1. Newsletter
the ozone
Ozone layer The future
Ultraviolet
What you can do
light &ozone
Fixing the
Ozone depletion
problem
Teamwork
2. Ozone layer
The ozone layer is a layer of Earth’s atmosphere which contains
high concentrations of ozone (O3). This layer absorbs
the sun's ultraviolet light, which damages life on Earth.
It is mainly located in the lower portion of the stratosphere from 20
to 30 kilometers above Earth.
The ozone layer was discovered in 1913 by the French physicists
Charles Fairy and Henri Buisson. Its properties were explored in
detail by the British meteorologist G.M.B Dobson, who developed
a simple spectrophotometer that could be used to measure
stratospheric ozone from the ground. Between 1928 and 1958
stations, Dobson established a worldwide network of ozone
monitoring which continue to operate to this day.
3. Ultraviolet light and ozone
The ozone is important to life because it absorbs harmful ultraviolet
.(UV) radiation coming from the sun
:UV radiation is divided into three categories based on its wavelength
UV-A (400–315 nm), UV-B (315–280 nm), and UV-C (280–100 nm).
.UV-C , which would be very harmful to all living things
UV-B radiation can be harmful to the skin and is the main cause of
sunburn , it also causes genetic damage, resulting in problems such as
.skin cancer
The ozone layer is very effective at examine UV-B; for radiation with a
wavelength of 290 nm. the intensity at the top of the atmosphere is 350
,million times stronger than at the Earth`s surface. Nevertheless
.some UV-B reaches the surface
4. Ozone depletion
The ozone layer can be depleted by CFCs, nitric oxide (NO), nitrous
oxide (N2O), hydroxyl (OH), atomic chlorine (Cl), and atomic bromine
(Br). While there are natural sources for all of these species. the
concentrations of chlorine and bromine have increased markedly in
recent years due to the release of large quantities of man-made organ
halogen compounds, especially chlorofluorocarbons (CFCs) and
.bromofluorocarbons
These compounds rise to the stratosphere, where the radiation breaks
down them into molecules
,These molecules become unable to absorb ultraviolet radiation. Thus
.dangerous ultraviolet-B radiation reach the Earth’s surface
In the 1970s,Scientists have noticed that the ozone over
Antarctica became thinner each spring. By 1992, this area was
more than twice as large as the continental United States.
5. Fixing the problem
In 1979, many countries, including the U.S., banned CFCs
from being made or used. This was a big step toward fixing
the problem. Today, no spray cans contain CFCs. Other
chemicals are gradually replacing the CFCs in air
.conditioners
But the CFCs already in the atmosphere can take up to 50
years to reach the stratosphere. Once there, they hang
.around in the stratosphere for many years, doing damage
Also, the products that still contain CFCs need to be treated
with care. One example of this is a car air conditioner. When
the air conditioner breaks, or the car is taken to a junkyard,
the CFCs need to be carefully taken out and recycled or
.stored so that they don't leak into the air
6. The future
Scientists originally predicted that the
ozone layer would be the thinnest
around 2008, then start recovering. But
new research shows that other air
pollution problems are slowing down
.the ozone layer's ability to rebound
7. What you can do
Encourage people with cars to have their air
conditioners fixed by mechanics who are
certified to handle. In Wisconsin, by law,
mechanics have to be specially certified to
.work with CFCs
Protect your skin and eyes from
.harmful UV rays when you're outside
8. Teamwork
Editor: Afaf Alkhalil
Designer :Batool Abdeen
Publisher :Alia Dweko& Marwa Attar
Alkods High School
Grade: second secondary scientific
Supervisor:Mrs. Tonia Bitar
toniabitar@gmail.com
Resources
http://www.izotope.com/products/audio/ozone/
http://www.ozone.org/