Environmental Science

Toward a Clear Day

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Science  23 Nov 2001:
Vol. 294, Issue 5547, pp. 1619
DOI: 10.1126/science.294.5547.1619c

On winter mornings in downtown Los Angeles it may be possible to see nearby snow-capped mountains—if there is little smog. In summer, a view of the mountains is even rarer. Reduced visibility is a common and convenient measure of air pollution, and the one used most often by locals. Because there are numerous sources of pollutants in a large city, it can be difficult to assess specific control efforts or to determine how best to combine them to minimize economic costs. Kleeman et al. use visibility as a measure of smog in a model of air pollution in Los Angeles to compare control efforts with respect to specific emission sources. An aggressive program of diverse emission controls could double visibility in Los Angeles and provide more frequent views of the surrounding peaks.—BH

Environ. Sci. Technol., 10.1021/es001865f.

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