Particle-bound polychlorinated dibenzo-p-dioxins and dibenzofurans in the atmosphere of Guangzhou, China

A short-term sampling scheme was devised to determine the levels of particle-bound polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in Guangzhou atmosphere and to evaluate the impact of PCDD/Fs on the lives of the inhabitants in Guangzhou. Samples were collected from four different districts of Guangzhou City, and the results indicated that industrial activities had tremendous influence on the levels of atmospheric PCDD/Fs in these districts. The mean PCDD/Fs concentrations (mean I-TEQ values) for Huadu, Liwan, Tianhe and Huangpu districts were 3815 fg m−3 (104.6 fg I-TEQ m−3), 12 777 fg m−3 (430.5 fg I-TEQ m−3), 6963 fg m−3 (163.7 fg I-TEQ m−3) and 10 953 fg m−3 (769.3 fg I-TEQ m−3), respectively, which were higher than the concentration ranges for other cities in the world. The mean concentrations of particulate organic carbon (OC) and elemental carbon (EC) were 17.61±0.94 and 3.17±0.21 μg m−3 for Huadu district, 44.18±2.29 and 13.32±0.75 μg m−3 for Liwan district, 33.53±1.72 and 9.89±0.56 μg m−3 for Tianhe district, and 29.52±1.53 and 8.87±0.53 μg m−3 for Huangpu district, respectively. The relationship between PCDD/Fs concentrations and OC and EC concentrations demonstrated that EC could be a better predictor for the concentration of PCDD/Fs. Detailed source analysis indicated that the PCDD/Fs in Guangzhou were derived from small diffuse combustion sources, e.g., traffic sources, domestic burning of fossil fuels, non-industrial combustion sources and industrial combustion sources. Results of daily intake of PCDD/Fs by inhaling air suggested that the inhalation exposure of PCDD/Fs by the inhabitants in Liwan district is relatively high.