the areas with the worst ozone levels are usually not within the city but are immediately downwind of the city because ozone is formed relatively slowly by the action of sunlight on oxides of nitrogen and hydrocarbons.

Urban sprawl also creates water availability and water pollution issues. Suburban development has an impact on groundwater availability because in suburban areas water from rain and other precipitation is moved off the land and immediately enters rivers; thus, the groundwater does not get recharged appropriately. That is, the water rapidly enters the rivers instead of circulating through the ground until it eventually reaches the river. Also, water draining right off a parking lot may create storm water and sewage overflows.

Other problems in suburbia include the presence of optimal conditions for the transmission of Lyme disease and mosquito-borne disorders because of the interface between mosquitoes and humans.

Other health problems due to urban sprawl include heat islands, global climate change, noise, a lack of availability of healthy food choices, public health workforce issues, and safety issues such as crime and traffic. When a green area is replaced by asphalt, a bigger heat island results in changes in local temperatures and ecosystems. Heat island and temperature changes also affect the rural areas that are near the suburbs, noted Goldstein.

Attempts to try to understand the impact of urban sprawl on the public health workforce are beginning. The workforce is decreasing and the resources are diminishing at a time when the public health system is encountering some of its greatest challenges, said Goldstein. Furthermore, a large turnover of the public health workforce is anticipated because of retirement. The impact is different in different areas, but often the public health workforce in the rapidly growing suburban areas has less expertise because the budget for the public health infrastructure cannot keep up with the growth, noted Goldstein.

Is Europe the Answer?

Europeans have done an excellent job of keeping their cities and rural areas separate, said Goldstein. The Europeans protect their rural agricultural land and enforce their zoning laws rigidly, making it more difficult to build out from the existing areas of the community. European zoning laws encourage populations to be dense in urban areas by promoting the use of mass transit and the development of bikeways and walkways and by reducing the need for cars.

In Europe, political power and budgets are centralized. In almost every Western European country, its capital is also its largest and most powerful city. This is almost never true in U.S. states, as Americans culturally have less trust in the centralization of power, said Goldstein. The United States has a municipality or some governmental organization for every 3,500 citizens. Most of the local funding in the United States is derived locally, whereas most of the local funding in



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement