B.C. Air Quality

The Impacts of Ozone Depletion

Stratospheric ozone filters out most of the sun's potentially harmful shortwave ultraviolet (UV) radiation. If this ozone becomes depleted, then more UV rays will reach the earth. Exposure to higher amounts of UV radiation could have serious impacts on human beings, animals and plants, such as the following:

  • Harm to human health:
    • More skin cancers, sunburns and premature aging of the skin.
    • More cataracts, blindness and other eye diseases: UV radiation can damage several parts of the eye, including the lens, cornea, retina and conjunctiva.
    • Cataracts (a clouding of the lens) are the major cause of blindness in the world. A sustained 10% thinning of the ozone layer is expected to result in almost two million new cases of cataracts per year, globally (Environment Canada, 1993).
    • Weakening of the human immune system (immunosuppression). Early findings suggest that too much UV radiation can suppress the human immune system, which may play a role in the development of skin cancer.

  • Adverse impacts on agriculture, forestry and natural ecosystems:
    • Several of the world's major crop species are particularly vulnerable to increased UV, resulting in reduced growth, photosynthesis and flowering. These species include wheat, rice, barley, oats, corn, soybeans, peas, tomatoes, cucumbers, cauliflower, broccoli and carrots.
    • The effect of ozone depletion on the Canadian agricultural sector could be significant.
    • Only a few commercially important trees have been tested for UV (UV-B) sensitivity, but early results suggest that plant growth, especially in seedlings, is harmed by more intense UV radiation.
  • Damage to marine life:
    • In particular, plankton (tiny organisms in the surface layer of oceans) are threatened by increased UV radiation. Plankton are the first vital step in aquatic food chains.
    • Decreases in plankton could disrupt the fresh and saltwater food chains, and lead to a species shift in Canadian waters.
    • Loss of biodiversity in our oceans, rivers and lakes could reduce fish yields for commercial and sport fisheries.

  • Animals:
    • In domestic animals, UV overexposure may cause eye and skin cancers. Species of marine animals in their developmental stage (e.g. young fish, shrimp larvae and crab larvae) have been threatened in recent years by the increased UV radiation under the Antarctic ozone hole.

  • Materials:
    • Wood, plastic, rubber, fabrics and many construction materials are degraded by UV radiation.
    • The economic impact of replacing and/or protecting materials could be significant.


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