A comparison of PM2.5 and PAHs in ambient air between an urban background site and a background site in Ho Chi Minh city

This study aims to evaluate the differences between PM2.5, PAHs concentration, PAHs species, and their gas/particle partitioning in an urban background site as opposed to another background site. Saigon zoo was selected as a representative of the urban background site (UBS), and the Can Gio mangrove reserve was selected as the other background site (BS). PM2.5 and gas and particle-phase PAHs samples were collected at the UBS between March 2017 and February 2018, while the samples were collected at the BS for one week in the dry season (April) and in the rainy season (October). The results demonstrated that both PM2.5 and PAHs concentrations at the UBS were significantly higher than those at the BS. The PM2.5 concentration at the UBS and BS ranged from 13.3 to 67.6 μg/m3 and from 5.1 to 22.7 μg/m3, respectively. The total concentration of 14 PAHs at the UBS was 2.6 times greater than that at BS. Phenanthrene (Phe) was the dominant PAH in ambient air at both sites. Benzo[g,h,i] perylene (BghiP) and Indeno[1, 2, 3-cd]pyrene (InP), which indicate the traffic source, accounted for 3.6 and 3.3% of total PAHs at the UBS, while that at the BS accounted for 1.5 and 1.3%, respectively. This result suggested that vehicular emission strongly affected the UBS site.