301 自動車から排出される二酸化炭素の安定炭素同位体比(大気・水環境評価技術(1))

Abstract

Stable carbon isotope ratios of carbon dioxide (CO_2) in gasoline-, diesel- and natural gas-fueled automobiles exhaust were measured after catalyst treatment device using a near-IR laser based spectrometer. In the case of gasoline-fueled automobiles, CO_2 stable carbon isotope ratios were measured before catalyst treatment device. CO_2 concentration and CO_2 stable carbon isotope ratios in gasoline-fueled automobile exhaust were changed in accordance with the driving conditions. The variations of them were found to be due to the oxidation of carbon monoxide and hydrocarbons, and the difference of the reactivity of stable carbon isotopes on the catalyst treatment device. We also found that there were differences between CO_2 stable carbon isotope ratios in the gasoline-, diesel-fueled automobiles exhaust and those in the natural gas-fueled automobile exhaust.