Seasonal Change in the Atmospheric Concentration of Particulate Polycyclic Aromatic Hydrocarbons in Ho Chi Minh City, Vietnam

摘要

We analyzed atmospheric particulate polycyclic aromatic hydrocarbons (PAHs) in Ho Chi Minh City, Vietnam, for 19months. The average concentrations of total PAHs at dry and rainy seasons were 4.28 plus or minus 2.83 and 15.71 plus or minus 8.21ngm super(&# x2212; 3), respectively. The use of motorcycles without catalytic converters, estimated to be main emission sources of PAHs, would be higher during the dry season. PAH concentrations show a negative correlation with sunshine duration (r=-0.51). Furthermore, the ratio of average PAH concentration in the dry season to that in the rainy season shows a positive correlation with photolytic half-life (r=0.94). Thus, seasonal changes in PAH concentrations are attributable to their photolytic degradation.