Comparing Metro Phoenix
Carbon Monoxide
Description: Carbon Monoxide (CO) is one of the criteria air pollutants identified by the EPA as being critical to assessing the environmental health of a place. The primary source of CO is motor vehicle exhaust predominantly from on-highway driving.
Rationale: Carbon monoxide impacts blood oxygenation, to the extent that people can become impaired and unable to perceive or perform tasks. It also complicates the health of persons with cardiovascular diseases. The average 2nd maximum 8-hour concentration levels are identified in the graphs. The National Standard for this criteria pollutant is 9.0 parts per million (ppm). Phoenix is the only city that had a level that exceeded this standard in 1996. Since then, Phoenix and all of the other comparator cities register levels below the standard. All of the cities in this comparison are currently in attainment for CO. Phoenix was previously listed as being in non-attainment, but was reclassified in 2005. Other cities that reached attainment status after being in non-attainment are Salt Lake City (1999), San Diego (1998), San Jose (1998), Seattle (1996), Portland (1997), Raleigh (1995), and Denver (2001). The remaining cities (Austin and Atlanta) have no reported record of being in nonattainment.
Source: Decision Center for a Desert City (DCDC) using records from the U.S. Environmental Protection Agency's Monitor Trends Report - Criteria Air Pollutants. For additional information on attainment status, refer to the EPA Greenbook, available online at http://www.epa.gov/oar/oaqps/greenbk/astate.html and http://www.epa.gov/oar/oaqps/greenbk/cfstate2.html.
