Air quality effects of urban trees and parks

Abstract

Parks are significant parts of the urban landscape and comprise about 6% of city and town areas in the conterminous United States. These urban parks are estimated to contain about 370 million trees with a structural value of approximately $300 billion. The number of park trees varies by region of the country, but they can produce significant air quality effects in and near parks, related to air temperatures, air pollution, ultraviolet radiation, and carbon dioxide (a dominant greenhouse gas related to global climate change). Additional open space and other vacant lands in cities, which may contain trees and other vegetation, contribute significant additional benefits. Effects of parks and open space at the city scale can vary significantly depending on the amount of parkland and amount of tree cover within the parkland.