Carbon monoxide emissions are produced from many different combustion processes and are especially common in automobile exhaust. Carbon monoxide is a scentless, invisible gas that is quite poisonous. It is also known to be a major environmental pollutant. A carbon monoxide molecule is made up of a single carbon atom joined to a single oxygen atom, as opposed to the more common carbon dioxide, which is also produced in combustion reactions and is made up of one carbon atom joined to two oxygen atoms. Carbon monoxide is produced in preference to carbon dioxide in many partial combustion reactions when there is a limited supply of oxygen.
Carbon monoxide emissions originate from a wide variety of residential, industrial, and transportation-related sources. Transportation is, by far, the number one source of carbon monoxide emissions. The incomplete combustion of hydrocarbons in internal combustion engines in automobiles is responsible for a significant amount of the carbon monoxide emitted into the air on a daily basis. Airplanes, boats, gasoline equipment, and diesel equipment also contribute a great deal to the amount of carbon monoxide in the air.
There are also many residential sources of carbon monoxide emissions. Furnaces, wood stoves, and gas heaters can all increase the household level of carbon monoxide. Water heaters, especially older ones, can and often do have the same effect. Tobacco smoke can also contain carbon monoxide. Car exhaust from automobiles in attached garages tend to increase the amount of household carbon monoxide, especially in the winter when people let their cars warm up for several minutes in the garage before driving them.
Many industrial plants produce a significant amount of carbon monoxide as a waste product. These carbon monoxide emissions are particularly common in steel plants, foundries, and oil refineries, since all involve processes that release the toxic gas as a waste product. Some chemical plants also produce carbon monoxide as a waste product, while others produce it for industrial use as it is used in some industrial processes.
Carbon monoxide emissions can lead to carbon monoxide poisoning, which can be fatal. The colorless, odorless nature of carbon monoxide makes it particularly hazardous as it is impossible to detect without some kind of carbon monoxide detector. Carbon monoxide is harmful because it reduces the delivery of oxygen to various vital organs in the body. Symptoms of carbon monoxide poisoning are often similar to flu symptoms: headache, nausea, dizziness, lethargy, and weakness. Other symptoms include confusion, disorientation, and visual disturbance.