Which of the following best describes how the Montreal Protocol addressed ozone-depleting substances?

• A. Phased out production of ozone-depleting substances and mandated safer substitutes.
• B. Encouraged increased use of CFCs with new refrigerants.
• C. Banned all aerosols worldwide.
• D. Promoted the use of chlorine-containing solvents to speed up ozone recovery.

Answer: (A)

The Montreal Protocol works by phasing out the production and consumption of substances that deplete the ozone layer and by mandating safer substitute chemicals and technologies. It focuses on chemicals that release chlorine and bromine in the stratosphere—such as CFCs, halons, and related solvents—and it sets timelines for richer and poorer countries to reduce and eventually stop using these substances, while encouraging alternatives. This structured, phasedown approach has driven a global shift toward ozone-friendly choices and, over time, allowed the ozone layer to begin recovering as these harmful chemicals disappear from use.

This aligns with the idea that the protocol achieves its goal by eliminating ozone-depleting substances and guiding replacement products, rather than promoting more ozone-depleting chemicals or banning every aerosol or solvent.