| The
ozone layer screens out the sun's harmful ultraviolet
radiation. Can we reverse its destruction? |
| |
| A
natural balance keeps us well supplied with ozone |
 |
Up
in the stratosphere, small amounts of ozone are
constantly being made by the action of sunlight
on oxygen. At the same time, natural processes are
breaking down ozone. |
|
| The total amount
of ozone usually stays constant because its formation
and destruction occur at about the same rate |
| Human activity has
recently changed that natural balance. Certain manufactured
substances (such as chlorofluorocarbons and hydro chlorofluorocarbons)
can destroy stratospheric ozone much faster than it is
formed. |
| |
| Ozone
is a natural sun block |
| The ozone layer
in the stratosphere blocks out the sun's deadly ultraviolet
rays. It acts as our planet's natural sun block |
| The sun doesn't
just produce heat and light. It throws out all sorts of
other types of electromagnetic radiation, including ultraviolet
radiation. Because ultraviolet radiation can damage DNA
it is potentially harmful too most living things, including
plants. Unfortunately our bodies can't detect ultraviolet
radiation directly. We can be unaware of the harm it is
doing until it is too late - for example, at the end of
a day in the sun without adequate protection. |
| |
| When
there is less ozone in the stratosphere, more ultraviolet
radiation hits us |
| Even a 1 per cent
reduction in the amount of ozone in the upper atmosphere
causes a measurable increase in the ultraviolet radiation
that reaches the Earth's surface. If there were no ozone
at all, the amount of ultraviolet radiation reaching us
would be catastrophically high. All living things would
suffer radiation burns, unless they were underground,
in protective suits, or in the sea, |
| |
| So
what exactly is ozone? |
| Ozone is a form
of oxygen. Each ozone molecule is made of three oxygen
atoms, so its chemical formula is O3. But unlike oxygen,
ozone is a poisonous gas, and an increase in its concentration
at ground level is not something that we want. But in
the stratosphere, where ozone exists naturally, it blocks
out the sun's ultraviolet rays and is a lifesaver. |
| More
on Ozone.... |
