A new study suggests that cleaning up the air may help to feed the world.

Published in the November 23 issue of Proceedings of the National Academy of Sciences, the study found that heavy regional haze in China's most important agricultural areas may be cutting food production there by as much as one-third. Covering a million square kilometers or more, the haze scatters and absorbs solar radiation, reducing the amount of sunlight reaching key rice and winter wheat crops. That decreases plant growth and food production.

"For crops that are irrigated and fertilized, there is often a direct correlation between how much is grown and how much sunlight reaches those crops," said Dr. William L. Chameides, professor in the School of Earth & Atmospheric Sciences at the Georgia Institute of Technology. "In China there is a significant amount of haze that reduces the sunlight reaching the surface by at least five percent, and perhaps as much as 30 percent. The optimal yields of crops in China are likely reduced by the same percentage."

Chameides says the NASA-funded study provides China -- and other nations with similar issues -- another option in the struggle to feed their growing populations. It is believed to be the first work quantitatively to assess the direct impact of regional haze on the yields of these crops.

"China is already losing 10, 20 or even 30 percent of its crop production to haze," he said. "Controlling the sources of the haze represents a potential way to increase crop production because the technology exists to control air pollution."

The estimates of crop production losses are based on detailed long-term measurements at Nanjing, 200 miles southwest of Shanghai, but are extrapolated to other areas
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Contact: John Toon
john.toon@edi.gatech.edu
404-894-6986
Georgia Institute of Technology Research News
5-Dec-1999