Which gas is a major product of industrial production for use in aerosol propellants and air conditioning systems?

Freon-12 is a major product of industrial production for use in aerosol propellants and air conditioning systems. Freon-12, also known as Dichlorodifluoromethane (CCl2F2), is a type of chlorofluorocarbon (CFC). Though effective, Freon-12 was found to deplete the ozone layer, leading to its phasedown under the Montreal Protocol. Today, it's largely replaced by hydrofluorocarbons (HFCs), like R-134a, which are less harmful to the ozone layer but still contribute to global warming.