Contiguous hourly variations and relativeness of polycyclic aromatic hydrocarbons and their chlorinated derivatives in urban PM2.5

Abstract

The time-resolved analysis of ambient polycyclic aromatic hydrocarbons (PAHs) has been frequently performed in various sites, whereas that of chlorinated PAHs (ClPAHs) is limited. This study performed the time-resolved analysis of PAHs and ClPAHs in hourly PM2.5 spots collected using a tape filter at three stations in urban cities. The hourly concentrations of the total PAHs and ClPAHs exhibited specific variations in each station, attributable to the different sources and origins. According to PAH diagnostic ratio analysis, the hours at which the ClPAH concentrations were elevated showed the contributions of coal, petroleum combustions, and aged particles. The network analysis of the datasets was performed to visualize the association of each compound with the sampling time and station. PAHs were prevalent in all the stations at every time, whereas the impacts of ClPAHs were limited to certain stations and times. This suggests that the ClPAHs in the air could be attributed to specific sources, dissimilar to the ubiquitous sources of PAHs.