In 16 of the 23 cities surveyed by the Trust for Public Land in 1993, residents of affluent neighborhoods had much better access to parks than their low-income counterparts. In Chicago, for example, there are 41 acres of park for every 1000 residents in the downtown Loop district but just one-half an acre per 1000 residents on its the Lower West Side. Take the Urban Heat Island Effect, for example. During the day, buildings, pavement and other urban surfaces absorb solar heat and release it as heat radiation, making temperatures in urban areas often two to four degrees higher than outlying areas. Trees can mitigate this effect, making urban areas more comfortable and reducing cooling bills.
Green space can also enhance air and water quality.
One acre of trees absorbs as much carbon dioxide as a car produces in 26,000 miles. Trees also absorb water during rain showers, reducing peak stormwater runoff by between 10 and 20 percent, according to the US Forest Service. The Federal Government provides some support to urban green space enhancement. More than a dozen cities receive HUD's Community Development Block Grants for garden programs. But these programs are small compared to recent state and local measures and planned Federal initiatives.