carbon monoxide, chemical compound, CO, a colorless, odorless, tasteless, extremely poisonous gas that is less dense than air under ordinary conditions. It is very slightly soluble in water and burns in air with a characteristic blue flame, producing carbon dioxide; it is a component of producer gas producer gas, fuel gas consisting chiefly of carbon monoxide and nitrogen. It is prepared in a furnace or generator in which air is forced upward through a burning fuel of coal or coke. Although the fuel is introduced through the top, no air is admitted there.
..... Click the link for more information. and water gas water gas, colorless poisonous gas that burns with an intensely hot, bluish (nearly colorless) flame. The gas is a mixture of carbon monoxide and hydrogen with very small amounts of other gases, e.g., carbon dioxide, and is almost entirely combustible as a result.
..... Click the link for more information. , which are widely used artificial fuels. It is a reducing agent, removing oxygen from many compounds and is used in the reduction of metals, e.g., iron iron, metallic chemical element; symbol Fe [Lat. ferrum]; at. no. 26; at. wt. 55.847; m.p. about 1,535°C;; b.p. about 2,750°C;; sp. gr. 7.87 at 20°C;; valence +2, +3, +4, or +6. Iron is biologically significant.
..... Click the link for more information. (see blast furnace blast furnace, structure used chiefly in smelting . The principle involved in this means of extracting metals is that of the reduction of the ores by the action of carbon monoxide, i.e., the removal of oxygen from the metal oxide in order to obtain the metal.
..... Click the link for more information. ), from their ores. At high pressures and elevated temperatures it reacts with hydrogen in the presence of a catalyst to form methanol methanol, methyl alcohol, or wood alcohol, CH₃OH, a colorless, flammable liquid that is miscible with water in all proportions. Methanol is a monohydric alcohol . It melts at −97.
..... Click the link for more information. . Carbon monoxide is formed by combustion of carbon in oxygen at high temperatures when there is an excess of carbon. It is also formed (with oxygen) by decomposition of carbon dioxide at very high temperatures (above 2,000°C;). It is present in the exhaust of internal-combustion engines (e.g., in automobiles) and is generated in coal stoves, furnaces, and gas appliances that do not get enough air (because of a faulty draft or for other reasons).

Carbon monoxide is an extremely poisonous gas. Breathing air that contains as little as 0.1% carbon monoxide by volume can be fatal; a concentration of about 1% can cause death within a few minutes. The gas is especially dangerous because it is not easily detected by human senses. Early symptoms of carbon monoxide poisoning include drowsiness and headache, followed by unconsciousness, respiratory failure, and death. First aid for a victim of carbon monoxide poisoning requires access to fresh air; administration of artificial respiration artificial respiration, any measure that causes air to flow in and out of a person's lungs when natural breathing is inadequate or ceases, as in respiratory paralysis, drowning, electric shock, choking, gas or smoke inhalation, or poisoning.
..... Click the link for more information. and, if available, oxygen; and, as soon as possible, expert medical attention. When carbon monoxide is inhaled, it reacts with hemoglobin, the red blood pigment that normally carries oxygen to all parts of the body. Because carbon monoxide is attracted to the hemoglobin about 210 times as strongly as is oxygen, it takes the place of oxygen in the blood, causing oxygen starvation throughout the body. Carbon monoxide detectors for homes are now readily available.

Carbon monoxide from automobile and industrial emissions is a dangerous pollutant that may contribute to the greenhouse effect and global warming global warming, the gradual increase of the temperature of the earth's lower atmosphere as a result of the increase in greenhouse gases since the Industrial Revolution .
..... Click the link for more information. . In urban areas carbon monoxide, along with aldehydes, react photochemically to produce peroxy radicals. Peroxy radicals react with nitrogen oxide to increase the ratio of NO₂ to NO, which reduces the quantity of NO that is available to react with ozone (see smog smog (smŏg) [smoke+fog], dense, visible air pollution . Smog is commonly of two types.
..... Click the link for more information. ). Carbon monoxide is also a constituent of tobacco smoke.

carbon monoxide

Inorganic compound, a highly toxic, colourless, odourless, flammable gas, chemical formula CO. It is produced when carbon (including coal and coke) or carbon-containing fuel (including petroleum hydrocarbons; e.g., gasoline, fuel oil) does not burn completely to carbon dioxide, because of insufficient oxygen. CO is present in the exhaust gases of internal combustion engines and furnaces. It is toxic because it binds to hemoglobin in blood much more strongly than does oxygen and thus interferes with transport of oxygen from lungs to tissues (see hypoxia; respiration). Symptoms of CO poisoning range from headache, nausea, and syncope to coma, weak pulse, respiratory failure, and death. CO is used industrially as a fuel and in synthesis of numerous organic compounds, including methanol, ethylene, and aldehydes.