In this study the concentrations and distribution of sixteen polycyclic aromatic hydrocarbons (PAHs) were investigated in gas and total suspended particle (TSP) samples collected during daytime and night time. The sampling locations included an electronic waste dismantling workshop (EW), a plastic recycling workshop (PW) and a waste incineration field (WF) in Guiyu, China. A large residential area (RA) in this region was used as a control site. In the daytime, the highest concentration was found at WF (1041 ng m(-3)): while in the night time the highest concentration was found outside of EW (744 ng m-3). Comparison between work hours (daytime) and rest hours (night time) displayed that the total PAHs (gas + particulate phase) concentrations and the percentages of PAHs associated with TSP were higher at night than those in the daytime in all sampling workshops except WF. Source diagnostic-ratio analysis revealed that unwanted materials and smoldering honeycomb coals were the main sources of PAHs in EW, WF and PW. Benzolalpyrene equivalent [BaPeq] concentrations calculated by using the toxic equivalent factors [TEFs] suggested that the occupational exposure levels were not significantly high when compared with other occupational exposure. Additionally, our study suggested that the smoldering of unwanted materials could produce much more toxic PAHs compounds. (C) 2011 Elsevier B.V. All rights reserved.