According to Fig. 4,we could conclude that traffic emissions and coal combustion were most important pollution sources in four seasons except for summer. This was in agreement with a former researcher (Liu et al., 2007), who revealed that road dust PAHs in central Shanghai came from the mixing of traffic and coal combustion. Coal smelting and coal combustion was higher in winter than in summer due to the more use of coal in winter. No obvious difference in contribution was demonstrated in spring and autumn. The potential sources of PAHs identified by PMF method are categorized as (1) mobile sources such as traffic emissions, the chief source of pollution, oil spill and leakages, (2) stationary sources such as coal smelting and combustion emissions.Compared with other research of PMF apportionment for dry and wet deposition in Shanghai (Wang et al., 2016a,b), the contribution of oil spill and leakages is high. Due to the sampling site closed to gas station, the contribution of oil spill and leakages maybe overestimated. The area is heavily industrialized with power plant and heavy traffic, the combustion of coal and oil is a significant emission source. The impact of surrounding industries should be further studied.