Different industries have their own characteristics， so the gases that need to be used are different.

In the medical industry， there are some high-purity gases used for testing equipment， such as lung function gases， blood testing gases， anesthesia gases， anaerobic culture gases， aerobic culture gases， etc. Most of these gases are used by hospitals and some are used by medical equipment manufacturers， such as sterilization gases.

Most of the gases used in the environmental protection industry are toxic and harmful substances， such as sulfur dioxide， nitrogen oxides， hydrogen sulfide， carbonyl sulfide， carbon monoxide， etc.， while automobile exhaust is the most serious. With the increase in the number of automobiles， exhaust emissions have become the main source of pollution， and the main components of exhaust are carbon monoxide， nitric oxide， carbon dioxide， propane， etc.