Consider the following: 1. Aerosols 2. Foam agents 3. Fire retardants 4. Lubricants In the making of how many of the above are hydrofluorocarbons used?

Answer: C. Hydrofluorocarbons (HFCs) are used in three of the four (aerosols, foam agents, fire retardants); lubricants typically do not use HFCs. HFCs are synthetic chemicals introduced as replacements for ozone-depleting CFCs and HCFCs under the Montreal Protocol. Major uses: (1) Aerosols: YES. HFC-134a and others used as propellants in metered-dose inhalers and aerosol sprays. (2) Foam agents: YES. HFCs serve as blowing agents in polyurethane and other rigid/flexible foams used in insulation and packaging. (3) Fire retardants: YES. HFCs (notably HFC-227ea/FM-200, HFC-23) are used in clean-agent fire suppression systems for data centres and museums. (4) Lubricants: NO. Lubricants are typically mineral oils, synthetic esters, polyalphaolefins (PAOs) or PFPEs. HFCs are gases and do not function as lubricant base stocks. So 3 of 4 (rows 1, 2, 3). Source: Kigali Amendment to Montreal Protocol / Ministry of Environment HFC phase-down notifications.