Measurements of gas and particle phase polycyclic aromatic hydrocarbons (PAHS) in Ho Chi Minh city in the period of 2017 to 2018

Abstract

This study was conducted to assess the distribution of polycyclic aromatic hydrocarbons (PAHs) between gas and particle phase in the ambient air in Ho Chi Minh City in the period of 2017 to 2018. Gas and particle phase PAHs samples were collected at five sites in Ho Chi Minh City in a period between March 2017 and February 2018. Particle phase PAHs were collected on glass fiber filters and gas phase PAHs were adsorbed on polyurethane foams (PUFs). Gas and particle phase PAHs were determined by using high-performance liquid chromatography method (HPLC-FLD). In the rainy season, the results shown that total PAHs concentrations in the gas phase was 43.16 ± 19.36 ng/m3 while that in the particle phase was 5.82 ± 3.96 ng/m3. In the dry season, total PAHs concentrations in the gas phase was 40.66 ± 15.14 ng/m3 and in the particle phase was 4.50 ± 2.54 ng/m3. The total concentration of 14 PAHs in the gas phase (42.08 ± 17.62 ng/m3) accounted for over 85% of the total concentration. High molecular weight PAHs (HMW-PAHs) had the highest concentration in the particle phase, accounting for about 78% of the total concentration of 14 PAHs. In contrast, in the gas phase, low molecular weight PAHs (LMW-PAHs) was dominated, accounting for over 65% of the total concentration of 14 PAHs. Particle fraction was obtained to understand the particle/gas phase partitioning of PAHs in ambient air in Ho Chi Minh City. Moreover, particle fraction and logPL0 have a non-linear correlation. Source apportionment of PAHs was carried out by using PMF model. The PMF results indicate four factors that affect PAHs concentrations in Ho Chi Minh City. In four factors, vehicular emission contributed strongly to PAHs concentrations.