Understanding the Cause of Ozone Layer Depletion

The ozone layer is a vital part of Earth's stratosphere that absorbs most of the Sun's harmful ultraviolet (UV) radiation. Depletion of this layer leads to increased UV radiation reaching the Earth's surface, which can cause skin cancer, cataracts, and harm to ecosystems.

The primary cause of the depletion of the ozone layer has been identified as certain man-made chemicals. Among the options provided, one represents the most significant group of these chemicals.

Let's look at the options:

• F.F.C. - This acronym does not represent a known class of major ozone-depleting substances.
• F.C.C. - This acronym does not represent a known class of major ozone-depleting substances.
• C.C.F. - This acronym does not represent a known class of major ozone-depleting substances.
• C.F.C. - This acronym stands for Chlorofluorocarbons.

Chlorofluorocarbons, or CFCs, are organic compounds that contain carbon, fluorine, and chlorine atoms. They were widely used in various applications, including refrigerants, propellants in aerosol cans, solvents, and foam blowing agents. When these chemicals reach the stratosphere, they are broken down by intense UV radiation, releasing chlorine atoms. A single chlorine atom can catalyze the destruction of thousands of ozone ($\text{O}_3$) molecules, leading to the thinning of the ozone layer.

Due to their significant impact on ozone depletion, the production and use of CFCs have been largely phased out under international agreements like the Montreal Protocol.

Therefore, the cause for the depletion of the ozone layer is primarily attributed to Chlorofluorocarbons, represented by the acronym C.F.C.