Changes in Urban Landscape Can Cut Smog

Funded by the U.S. Environmental Protection Agency, the study used aerial photographs taken with infrared cameras to make temperature maps; the images showed that rooftops and blacktops were the hottest areas in a city, while parks were the coolest. Preliminary releases indicate that on a hot day, the population center of the county is 1 to 2 degrees hotter than less-developed areas. As increased temperatures speed the formation of smog, lowered temperatures would decrease the amount of smog produced. The study calculated that doubling the number of trees along with cooling roof and pavement surfaces would result in a temperature drop of 2 to 3 degrees, and cause a 6 to 8 percent drop in ozone levels.