Carbon monoxide (CO) is a byproduct of incomplete combustion of fossil fuels. It is a colorless, odorless gas that is harmful to human health. One of the major contributors to elevated CO levels in the ambient air is automobile exhaust. Over the last 25 years, however, automobile manufacturers have increased the efficiency of the automobiles such that they produce 80-90% less CO.

The National Ambient Air Quality Standards (NAAQS) for carbon monoxide are a daily one hour average of 35 ppm (parts per million) and a daily 8 hour average of 9 ppm, not to be exceeded more than once a year.

Currently ARAQMD has two sites for monitoring CO, one located in downtown Akron and the other at Patterson Park in Akron.