carbon dioxide is emitted as part of both plant and human respiration. Once carbon dioxide is released it quickly mixes into the atmosphere. Despite humanity’s hand in creating more CO2, this is a naturally occurring gas and is part of the environment.
Carbon monoxide is created from incomplete combustion which is a result of limited air supply. When only half as much oxygen is added to carbon, CO is formed. Fuel-burning appliances, including gas furnaces, gas stoves, gas dryers, gas water heaters, fireplaces, and cars are all industrial activities which create CO.