Carbon Monoxide Exposure
Trends in U.S. Air CO Levels:
Figure 3-7. Diurnal variation of nationwide composite hourly average Carbon Monoxide concentrations for winter (December to February), 1987 - 1996.
Source: EPA. Air Quality Criteria for Carbon Monoxide, National Center for Environmental Assessment, 2000
...... last changed 06/01/04
Back to COHQ Main Index