Abstract
The Air Pollution Control Act was revised in April, 2006, and a new emission regulation for VOC was started for the purpose of photochemical oxidant reduction. The analysis showed that the reduction of VOC emissions in Kanto influenced the generation of photochemical oxidants in the ambient air. The VOC emissions have shown a tendency to decrease since 2000, and each material group (hydrocarbons, alcohols, etc.) has equally decreased without changing its composition ratio. However, the composition ratio of the individual components in every group significantly changed from 2000 to 2010. Using the data from the sites with photochemical oxidant concentrations over 120 ppb, the excess annual integrated concentrations were calculated and the influence that a change in the annual VOC emissions had on the generation of the highly concentrated photochemical oxidants was analyzed. Additionally, we normalized them by the temperature unit (℃) and solar radiation unit (MJ/m2) , and calculated the correlation coefficients between the decrease in the normalized value and reduction in the VOC emission since 2005 to 2010 by the prefecture. As a result, the data from Tokyo, Kanagawa and Saitama indicated high correlation coefficients, and it was deduced that the reduction in the VOC emissions reduced the high concentration of the photochemical oxidants in these prefectures.
