Abstract
In recent years, the concentrations of precursors of ozone have been decreasing in Japan, but the ground-level ozone concentrations tend to increase. During the summertime in the Kanto region, anthropogenic emission control in Japan is an important factor for decreasing the ozone concentration. In this study, we conducted an air quality simulation using WRF and CMAQ with the anthropogenic emissions data in 2000 and 2005 to verify the effect of the emission controls between 2000 and 2005 on the ozone concentration in the Kanto region. The NOx and VOC reductions contribute to the increase in the daytime maximum ozone in the central Tokyo surrounding area but to the decrease in the other areas of the Kanto region. For the NOx reduction case, the daytime maximum ozone was increased in a wide area of the plains. On the other hand, The VOC reduction effectively works to decrease the ozone concentration in the entire Kanto area. Based on the results of the ozone sensitive analysis for a high concentration day, the NOx sensitive and mixed sensitive regime account for half of the number of occurrences in inland Kanto area. Howeber, the VOC sensitive regime was the majority in the large city. These results show the effectiveness of the reduction of precursors to the decrease in the ozone concentration in each area of Kanto.
