Ozone layer

What is Ozone Layer?

The ozone layer is a layer in Earth's atmosphere containing relatively high concentrations of ozone

The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson.

Why it is important for Earth?

Although the concentration of the ozone in the ozone layer is very small, it is vitally important to life because it absorbs biologically harmful ultraviolet (UV) radiation coming from the sun.

Regulation

In 1978, the United States, Canada and Norway enacted bans on CFC-containing aerosol sprays that are thought to damage the ozone layer. The European Community rejected an analogous proposal to do the same.

Activities

http://www.educaplay.com/es/recursoseducativos/675702/ozone_layer.htm

Components

Nitrogen

Oxygen

Argon

Carbon dioxide

Ozone

OZ

OZ

OZ

Ozone Layer in the atmosphere

The atmosphere

The atmosphere is a layer around the Earth that mantains its gravity. And it also protects life in Earth by absorbing many sunrays.

The ozone layer in the atmosphere

The ozone layer is inside the Atmosphere, in the stratosphere. Which is after the troposphere and before the Mesosphere, the Ionosphere (thermosphere) and de Exosphere.

Function

The ozone layer is a layer which protects the Earth from the UV (ultra violet) radiations which are originated in the sun. This UV radiations can cause skin cancer, suppressions to the immune system and eye cataract.

Today, the ozone layer is being destructed by the contamination produced in the Earth. As a consequence, many phenomena such as Global Warming or the Water Crisis are causing great damages on the Earth and in society.

Activity & videohttp://www.youtube.com/watch?v=WKrPd-8CJBM&feature=relatedhttp://www.educaplay.com/es/recursoseducativos/683252/ozone_layer.htm

Ozone Depletion

Ozone depletion describes two distinct but related phenomena observed since the late 1970s: a steady decline of about 4% per decade in the total volume of ozone in Earth's stratosphere (the ozone layer), and a much larger springtime decrease in stratospheric ozone over Earth's polar regions. The latter phenomenon is referred to as the ozone hole.

Chemicals in the atmosphere

Chlorofluorocarbons (CFCs) and other halogenated ozone depleting substances (ODS) are mainly responsible for man-made chemical ozone depletion. The total amount of effective halogens (chlorine and bromine) in the stratosphere can be calculated and are known as the equivalent effective stratospheric chlorine (EESC).

CFCs= Chemistry chlorofluorocarbon, any of a class of synthetic compounds of carbon, hydrogen, chlorine, and fluorine formerly used as refrigerants and aerosol propellants and known to be harmful to the ozone layer.

Ozone hole and it causes

As explained above, the primary cause of ozone depletion is the presence of chlorine-containing source gases (primarily CFCs and related halocarbons). In the presence of UV light, these gases dissociate, releasing chlorine atoms, which then go on to catalyze ozone destruction. The Cl-catalyzed ozone depletion can take place in the gas phase, but it is dramatically enhanced in the presence ofpolar stratospheric clouds (PSCs).

Consequences of ozone layer depletion

Since the ozone layer absorbs UVB ultraviolet light from the sun, ozone layer depletion is expected to increase surface UVB levels, which could lead to damage, including increase in skin cancer. This was the reason for the Montreal Protocol. Although decreases in stratospheric ozone are well-tied to CFCs and there are good theoretical reasons to believe that decreases in ozone will lead to increases in surface UVB, there is no direct observational evidence linking ozone depletion to higher incidence of skin cancer and eye damage in human beings.

Link of videos and an excersice:

http://www.youtube.com/watch?v=UfyOJb1widI

http://www.educaplay.com/es/recursoseducativos/675706/ozone_layer.htm

http://www.youtube.com/watch?v=qUfVMogIdr8