Science M.C.Q. [1 M]

The various greenhouse gases are carbon dioxide, methane, chlorofluorocarbons $(CFCs),$ and nitrogen oxide.
Other minor contributors are water vapours and ozone.
The rise in carbon dioxide concentration is due to large scale deforestation (for grazing land, cropping land or urban settlements), change in land use pattern and large scale combustion of fossil fuels.
Methane is produced by incomplete biomass combustion, incomplete decomposition mostly by anaerobic methanogens.
$CFCs$ are inert propellants used in aerosol cans and jet fuel, refrigerants in air conditioner and refrigerators.

Ozone layer or ozonosphere occurs in the stratosphere. It is generally lowest at the equator and highest in polar regions. It is present to a height of $23-25\ kms$ over the equator.

Man-made causes of depletion of ozone layer: The main cause for the depletionof ozone is determined as excessive release of chlorine and bromine from man-made compounds such as chlorofluorocarbons $(CFCs).$ The emission of $ODS$ account for roughly $90\%$ of total depletion of ozone layer in stratosphere.

Nitrogen gas makes up approximately. $78\%$ of our atmosphere and nitrogen is also a part of molecules essential for life like proteins, nucleic acids $(DNA$ and $RNA).$ It is thus an essential nutrients for all life forms.
The nitrogen molecules present in air can be converted into nitrates and nitrites by a biological process of nitrogen fixing bacteria (present in the soil or present in association with plants).

Suspended Particulate Matter $(SPM)$are finely divided matter particles that cause aur pollution. They may be dispersed into air by combustion or industrial processes. Dust, soot and smoke, flash are all Suspended Particulate Matter.

 Air is a mixture of gases. It contains $78 - 79\%$ nitrogen, $21\%$ oxygen, $0.93\%$ argon, $0.03\%$ carbon dioxide, and traces of hydrogen, helium, and other "noble" gases.

• Particulate matter $(PM10$ and $PM2.5)$
• Ozone $\left(\mathrm{O}_3\right)$
• Nitrogen dioxide $\left(\mathrm{NO}_2\right)$
• Carbon monoxide $(CO)$
• Sulphur dioxide $\left(\mathrm{SO}_2\right)$

Soil is the uppermost humus containing part of the Earth's surface, which can sustain terrestrial plant life.
Soil is composed of inorganic mineral particles $(45$ percent$),$ water $(25$ percent$),$ air $(25$ percent$),$ and
humus $(5$ percent$).$
Humus is composed up of dead and decaying organic material.

Due to the depletion of stratospheric ozone, a seasonal hole in the ozone layer at polar regions is formed in the atmosphere. This is known as the ozone hole.
The depletion of ozone causes harmful $UV$ rays to reach the earth. $UV$ radiations are responsible for causing skin cancers and various diseases in humans.