Abstract: The carbon isotope technique has became a potential tool for the source apportionment of organic compounds and widely used to identify the specific sources of PAHs (polycyclic aromatic hydrocarbons) associating with soil, sediment and atmospheric particles. In order to address the sources of atmospheric PAHs in the industrial and commercial districts, the atmospheric PM₁₀ samples were collected by the medium volume samplers, the δ13C (carbon isotopic composition) of PAHs associated with PM₁₀, and emission sources (coal soot and vehicle exhaust) were measured by GC/IRMS, and the contributions of such suspected sources to atmospheric PAHs were calculated according to the carbon isotope mass balance. The results showed that δ13C values of PAHs ranged from -26.0‰ to -24.5‰ in industrial district, and became more depleted in ¹³C with increasing ring size which was the same variation trend as coal soot PAHs. The coal soot was the primary pollution source of industrial district. The δ13C range of atmospheric PAHs in commercial district was from -26.6‰ to -26.2‰, which was more depleted in ¹³C than that of industrial district PAHs. The pollution sources of industrial and commercial districts were significantly different. The pollution sources of industrial and commercial districts should contain other ones except for the vehicle exhaust and coal soot. Specifically, the so-called other source was the biomass burning for industrial district and the crankcase oil for commercial district. The contributions of coal soot and biomass burning emission to industrial district were 59.3% to 70.8% and 29.2% to 40.7%, respectively. This indicated that the industrial district was seriously polluted by coal soot. The contribution of vehicles to commercial district, ranging from 86.1% to 95.8%, included two parts, which were the range of 40.9% to 85.3% for crankcase oil and the range of 8.3% to 54.9% for vehicle exhaust respectively. The contribution of coal soot was the minimum among pollution sources ranging from 4.2% to 13.9%. This indicated that the vehicle was the primary emission source of atmospheric PAHs in commercial district. In further research, a new method to identify the pollution sources accurately and a comprehensive data base about isotope compositions of organic compounds from pollution sources will be required to reveal the contributions of various sources to the specific receptor.