Chlorofluorocarbons (CFC) are gases that are commonly used as coolants in refrigerators and air conditioners, propellants In aerosol cans, and in plastic foams. These chemicals accumulate in the upper atmosphere and react with ozone (O3) in the presence of light. During these reactions, ozone is converted to ordinary oxygen (O2).
Ozone forms a layer in the upper atmosphere. This layer acts as a shield that prevents most of the ultraviolet radiation in sunlight from reaching earth's surface.
In recent years, reports from atmospheric research satellites indicate that the ozone layer is being depleted faster than it can be regenerated naturally. A thinning ozone layer means that more ultraviolet radiation is reaching the earth surface. This posses a danger to all living organisms. It may
• kill useful micro organisms;
• affect the growth of phytoplanktons , the important producers of the ocean food chains, and thus decrease an important human food source; and
• interfere with photosynthesis resulting in lower crop yields.
In humans, increased ultraviolet radiation may cause
• cataracts to develop, clouding the eye lens and resulting in blurred vision;
• severe sunburns;
• the appearance of various forms of skin cancer;
• the skin to age and wrinkle more rapidly; and
• a lowered resistance to infectious diseases.
