That's green as in grass, flowers and other plants. The city environment department plans to plant gardens atop several city buildings this summer as part of a U.S. Environmental Protection Agency program studying ways to help cool cities and reduce smog. We want to dress the city in lighter colors. Hotter temperatures increase smog by forcing electric plants to work harder and emit more pollution, city and EPA officials said.
Pollution reacts with heat and sunlight to create smog.
That's a big issue for Chicago, which consistently violates federal air quality standards. The rooftop gardens could begin with City Hall and other public buildings, such as schools, said Alexandra Holt, deputy director of the environment department. The first gardens could be planted this year. The city also will plant trees and other vegetation in medians to help cool pavement, and will consider light-colored paving surfaces, she said. Nobody knows how many roofs would have to be resurfaced or trees planted to make a measurable difference in heat and smog, said Virginia Gorsevski, program analyst with the EPA's office of air and radiation.