UV Index Program

UV and Ozone Layer

Most of the UV-B rays from the sun are screened out by the ozone layer, the veil of gas high in the atmosphere that acts as our planet's sunscreen. In the past few decades, the ozone layer has become thinner than it was before. This means more of the sun's UV-B rays can now reach the earth's surface. However, UV-B rays have always been with us - they are a natural part of the sun's rays. This means we should always be careful about spending too much time in the sun, even after the earth's ozone layer recovers.

• Fact sheet on the ozone layer
• Main Environment Canada site on the ozone layer
  
  You may also consult other documents on the ozone layer through the Topics button above.

The Green Lane^TM,
Environment Canada's World Wide Web Site.