Air pollution emissions from motor vehicles have dropped considerably since 1970 - VOC emissions are down 73 percent, NOx emissions are down 41 percent, PM10 emissions are down 50 percent, and CO emissions are down 62 percent. This is due primarily to more stringent light-duty engine and fuel standards. These reductions have occurred despite a 41 percent increase in population, 167-percent growth in Gross Domestic Product (GDP), and 157-percent growth in Vehicle Miles Traveled (VMT).
Sources: U.S. Environmental Protection Agency. Average Annual Emissions, All Criteria Pollutants, Years Including 1980, 1985, 1989-2001. February 2003. Web site: http://www.epa.gov/ttn/chief/trends/, 28 June 2005.
U.S. Census Bureau. Selected Historical Census Data Population and Housing Counts, Population 1790-1990.
August 1993. Table 16, 26-27;
Web site: http://www.census.gov/population/censusdata/table-16.pdf, 28 June 2005.
U.S. Census Bureau. Time Series of National Population Estimates: April 1, 2000 to July 1, 2001. December 2004, Table 1.
Web site: http://www.census.gov/popest/data/historical/2000s/index.html, 28 June 2005.
U.S. Census Bureau. Statistical Abstract of the United States 2003, Table 587, February 2004.
Web site: http://www.census.gov/prod/2004pubs/03statab/labor.pdf, 28 June 2005.
Bureau of Economic Analysis. Survey of Current Business. Volume 83 No. 4. April 2003.
Web site: http://www.bea.gov/scb/toc/0403cont.htm, 28 June 2005.
Federal Highway Administration. Highway Statistics Summary to 1995. July 1997.
Web site: http://www.fhwa.dot.gov/ohim/summary95/index.html 29 June 2005.
Federal Highway Administration. Highway Statistics 2002. October 2003.
Web site: http://www.fhwa.dot.gov/policy/ohim/hs02/pdf/vm2.pdf, 28 June 2005.
*Note: Data for PM10 is not available through 1970.