Three oxygen atoms (O3)

Three oxygen atoms (O3)

Our planet's only natural sun screen, the ozone layer is located high in the earth's atmosphere. This layer of gas acts as an invisible filter which protects all life forms from over-exposure to the sun's harmful ultraviolet (UV) rays.

Ozone is a chemical cousin to the oxygen that we need to breathe: regular oxygen is at two-atom oxygen molecule (O₂), and ozone is made up three oxygen atoms (O₃). An important physical property of ozone is that it absorbs UV radiation very effectively, protecting the earth from most of these damaging rays.

The ozone molecules in the upper atmosphere are spread so thinly that if they were compressed to pure ozone at ground level, they would create a band only 3 mm thick, about the thickness of three dimes.

Ultraviolet radiation itself, plays a primary role in the formation of ozone. In the upper atmosphere, UV radiation causes oxygen molecules to break up, and create free oxygen atoms that attach themselves to intact oxygen molecules to form ozone. The total amount of ozone in the atmosphere is a balance between the rate at which it is produced by sunlight and the rate which it is destroyed in photochemical reactions with other gases. Once formed in the stratosphere, the concentration and distribution of ozone has a significant effect on the atmosphere's temperature and the movement of air currents around the world. Because photochemical reaction and transport processed vary with season and latitude, ozone concentrations are not uniform throughout the year or from one part of the globe to another. Generally, the ozone layer is thinner over the equator than over the poles.

At the beginning of the 1980s, scientist identified some disturbing and unnatural changes happening in the ozone layer.

posted by Nanang @ 10:04:00 PM