| HOME| ABOUT| NEWS| PUBLICATIONS| CONTACT|
 
Air page banner
Air
 
 
My Environment
MY ENVIRONMENT
 
Business Resources
RESOURCES FOR BUSINESSES
 
Air
AIR
 
Land
LAND
 
Water
WATER
 
E-Zone
E-ZONE
 
Obviously.ca
OBVIOUSLY.CA

General Information on ODS

Regular font size Large font size Extra large font size Print this page
Aerial shot of the planet earth.

Are ozone depleting substances bad for me?

The ozone shield screens the earth from some of the sun's harmful ultraviolet rays - UVB. As that layer is depleted, higher UVB levels are present. 

Increased exposure to UVB causes nonmelanoma skin cancer and plays a major role in malignant melanoma development. Overexposure to UV radiation may also suppress proper functioning of the body's immune system and the skin's natural defences. UV radiation can also increases the likelihood of cataracts, a form of eye damage in which a loss of transparency in the lens of the eye clouds vision. If left untreated, cataracts can lead to blindness.

Ozone depletion and climate change are both mainly caused by changes in the atmosphere due to human activities. Global warming is due to the build-up of heat-trapping gases in the atmosphere and is not caused by ozone depletion. Some chemicals which deplete ozone, such as CFCs, also trap heat in the atmosphere and contribute to global warming.

Return to top

What are ozone depleting substances?

Certain chemicals are recognized as ozone-depleting substances (ODS) because they breakdown in the stratosphere and release chlorine or bromine, which destroy the stratospheric ozone layer. Most ODS are also greenhouse gases.

Return to top

What are chlorofluorocarbons?

Chlorofluorocarbons (CFCs) are the most well known ozone depleting substances, and were the most used.  CFCs are a family of long-lasting synthetic chemicals that were developed about 60 years ago as a substitute for ammonia in refrigerators and air conditioners. They have also been used as blowing agents in foam product manufacturing, as cleaning solvents for electrical components, in aerosol sprays, and in hospital sterilization procedures.

Return to top

Where do ozone depleting substances come from?

The most common uses of ozone depleting substances are as refrigerants in commercial, home and vehicle air conditioners and refrigerators, foam blowing agents, solvents, aerosol spray propellants, fire extinguishing agents and chemical reactants.

Return to top

How does ozone depletion happen?


The ozone depletion process begins when chlorofluorocarbons (CFCs) and other ozone-depleting substances (ODS) leak from equipment (1). Winds efficiently mix the troposphere and evenly distribute the gases. CFCs are extremely stable, and do not dissolve in rain. After a period of several years, ODS molecules reach the stratosphere, about 10 kilometres above the Earth's surface (2).

Strong ultra-violet (UV) light breaks apart the ODS molecule. CFCs release chlorine atoms, and halons release bromine atoms (3). It is these atoms that actually destroy ozone. It is estimated that one chlorine atom can destroy over 100,000 ozone atoms before finally being removed from the stratosphere (4).

Large increases in stratospheric chlorine and bromine remove ozone faster than natural ozone creation reactions can keep up. Therefore, ozone levels fall.

Since ozone filters out harmful UVB radiation, less ozone means higher UVB levels at the surface. The more depletion, the larger the increase in incoming UVB (5). UVB has been linked to skin cancer, cataracts, damage to materials like plastics, and harm to certain crops and marine organisms. Although some UVB reaches the surface even without ozone depletion, its harmful effects will increase as a result of this problem (6).

Return to top

Information and Resources

Return to top