大気二酸化炭素の酸素同位体比測定用の気体採取バッグによる試料採取 [in Japanese] Collection of atmospheric carbon dioxide by a gas sampling bag for its oxygen isotopic analysis [in Japanese]
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In order to examine feasibility of atmospheric carbon dioxide collection by a gas sampling plastic bag for oxygen isotopic analysis, progress of oxygen isotopic exchange between carbon dioxide and water vapor in air preserved in the bag were experimentally studied. In this study, an aluminum film intercalated plastic bag was used. The experiments were done under two different temperature conditions. In one case (samples C and D), condensation of water vapor happens, while not in the other case (samples A and B). Although the oxygen isotopic exchange progressed without regard to the condensation of water vapor in both cases, the rate of exchange is rather slow, and especially almost no exchange happens during early one or three days. This shows that the collection of air sample by the plastic bag is feasible and the oxygen isotopic ratios of CO<sub>2</sub> can be almost correctly measured, if the CO<sub>2</sub> is able to be separated from the bag within one or three days after the collection. For example, in a case of air samples collected in a tunnel of vehicle road, carbon and oxygen isotopic ratios of CO<sub>2</sub> showed a good mixing relationship of two kinds of CO<sub>2</sub> from automobile exhaust gas and ambient atmosphere.
Chikyukagaku 38(1), 11-16, 2004
The Geochemical Society of Japan