Figure 2 - Modal Share of Key Transportation-Related Air Pollutants: 1998
Figure 2 - Modal Share of Key Transportation-Related Air Pollutants: 1998

KEY: CO = carbon monoxide; NOx = nitrogen oxides; VOC = volatile organic compounds; PM-10 = particulate matter 10 microns in diameter or smaller.
NOTE: Other nonroad includes gasoline and diesel recreational vehicles, recreational marine vessels, airport service vehicles, and railroad maintenance equipment. Does not include farm, construction, industrial, logging, light commercial, and lawn and garden equipment.
SOURCE: U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, National Air Pollutant Emission Trends: 19001998, EPA 454/R-00-002 (Research Triangle Park, NC:March 2000), also available at http://www.epa.gov/ttn/chief/trends/, as of May 18, 2001.