Carbon Monoxide Exposure

Trends in U.S. Air CO Levels:

Figure 3-6. Composite average of the annual second highest 8 hr. Carbon Monoxide concentrations for rural, suburban, and urban sites, 1988 - 1997.

Source: EPA. Air Quality Criteria for Carbon Monoxide, National Center for Environmental Assessment, 2000

...... last changed 06/01/04

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