Polybrominated Diphenyl Ethers And Polychlorinated Biphenyls In Indoor And Outdoor Air Of Urban Areas

Polybrominated diphenyl ethers(PBDEs) and Polychlorinated biphenyls(PCBs) are two classes of halogenated persistent organic pollutants(POPs),which have potential toxicity to human being. Cities are pollution sources of PBDEs and PCBs.As the largest industial city in China,the production and usage of polybrominated diphenyl ethers as flame retardants in products such as electrical and electronic products are intensive in Shanghai. Since not chemically bound to materials,PBDEs can be easily released and their environmental concentrations are rising.Air is primary transport medium and an important sink of PBDEs.Indoor air is particularly important to human health because of the long exposure time(90%) and elevated concentration of contaminants.So,reseaches on PBDEs in the indoor and outdoor air in typical cities are important scientifically and practically.By far,only one reseach on PBDEs in the indoor and outdoor air in Guangzhou was reported using high volume air sampler,which is expensive,unable to collect samples at multi-sites simultaneously and thus the results are not adequate for comparison,and not suitable for popularization for its noise and power consumption.Using polyurethane foam disk to collect air samples through diffusive adsorption,PUF-PAS has been more and more widely used because of cost-effective,simultaneous monitoring at multi-sites and consequently with comparable results,no need for electricity and noise free operation.Taizhou of Zhejiang province is one of the two major e-waste dismantling areas in China.More than two million tons of e-wastes were dismantled there every year.Centralized and standardized management on the e-waste dismantling activities is adopted by the local government of Taizhou in recent years.Through research on the atmospheric PBDEs and PCBs,effectiveness of the management measures can be assessed,which can provide scientific basis for the healthy development of e-waste dismantling industry in China.Better understanding of the release process of PBDEs and PCBs from products can be achieved through comparative study of the e-waste dismantling area and urban site.Shanghai(electrical and electronic products producing and using area) and Taizhou of Zhejiang province(e-waste dismantling area) were thus selected as the reseaching sites for PBDEs and PCBs in indoor and outdoor air.Passive air samplers were used to investigate the concentrations,seasonal variations,congener profiles,possible sources and human inhalation exposure to PBDEs in indoor and outdoor air and indoor dry deposition of Shanghai for the first time.High volume air sampler were used to collect atmospheric samples at the e-waste dismantling site and an urban comparing site in Taizhou to systemantically investigate the concentrations,seasonal variations,congener profiles, gas-particle partitioning,size distribution and correlations of OC/EC with PBDEs and PCBs for the first time.The major findings are listed below: 1) The average outdoor air concentrations of PBDEs of Shanghai in winter(829.9±556.8 pg m^-3) was 2 times higher than that of summer(468.0±334.8 pg m^-3),which was mainly caused by the variations of meteorological conditions(atmospheric mixing heights,wind direction) and pollution sources.Congener profiles showed that BDE-209 was the dominant component(winter:99±1%, summer:95±3%),which was consist with the higher wind speed and consequently more particles can be trapped by the passive air samplers in outdoor air since BDE-209 was mainly in the particulate phase.Industrial zones are the key sources of PBDEs,which was more important than the emissions of PBDEs from products in daily usage.PBDEs concentrations in central urban areas were higher than that of suburban areas because of the intensive usage of PBDEs containing products.PBDEs concentrations in the near ground places were more affected by the local environment.2) The indoor air concentrations of PBDEs in offices of Shanghai(winter:139.8±107.5 pg m^-3, summer:401.1±551.5 pg m^-3) were higher than that of homes(winter:97.5±70.7 pg m^-3,summer: 300.0±246.6 pg m^-3),consisting with the intensive usage of electric and electronic equipments in offices.The indoor air concentrations of PBDEs in homes and offices in summer were about 3 times that of winter.Congener profiles showed that BDE-209 was the major component(home:winter:73±20%,summer:67±24%;office:winter:55±24%,summer:45±25%),indicating that Deca-BDE was the major commercial PBDEs used in Shanghai.Penta-BDE was also used and their proportions in offices were higher than that of homes.Octa-BDE was very rare there.The usage of