Why measure carbon monoxide?
Carbon monoxide is a colorless and odorless gas that blocks your blood?s ability to carry oxygen. Because of this, carbon monoxide exposure can be fatal at high doses. Various organizations have set acceptable upper limits for humans. People can breathe higher amounts for shorter times without a harmful effect, but people with heart or lung diseases will be more susceptible to poisoning. The U.S. Environmental Protection Agency (EPA) says that 35 parts per million (ppm) is safe for short periods, and that 1,000 ppm is cause for immediate evacuation of the area. Most home carbon monoxide alarms will start to go-off at about 100 ppm. EPA expects that levels of 9 ppm will be safe over the long term. The average level for most large cities is about 1 ppm. At the ConocoPhillips-Rodeo refinery, the maximum levels each month are about 1 ppm, which is about the same as in most cities in the United States. People who smoke cigarettes get carbon monoxide from the smoke, and they average about 35
