| Organic pollutants are among the most important factors influencing the urban air quality and human health. Polychlorinated biphenyls (PCBs), notorious for their cancerogenic, teratogenic and mutagenic effects, are one kind of anthropogenic semivolatile persistent organic pollutants (POPs). As an economic developing area with high degrees of industrialization and urbanization, Guangzhou city is being exposed to heavy air pollution. How about the PCBs pollution and their temporal and spatial distribution in the atmosphere of Guangzhou? This question will be preliminarily answered through a pilot study. Polycyclic aromatic hydrocarbons (PAHs) are another kind of widespread semivolatile organic compounds. Because high-erected buildings are very popular in city residential areas recently, it is important to evaluate the horizontal and vertical distributions of PAHs to reveal the respiring exposure of the residential population within those high buildings. To reach these aims, the following two studies are carried out.1. Dinghu nature reserve in Zhaoqing city was chosen as the regional environment background of atmospheric polychlorinated biphenyls (PCBs) in the Pearl River Delta (PRD) area. As a representative of cities in the PRD, Guangzhou city was studied for the temporal and spatial distributions of its atmospheric PCBs.2. Among various PAH emission sources, the traffic source has been known to be the greatest contributor to atmospheric PAHs. According to building surroundings and road configuration, we selected three residential buildings in urban area of Guangzhou. Inhalable PM2.5 indoors and outdoors was selected as the sampling target and PM2.5-contained PAHs were analyzed for the purpose of investigating their horizontal and vertical distributions.The study reached the following conclusions:(1) The distributions of particulate PCBs in spring are similar to those in winter, with similar concentration levels in the two seasons. While for summer, the levels of particulate PCBs are lower than those in spring and winter, with poor correlations to the latter. In summer, the average PCBs concentration is 216.94 pg/m3, of which the gas-phase concentration is 5.47 times as that of particle phase, with value of 183.42 pg/m3. The two most contributors to ΣPCBs are tri- and tetrachloro- biphenyl homologues with contribution of 86.41%. In winter, the average PCBs concentration in the air is 176.43 pg/m3, with gaseous PCBs concentration of 123.20 pg/m3, which is only 2.31 times as that in particle phase. Compared with other studies overseas, the PCBs concentration in the background of PRD was very high, with larger contribution of particulate PCBs to totalatmospheric PCBs, in both summer and winter seasons.(2) In Guangzhou atmosphere, the average PCBs concentration is 501.36 pg/m3 in spring, of which the concentrations of particle and gas phase were 100.34 pg/m and 401.02 pg/m3 respectively, with the latter 4.00-time the former. In summer, the gaseous PCBs concentration was averaged to 528.24 pg/m3, which was 1.32 times as that in spring; the particulate PCBs concentration was averaged to 123.08 pg/m3. In winter, the atmospheric PCBs concentration was similar to that in spring, with averaged value of 448.78 pg/m3, but was only 68.90% of the corresponding value in summer, of which the most contribution was made by gas-phase PCBs. In three seasons, the atmospheric PCBs profiles, which were similar to that of Aroclorl242, were positively correlated with those in sediments from Guangzhou section of Pearl River.(3) PL" and K0& were suitable to use to describe the distributions of atmospheric PCBs between gas and particle phases in Guangzhou.(4) In Guangzhou, the winter concentrations of atmospheric PCBs decreased in the order of urban, suburban and background. The average PCBs concentration (448.78 pg/m3) in urban area was 1.61 times as that in suburban (278.01 pg/m3), 2.54 times as that in background (176.43 pg/m). Among the urban, suburban and background, the geographically re...
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