Carbon monoxide (CO) is a colorless, Odorless gas that at very low concentrations is extremely toxic to humans and other animals. The high toxicity resultsfrom a striking physiological etfect, namely, that carbon monoxide and hemoglobin in blood have a strong natural attraction for one another. Hemoglobin in our blood will take up carbon monoxide nearly 250 times more rapidly than it will oxygen.Therefore, if there 1s any carbon monoxide in the vicinity, a person will take it in very readily, with potentially dire effects. Many people have been accidentally asphyxiated by carbon monoxide produced from incomplete combustion of fuels in campers, tents, and houses. The effects depend on the dose or concentration of exposure and range from dizziness and headaçhes to death. Carbon monoxide is particularly hazardous to people with known heart disease, anemia, or respiratory disease. In addition, it may cause birth defects, including mental retardation and impairment of growth of the fetus. Finally, the effects of carbon monoxide tend to be worse at higher altitudes, where oxygen levels are naturally lower.
Approximately, 90% of the carbon monoxide in the atmosphere comes from natural sources, and the other 10% comes mainly from fires, automobiles, and other sources of incomplete burning of organic Compounds. Concentrations of carbon monoxide can build up and cause serious health effects in a localized area.