Figure 5-9 - Modal Shares of Key Criteria Pollutants from Transportation Sources: 1997
Figure 5-9 - Modal Shares of Key Criteria Pollutants from Transportation Sources: 1997

KEY: CO = carbon monoxide; NOX = nitrogen oxides; PM-10 = particulate matter 10 microns in diameter or smaller; VOC = volatile organic compounds.
NOTES: Other nonroad includes 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 and Radiation, Air Quality Planning and Standards, National Air Pollution Emission Trends, 1990-1997, available on the EPA website at www.epa/ttn/chief/trends97/emtrnd.html.