The ozone layer forms a thin shield high up in the sky. It protects life on Earth from the sun's ultraviolet (UV) rays. In the 1980s, scientists began finding clues that the ozone layer was going away or being depleted. This allows more UV radiation to reach the Earth's surface. This can cause people to have a greater chance of getting too much UV radiation. Too much UV can cause bad health effects like skin cancer, eye damage, and get you sick easier.

Ozone is a natural gas that is found in two different layers of the atmosphere. In the layer around the Earth's surface (the troposphere) ground-level, or bad ozone dirties the air and helps make smog. The troposphere extends up to the stratosphere layer, where good ozone protects life on Earth by absorbing some of the sun's UV rays. Stratospheric ozone is found most often between six to 30 miles above the Earth's surface.

Ozone Depletion

Recently, chlorofluorocarbons (CFCs) were used a lot in industry and elsewhere to keep things cold, make foam, and soaps. Strong winds carry CFCs into the stratosphere. This can take two to five years. When CFCs break down in the stratosphere, they release chlorine. Each chlorine atom attacks ozone by joining with and breaking apart as many as 100,000 ozone molecules during the time it is in the stratosphere.

Other ozone eating chemicals are pesticides such as methyl bromide, halons used in fire extinguishers, and methyl chloroform used in businesses.

What Is Being Done?

Countries around the world, including the United States, have seen the threats created by ozone depletion and agreed to a treaty called the Montreal Protocol. This Protocol will help humans to stop making and using ozone-eating chemicals.

How Ozone Depletion Affects UV Levels

Scientists predict that ozone depletion should peak between 2000 and 2010. As world wide controls reduce the release of CFCs and other ozone-eating substances, nature will repair the ozone layer to 1979-1980 levels around 2065. Until then, we can expect higher levels of UV radiation at the Earth's surface. Higher UV levels can lead to a greater risk of too much UV radiation and bad health effects.