Question

What are the main functions of the ozone layer in the Earth's atmosphere?

1. Absorption of harmful ultraviolet radiation
2. Generation of radio waves
3. Facilitation of long-distance communication
4. Regulation of atmospheric pressure

• A. i only
• B. i, iv
• C. iii only
• D. i, ii

Answer 1

Answer:

A. i only

The ozone layer 

• The ozone layer is a region of the Earth's stratosphere that contains a high concentration of ozone (O3) molecules.
• The ozone layer is mainly located in the Earth's stratosphere, primarily between 10 and 50 kilometers (6.2 and 31 miles) above the Earth's surface.

Function:

• Its primary role is to absorb the majority of the Sun's harmful ultraviolet (UV) radiation, particularly the biologically damaging UV-B and UV-C rays.
• This absorption prevents most of these potentially harmful rays from reaching the Earth's surface, protecting life forms from the adverse effects of excessive UV exposure, such as skin cancer, cataracts, and immune system suppression.

Formation: 

• Ozone is formed in the stratosphere through a series of photochemical reactions primarily involving ultraviolet light and oxygen molecules (O2).
• When high-energy ultraviolet rays strike oxygen molecules, they can split the oxygen molecules into two separate oxygen atoms. These individual oxygen atoms can then combine with other oxygen molecules to form ozone.

Depletion:

• The release of human-made chemicals, such as chlorofluorocarbons (CFCs), halons, and other ozone-depleting substances (ODS), has led to the depletion of the ozone layer.
• The resulting thinning of the ozone layer has led to the formation of the so-called "ozone holes" over certain regions, most notably over Antarctica and occasionally the Arctic.
• The depletion of the ozone layer has raised significant environmental concerns due to the potential increase in harmful UV radiation reaching the Earth's surface.
• In response to these concerns, the Montreal Protocol was enacted in 1987.
• This international treaty aimed to phase out the production of ozone-depleting substances, leading to a gradual reduction in their atmospheric concentration.