Forty-eight daily time interval PM2.5 samples were collected from December 2006 to January 2008 in an urban site in Shanghai, China. Concentrations and compositions of polycyclic aromatic hydrocarbons （PAHs） were an...Forty-eight daily time interval PM2.5 samples were collected from December 2006 to January 2008 in an urban site in Shanghai, China. Concentrations and compositions of polycyclic aromatic hydrocarbons （PAHs） were analyzed with GC-MS to study the diurnal and seasonal variations and to identify the main emitting sources. The diurnal variation of the PAHs concentrations was greater in the late autumn and winter sampling days, and was greatly influenced by meteorological conditions such as wind speed and ambient temperature. The concentration of PAHs in the mornings （6：30–10：00） increased distinctly, and was high in the late autumn and winter sampling days, indicating the contribution from vehicle emissions during rush hours. The diurnal variation of the high molecular weight PAHs did not seem to be controlled by the shift of gas-particle partitioning due to temperature variation, instead, it could be indicative of the variation in the source. Statistical analyses showed that the concentrations of PAHs were negatively correlated with temperature and wind speed, and positively correlated with relative humidity. Diagnostic ratios of PAHs suggested mixed emission sources of petroleum and coal/biomass combustion for PAHs in the PM2.5 in Shanghai.展开更多
PM2.5, total suspended particles （TSP） and gas phase samples were collected at two sites of Talzhou, a major e-waste dismantling area in China. Concentrations, seasonal variations, congener profiles, gas-particle pa...PM2.5, total suspended particles （TSP） and gas phase samples were collected at two sites of Talzhou, a major e-waste dismantling area in China. Concentrations, seasonal variations, congener profiles, gas-particle partitioning and size distribution of the atmospheric polychlorinated biphenyls （PCBs） were studied to assess the current state of atmospheric PCBs after the phase out of massive historical dismantling of PCBs containing e-wastes. The average ∑38PCBs concentration in the ambient air （TSP plus gas phase） near the e-waste dismantling area was （12,407 ± 9592） pg/m^3 in winter, which was substantially lower than that found one decade ago. However, the atmospheric PCBs level near the e-waste dismantling area was 54 times of the reference urban site, indicating that the impact of the historical dismantling of PCBs containing e-wastes was still significant. Tri-Penta-CBs were dominant homologues, consisting with their dominant global production. Size distribution of particle-bound PCBs showed that higher chlorinated CBs tended to partition more to the fine particles, facilitating its long range air transportation.展开更多
基金supported by the National Natural Science Foundation of China (No. 20877052)the Shanghai Leading Academic Disciplines (No. S030109)
文摘Forty-eight daily time interval PM2.5 samples were collected from December 2006 to January 2008 in an urban site in Shanghai, China. Concentrations and compositions of polycyclic aromatic hydrocarbons （PAHs） were analyzed with GC-MS to study the diurnal and seasonal variations and to identify the main emitting sources. The diurnal variation of the PAHs concentrations was greater in the late autumn and winter sampling days, and was greatly influenced by meteorological conditions such as wind speed and ambient temperature. The concentration of PAHs in the mornings （6：30–10：00） increased distinctly, and was high in the late autumn and winter sampling days, indicating the contribution from vehicle emissions during rush hours. The diurnal variation of the high molecular weight PAHs did not seem to be controlled by the shift of gas-particle partitioning due to temperature variation, instead, it could be indicative of the variation in the source. Statistical analyses showed that the concentrations of PAHs were negatively correlated with temperature and wind speed, and positively correlated with relative humidity. Diagnostic ratios of PAHs suggested mixed emission sources of petroleum and coal/biomass combustion for PAHs in the PM2.5 in Shanghai.
基金supported by the National Natural Science Foundation of China (No.40775084)the Shanghai Leading Academic Disciplines (No.S030109)
文摘PM2.5, total suspended particles （TSP） and gas phase samples were collected at two sites of Talzhou, a major e-waste dismantling area in China. Concentrations, seasonal variations, congener profiles, gas-particle partitioning and size distribution of the atmospheric polychlorinated biphenyls （PCBs） were studied to assess the current state of atmospheric PCBs after the phase out of massive historical dismantling of PCBs containing e-wastes. The average ∑38PCBs concentration in the ambient air （TSP plus gas phase） near the e-waste dismantling area was （12,407 ± 9592） pg/m^3 in winter, which was substantially lower than that found one decade ago. However, the atmospheric PCBs level near the e-waste dismantling area was 54 times of the reference urban site, indicating that the impact of the historical dismantling of PCBs containing e-wastes was still significant. Tri-Penta-CBs were dominant homologues, consisting with their dominant global production. Size distribution of particle-bound PCBs showed that higher chlorinated CBs tended to partition more to the fine particles, facilitating its long range air transportation.
