carbon monoxide (CO)

A trace gas present in the atmosphere, produced by the incomplete combustion of petroleum derivatives, wood, tobacco, and oils. It is a colorless, odorless gas with high toxicity. It causes death when breathed in high concentrations. It is one of the main polluting gases in large cities, being constantly monitored by air quality monitoring networks. Its concentration is measured in parts per million (ppm). Prolonged exposure to CO levels of between 1 and 70 ppm poses no health problem, but above 70 ppm symptoms such as fatigue, headache, and nausea begin to be experienced. From 150 to 200 ppm, the risk of death from inhaling air contaminated with this gas is very high.