LAUSR

Abstract Chlorinated polycyclic aromatic hydrocarbons (ClPAHs) are recognized as ubiquitous hazardous pollutants in the environment, whereas their behavior in local areas remains unclear. Additionally, there is limited information on the sources in local areas. Here, we investigated the seasonal trends of ClPAHs associated with fine particles (PM2.5) at two sites near heavy traffic roads to evaluate the local atmospheric behaviors and sources. The annual mean concentrations of total ClPAHs at the north (site A) and south side (site B) across a heavy traffic road were 12.0 and 19.2 pg/m3, respectively. The higher concentration at site B was further emphasized during the winter season; at that time the site was located beneath the wind from the traffic road. In addition, for individual ClPAHs, the behaviors of 8-chlorofluoranthene (8-ClFluor) and 7-chlorobenz[a]anthracene (7-ClBaA) were consistent with the frequency of the north wind, suggesting that 8-ClFluor and 7-ClBaA have the ability to be indicators of vehicle exhaust. Diagnostic ratios using these specific ClPAHs during high-traffic activities provided the specific values to differentiate the impacts.