Simulations

The chapter began with a survey of major air pollutants, which include sulfur compounds, nitrogen oxides, ozone, carbon monoxide, volatile organic compounds, heavy metals, and particulate matter. Air quality indoors may be compromised by a number of pollutants contained in building materials, furniture, paint, cleaning materials and insecticides, as well as second-hand smoke.

Temperature, in particular the atmosphere's vertical temperature profile at a locale, greatly affects the dispersion of pollutants from their sources. When the environmental air temperature increases upward, a condition known as a temperature inversion, the air is stable and little vertical mixing occurs. In contrast, when the environmental air temperature cools rapidly with height, vertical mixing is vigorous.

Winds are important dispersers of air pollutants. However, while winds may bring relief to locales close to the pollution source, they may cause pollution problems elsewhere. The transport of sulfur compounds from sources in the Midwest to the Northeast and eastern Canada is an example.

Topography also shapes the dispersal of air pollutants. The pollution-prone Los Angeles basin, flanked by mountains to the east and cool water to the west, is a prime example. The Clean Air Act, enacted in 1970 and updated in 1990, has served as an important tool in the struggle to improve air quality in the U.S. The EPA, which was created in 1970, sets air quality standards, monitors pollution levels, and seeks compliance of violators.

Acid deposition, mainly the result of SO₂ and NO_x emissions, is a serious environmental and health problem in many cities and over much of the eastern United States and Canada. Some slight improvement has been noted recently, but the problem is far from solved.

Simulation 1 (969.0K)

Simulation 2 (463.0K)