electric and electronic equipments was the main source of PBDEs in indoor environment,and interior decoration and furniture were of minor importance.PBDEs concentration variations were large in different homes and offices(16-25 times).Besides types and ages of electric and electronic equipments,the usage time and ventilation habits are also important.In addition to indoor sources,PBDEs levels in outdoor air also had some impact on the indoor air,and this was especially true in summer days when the ventilation was much more frequent.Researches on the indoor air of stores selling household electrical appliances showed that electric and electronic equipments was the sources of PBDEs,and PBDEs was still being used in the new products,indicating that the indoor air concentration of PBDEs(especially BDE-209) will retain high level for many years.3) The inhalation exposure of∑₁₆PBDEs were 3.4±2.4 and 6.8±6.5 ng day^-1 in winter and summer respectively for adults in Shanghai,which was comparable to that of Birmingham of UK and Ottawa of Canada,but higher than that of Kuwait.4) The particulate deposition flux of PBDEs in homes and offices were 10.9±8.2 and 14.2±11.9 ng m^-2 day^-1 respectively in Shanghai,and offices were higher than that of homes,ranked in the middle level comparing with other cities around the world.The particulate deposition flux in the offices was relatively low than that of homes,but this was contrary for the concentration of PBDEs in the particle,which was also significantly higher the outdoor particles.The indoor deposition flux of PBDEs mainly correlated with the flux of particle depositon,the quantity and using time of electrical and electronic products.No obvious correlations were found between the indoor deposition flux of PBDEs with the interior decoration and the amount of furniture.Congener profiles showed that BDE-209 was the major congener(88.2-99.2%),indicating that Deca-BDE was the major commercial PBDEs product being used in Shanghai.5) The atmospheric concentration of PBDEs near the e-waste dismantling area in Taizhou(1662 pg m^-3,gas+particle phase) was much lower than that of Guiyu,another major e-waste dismantling area in Guangdong province of China,indicating that strict regulating measures and centralized management of the e-waste recycling activities can greatly reduce the pollutants emission.But it was about 7 times of the values from the reference urban site,indicating that the e-waste dismantling activities can significantly elevate the atmospheric concentration of PBDEs.BDE-209 was the major component of the airborne PBDEs in Taizhou,accounting for about 70%of the total PBDEs, indicating that Deca-BDE was the major commercial PBDEs contained in the E-wastes dismantled at FJ,and Penta-BDE and Octa-BDE products were also used,consisting with the fact that e-wastes in Taizhou were imported from all over the world.Gas-particle partitioning analysis suggested that the dominant mechanism was probably adsorption onto particle surface in summer and absorption by the organic matter in winter.Size distribution showed that∑₁₂PBDEs was mainly in the finer particle (PM_2.5),while BDE-209 was mainly in coarse particles,which could not be transported too far from the sources.In PM_2.5,∑₁₃PBDEs were manirdy in the ultrafine particles(＜0.5μm,52%).Percentiles of PBDEs congeners in different sized particles of PM_2.5 were similar to each other.6) The atmospheric concentration of PCBs near the e-waste dismantling area in Taizhou(12407±9592 pg m^-3,TSP plus gas phase) was substantially lower than the decade ago result(～3%),indicating the declining trend of atmospheric PCBs level there.The atmospheric PCBs level in Taizhou was also much lower than Guiyu,another e-waste dismantling area in China,indicating the centralized and standardized management adopted by the local government of Taizhou in recent years has made some progress.Though declining,the atmospheric PCBs level near the e-waste dismantling area was 54 times of the urban comparing site,indicating the PCBs pollution was still significant there,and the historically polluted soil was an important source.Tr-PeCBs were dominant homologues(～87%), consisting with their dominant global production.Gas-particle partitioning of PCBs showed that the dominant mechanism might be adsorption onto particle surface.Size distribution of PCBs showed that higher chlorinated CBs tended to partition more in the fine particles(PM_2.5),facilitating its long range air transportation.In PM_2.5,PCBs were maninly in the ultrafine particles(＜0.5μm,43.9%).The concentration of PCBs in per unit mass decreased with the size.Lower chlorinated congeners were found more in the 1.3-2.5μm cut than other size cuts.