Hydrofluoroalkane

Hydrofluoroalkane (HFA) is a class of hydrofluorocarbons consisting of carbon, hydrogen, and fluorine atoms, with no chlorine or bromine. HFAs are used as propellants in aerosol products and as solvents or blowing agents in various applications. They gained prominence as alternatives to ozone-depleting CFCs.

In medicine, HFAs are widely used as propellants in metered-dose inhalers (MDIs), enabling stable, fine aerosol particles that deliver medication to the lungs. Common formulations include HFA-134a (1,1,1,2-tetrafluoroethane) and HFA-227ea (1,1,1,2,3,3,3-heptafluoropropane).

Environmentally, HFAs have zero ozone depletion potential but can have high global warming potential (GWP) relative to CO2. Their use has prompted regulatory measures under international and national schemes to phase down high-GWP hydrofluorocarbons, and to encourage development of alternatives or reduced-propellant formulations.

Safety and use: HFAs are designed for pharmaceutical and consumer products and are generally considered safe at the small amounts inhaled from MDIs, though the health effects depend on the activity and the accompanying medication. Research continues into lower-GWP propellants and non-propellant delivery methods to reduce climate impact.