Distribution of persistent organic pollutants (POPs) in atmospheric particles during district heating period (DHP) and non-district heating period (N-DHP) in Shandong province, China

Persistent organic pollutants (POPs), including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), phthalic acid esters (PAEs), and polychlorinated biphenyls (PCBs), were systemically investigated in total solid particles (TSPs) sampled at seven sites in Shandong province, China. The congener profile and space distribution were compared during district heating period (DHP) in winter and non-district heating period (N-DHP) in spring. The air pollution at in-land sites was worse than that at seashore sites due to the different ventilation conditions and pollutant sources. The concentrations of PAHs associated to the distribution of TSP, severer in DHP, since coal burning was the major source for both pollutants, according to the analysis of these results and diagnostic ratios. FLT, PYR, and BBF were top PAH congeners by specific mass concentrations. On the profile, OCPs, PCBs, and PAEs were more related to the ambient temperature due to the evaporation and revealed higher abundancy in N-DHP than in DHP. Based on the diagnostic ratio analysis, the source of pollution was more likely local than remote.