Carbon-14, tree rings,and urban air pollution |
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Authors: | William F Cain |
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Institution: | Loyola Marymount University, Los Angeles, California 90045, USA |
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Abstract: | Differences in natural 14C content of rings from trees from urban and rural locations have been compared on a year by year basis. The differences as a fraction of the urban tree's radioactivity reflect the local excess 14C-free carbon dioxide from fossil fuel combustion in the urban environment. New York City, Boston, and Washington, D.C., show different degrees of excess carbon dioxide. New York City averages about 6% excess carbon dioxide between 1950 and 1970. From this is infered an average carbon monoxide concentration during this period of 5 ppm. |
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