Twenty-six ambient air samples were collected around a municipal solid waste incinerator (MSWI) in the summer and winter using polyurethane foam passive air samplers, and analyzed to assess the spatial and seasonal distributions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs). Three stack gas samples were also collected and analyzed to determine PCDD/F (971 pg m(-3) in average) and PCB (2,671 pg m(-3) in average) emissions from the MSWI and to help identify the sources of the pollutants in the ambient air. The total PCDD/F concentrations in the ambient air samples were lower in the summer (472-1,223 fg m(-3)) than the winter (561-3913 fg m(-3)). In contrast, the atmospheric total PCB concentrations were higher in the summer (716-4,902 fg m(-3)) than the winter (489-2,298 fg m(-3)). Principal component analysis showed that, besides emissions from the MSWI, the domestic burning of coal and wood also contributed to the presence of PCDD/Fs and PCBs in the ambient air. The PCDD/F and PCB spatial distributions were analyzed using ordinary Kriging Interpolation and limited effect was found to be caused by emissions from the MSWI. Higher PCDD/F and PCB concentrations were observed downwind of the MSWI than in the other directions, but the highest concentrations were not to be found in the direction with the greatest wind frequency which might be caused by emissions from domestic coal and wood burning. We used a systemic method including sampling and data analysis method which can provide pioneering information for characterizing risks and assessing uncertainty of PCDD/Fs and PCBs in the ambient air around MSWIs in China.