it is a colorless, odorless gas, special caution must be taken around methane. Ethane is also extremely flammable, explosive, and dangerous to inhale. Both of them may cause suffocation. Propane, too, is flammable and explosive, and may cause drowsiness or unconsciousness if inhaled. Butane presents the same hazards as propane. Alkanes also pose a threat to the environment. Branched alkanes have a lower biodegradability than unbranched alkanes. Methane is considered to be the greenhouse gas that is most dangerous to the environment, although the amount of methane in the atmosphere is relatively low. As of April, 2022, atmospheric methane concentrations were around 1910 ppb. See also Alkene Alkyne Cycloalkane Higher alkanes Aliphatic compound References Further reading Virtual Textbook of Organic Chemistry A visualization of the crystal structures of alkanes up to nonan Hydrocarbons