Trees are cool, studies show. (News).

TRENTON, NJ -- Trees can significantly cool urban areas that generate heat and clean the air by absorbing pollution, according to two studies sponsored by the U.S. Environmental Protection Agency (EPA) and the New Jersey Department of Environmental Protection (DEP). The studies examined so-called "urban heat islands" surrounding the cities of Newark and Camden and explored various measures to mitigate their adverse effects.

On warm summer days, the air in urban areas can be significantly hotter than in surrounding areas--an effect called a "heat island." The problem is caused by a variety of factors that trap heat, including buildings and dark pavement that absorb the sun's rays rather than reflect them.

"These two cities generate unneeded heat, which is not only unpleasant, it can have real health consequences for urban residents and for the environment," said Jane M. Kenny, EPA Regional Administrator. "The good news is that there is a relatively simple and economical solution--plant trees."

Kenny added that while it can take five years or more for a newly planted tree to grow enough to begin significantly cooling the environment and absorbing pollution, the long-term benefits of trees are irrefutable.

The two studies--conducted by Montclair State University and National Aeronautics and Space Administration's Goddard Institute for Space Studies with research assistance from Columbia University--confirmed that both Newark and Camden have heat islands. ...