomplete combustion,are widespread,persistent,bioaccumulative,biotoxic in the environment,and some of them are carcinogenic.Polybrominated diphenyl ethers?PBDEs?,the traditional BFRs,are usually added into materials?such as electronic equipment,plastics,and textiles?as flame retardants to prevent the spread of fire.In recent years,since PBDEs have been banned by the Stockholm Convention,alternative flame retardants,such as novel brominated flame retardants?NBFRs?and dechlorane plus?DPs?have gradually occupied the market.Meanwhile,their environmental pollutions have gained more and more attention.In this study,a total of 184 active air samples were collected from a fixed station in Dalian from 2016 to 2018.The concentrations,compositions,seasonal variations,influencing factors,gas-PM2.5 partitions,and sources 15 PAHs,14 BFRs,and 2 DPs in the atmosphere in Dalian were investigated.The total concentrations of 15 PAHs were in the range of 49.4-179 ng/m3with the concentration in heating period?117±35.3 ng/m3?being 1.75 times of that in non-heating period?66.9±15.3 ng/m3?.The dominant PAH congener was Phe with an average proportion of 42.1%.Low-melecular-weight PAHs dominated in all air samples.The seasonal characteristics followed the trend of winter>spring>summer>autumn.The average concentration of PAHs in the gas phase?65.2±18.2 ng/m3?was slightly higher than that in PM2.5?20.9±25.8 ng/m3?.The total concentrations of 14 BFRs in both gas phase and PM2.5were in the range of 551-16800 pg/m3.Due to coal combustion in the heating period,the BFR concentrations in winter and spring were significantly higher than those in summer and autumn.The dominant BFR congener was BDE209 with an average percentage of 97.7%.The source apportionments of PAHs and BFRs were conducted by principal component analysis?PCA?,gas-PM2.5 partitioning assessment,and correlation analysis between PAHs,BFRs,and six criteria air pollutants.The results showed that combustion were the main sources of PAHs in the atmosphere of Dalian.The BFRs in gas phase were mainly from BFR contained materials,while the BFRs in PM2.5 were mostly produced by combustion.The gas-PM2.5partitioning showed that temperature has a significant effect on gas-PM2.5 partitioning of PAHs and BFRs.Except Acy,Ace,HBB,and BEH-TEBP,most PAHs and BFRs have reached equilibrium between air and PM2.5. |
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