|People affected (thousands)||Percent of U.S. resident population||U.S. resident population (millions)|
NOTES: Noise-level contours are graphical representations of noise levels on a map, similar to elevation contours on a topgraphic map. Noise-level contours are lines that join points of equal sound levels. Areas between given noise-level contour lines would have a noise level between the two contour values. The U.S. Department of Transportation, Federal Aviation Administration has identified DNL 65 dB as the highest threshold of airport noise exposure that is normally compatible with indoor and outdoor activity associated with a variety of land uses, including residential, recreational, schools, and hospitals. Estimates are for areas surrounding airport property of 250 of the largest civil airports with jet operations in the United States. They exclude exposure to aircraft noise within an airport boundary.
SOURCES: Exposure: Federal Aviation Administration, Population: United States Census Bureau, as cited in U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau of Transportation Statistics, National Transportation Statistics, table 4-53, available at http://www.bts.gov/publications/national_transportation_statistics as of October 2008.