What environmental issue is associated with older refrigerants like CFCs?

Older refrigerants like chlorofluorocarbons (CFCs) are primarily associated with ozone depletion. When CFCs are released into the atmosphere, they rise and eventually break down in the stratosphere due to ultraviolet (UV) radiation. This process releases chlorine molecules, which can then react with ozone (O3) molecules, leading to the depletion of the ozone layer. The ozone layer is critical for blocking harmful UV radiation from the sun, and its reduction has significant implications for environmental and human health, including increased risks of skin cancer and harm to ecosystems.

While air pollution, water contamination, and global warming are important environmental concerns, they do not directly relate to the specific impact of CFCs. Understanding the effects of refrigerants on the ozone layer has led to international efforts like the Montreal Protocol aimed at phasing out the production and use of ozone-depleting substances.