Abstract
The relationship between the composition of volatile organic compounds (VOC) and the high concentration phenomenon of a photochemical oxidant (Ox) in Saitama Prefecture was examined. Characteristics of the VOC composition depending on time and season were developed for the windward and leeward sites in Saitama. The high concentration components were alkanes and aromatics but the components with a high ozone formation potential were alkenes, aromatics and aldehydes. The main substances, which contribute to the ozone formation, were ethylene, propylene, butene, toluene, xylene, ethylbenzene, formaldehyde and acetaldehyde. Concerning the time variation, the VOC supply in the daytime seemed to be related to the high Ox concentration, and it was particularly suggested that the high VOC concentration in the prefecture's southern area in the daytime influenced the high Ox concentration in the northern area. In addition, the aldehyde concentration rose in the daytime in any season, especially in the summer. Also, the concentration variation was similar to Ox. It was shown that the photochemical reaction forms aldehydes, and it was considered that aldehydes strongly contribute to the Ox formation.
