• The contribution of mobile-source emissions to air pollution varies from area to area. Ambient concentrations of pollutants depend on several factors, such as the relative mix of sources, the extent of pollutant transport, the meteorology, and the topography of the area. The result is that different levels of controls on mobile and nonmobile sources are typically required for different areas in the Unites States.

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