Carbon monoxide is one of the six common air pollutants identified by the EPA as being critical to assessing the environmental health of a place. Carbon monoxide largely comes from automobile and industrial emissions and is potentially life-threatening to life forms that breathe air. It enters the body through the lungs and deprives the body of oxygen. High concentrations of carbon monoxide in the blood can weaken heart contractions and lower the volume of blood distributed throughout the body (RESPONSIVENESS SUMMARY to Testimony Taken at the Ozone Oral Proceeding and Written Comments Received on the Serious Area Ozone State Implementation Plan for Maricopa County, p. 2).
Ozone data for Maricopa County comes from the U.S. Environmental Protection Agency's Monitor Trends Report - Criteria Air Pollutants for Maricopa County, AZ. It was collected by the Decision Center for a Desert City (DCDC) in February, 2009.