Angie's LIST Guide to
Carbon monoxide

Carbon monoxide is a compound created when one carbon atom and one oxygen atom combine. It is formed naturally as a result of photochemical reactions in the lower part of the earth’s atmosphere and as a result of the combustion that occurs in volcanic eruptions and forest fires.

In nature, carbon monoxide typically is a short-lived compound as it is readily converted into carbon dioxide and ozone. It can be toxic to humans and animals in large doses and can cause significant symptoms even at low rates of exposure.

Carbon monoxide is colorless and odorless and produces few distinguishable physical symptoms before reaching toxic levels within the body; as a result, carbon monoxide poisoning is often overlooked or misdiagnosed, making it difficult to obtain an accurate assessment of the scale of the problem. In addition, carbon monoxide is only slightly lighter than air and easily mixes with the ambient air inside the home, making it even more difficult to pinpoint the source of carbon monoxide toxicity.

According to a report by the Centers for Disease Control and Prevention, carbon monoxide exposure results in about 500 deaths and 15,000 emergency room visits in the U.S. each year. People in weakened conditions or in ill health, elderly individuals and children are among the most vulnerable to the effects of carbon monoxide and may show signs of exposure before they are present in healthy adults.

Symptoms vary depending on the concentration of carbon monoxide in the air and the duration of exposure, but headache, dizziness and nausea are typical in the early stages. Even at slight concentrations of 35 ppm, headaches and dizziness can occur with constant exposure.

At high rates of exposure of 12,800 ppm or more, acute poisoning results within seconds and death can occur within three minutes of the time of exposure. Symptoms of moderate exposure include cardiac arrest or arrhythmia, seizures, low blood pressure, loss of consciousness and other symptoms involving the respiratory, circulatory and central nervous system. For patients who experience long term, low-grade exposure to carbon monoxide as a result of faulty equipment or venting within the home, the long-term effects can include serious neurological dysfunctions, short and long-term memory loss and depression.