National Indicators:
Metropolitan Air Quality Nonattainment

Poor air quality can have significant adverse effects on human health, the built environment, and ecosystems, as well as on property values and recreational values. It is important to achieve and maintain good air quality if we are to ensure a healthy environment now and in the future.

From 1970 to 1990, increases in the Nation’s population and economic growth were accompanied by increasing air pollution. Over this period of time, emissions of nitrogen oxides increased by about 700%, emissions of volatile organic compounds increased by about 250%, and emissions of sulfur oxides increased by about 200%. Many of the things that contributed to air pollution--such as low-cost automobile fuel--also had important economic and societal benefits.

The good news is that since the passage of the Clean Air Act in 1970 (which required the industrial and automobile sectors to reduce emissions of air pollutants), the atmospheric concentrations of many air pollutants in the United States have been substantially reduced. The major exceptions are carbon monoxide and ground-level ozone, which continue to pose serious problems.

As indicated in Figure 4.39, in 1996, approximately 165 metropolitan areas still had unhealthy air, potentially affecting the health of 123 million people. However as indicated in Figure 4.40, there has been a substantial drop in the number of metropolitan areas not attaining air quality standards. In the context of sustainable development, the full economic, environmental, and social costs and benefits of further reducing air pollution must be considered.

Reference:

Council on Environmental Quality, Environmental Quality, 25^th Anniversary Report.

Link(s) to national databases (also see section on Related Internet Links):

• EPA Office of Air and Radiation: Air Quality.
• EPA Tools and Information