Sensitive analytical method for particle-bound polycyclic aromatic hydrocarbons: A case study in Chiang Mai, Thailand
Using a MiniVol air sampler, respirable particulate matter (PM 10) was collected from 4 areas in Chiang Mai City. Concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in the PM10 samples were determined by extraction from a quartz fibre filter with acetonitrile using an ultrasonicator, before filtering and evaporating prior to GC-MS analysis. The mean 24 h PM10 levels in a suburban area, a community area, and two traffic-congested areas were found to be in the ranges 15-54 μg/m 3, 23-60 μg/m3, and 67-144 μg/m3, respectively. The mean total concentrations of the 16 PAHs in the PM 10 samples were in the ranges 2.7-8.4 ng/m3, 3.9-9.1 ng/m3, and 7.6-16.6 ng/m3, respectively. The amount of PM10 was fairly well correlated with particle-bound PAH concentrations. Temporal variation clearly affected the PM10 concentration but it was not so clear in the case of particle-bound PAHs. The average benzo(a)pyrene-equivalent carcinogenic power values showed that community areas had a better air quality than traffic-congested areas. The diagnostic ratios revealed that diesel engine emissions might be the main source of PAHs in the ambient air of these areas.
Chantara, S., Sangchan, W.
PAHs, PM10, air pollution, GC-MS, carcinogenic power