大気中の粒子状多環芳香族炭化水素類の濃度変動とその関連要因

抄録

In the present study, variations in daily PAH concentrations were investigated in relation to meteorological data and concentrations of other air pollutants in order to verify the effectiveness of the current estimation method. From January 2000 to March 2001, airborne particulates were collected at one site in Okayama, Japan, for 24 h on 7 days each month using a high-volume air sampler equipped with a quartz-fiber filter. The sampling site is in a rural area; however, because the Mizushima industrial zone is located about 15 km southwest of the sampling site and national highway 2 is located about 5 km north of the sampling site, the site usually has high PAH concentrations. From the 105 samples obtained at the sampling site, 23 kinds of PAHs were measured by the gas chromatography/mass spectroscopy (GC/MS) method, and the daily concentrations of 16 out of the 23 kinds of PAHs in air were obtained. As a result, large differences in daily total PAH concentrations, which ranged from 0.69 to 83 ng/m³, were observed at the sampling site. This result suggested that the current estimation method was ineffective. For example, there is a possibility of higher health risks being overlooked if the PAH concentrations are not measured on days on which the concentrations are high. Investigations of the relationship between PAH concentration and meteorological data such as wind direction and wind velocity revealed that the PAH concentrations were significantly and positively correlated with the number of hours per day of southwest wind and that the PAH concentrations were significantly and negatively correlated with the average wind velocity. This result implies that the PAH concentrations in air will be influenced by the Mizushima industrial zone, and that the PAH concentrations will be high on days experiencing southwest wind and low wind velocity at the sampling site.