AIR POLLUTION
POLLUTION
·
Introduction of harmful materials into the
environment is called Pollution.
·
The agents responsible for causing Pollution
are called as Pollutants.
AIR POLLUTION
·
Air pollution occurs when harmful substances
including Particulate molecules, Gaseous molecules and Biological molecules are
introduced into Earth's atmosphere.
ü Particulate
molecules – Suspended particulate matter (SPM), Dust particles, Smoke,
Mist, Fumes, Spray, Benzopyrenes, Asbestos, Pesticides and Metallic dusts.
ü Gaseous
molecules – Inorganic gases (NO, NO2, SO2, CO, CO2,
O3, NH3, Cl & H2S) and Organic gases (Methane,
Acetylene, Ethylene, Ethyl radicals, Aldehydes & Alcohols)
ü Biological
molecules – Microorganisms, Spores and Pollens
·
Air pollution may cause diseases, allergies
or death in humans.
·
Human activity and natural processes can both
generate air pollution.
Types of Air Pollution
1) Indoor Air
Pollution
ü Pollutions
from the housing made materials and living and working activities of the house,
such as: Natural radiation - Radon, Domestic combustion - Coal gas, and Human habits
tobacco smoking.
2) Outdoor Air
Pollution
ü Pollutions
from outdoor services and environmental mixings, such as: Transportation - Automobiles,
Industries - Refineries, Atomic energy plant - Nuclear and Community activities
- Cleaning of streets.
Air Pollutants
·
A substance in the air that can be averse to
humans and the environment is known as an Air pollutant.
·
Pollutants can be in the form of Solid
particles, Liquid droplets or Gases. In addition, they may be Natural or
Man-made.
Types of Air Pollutants
·
Pollutants can be classified as Primary or
Secondary.
1) Primary
pollutants are the pollutants that are pumped into our atmosphere and
directly pollute the air.
ü Example –
Sulphur oxides, Nitrogen oxides, Carbon monoxide, Volatile organic compounds,
Toxic metals (Lead and Mercury), Chloroflurocarbon (CFC), Ammonia and
Radioactive pollutants.
2) Secondary
pollutants are those harmful substances that are created from the reactions
between primary pollutants and the components of the atmosphere.
ü Example
a) Ozone,
formed when Hydrocarbons (HC) and Nitrogen oxides (NOx) combine in the presence
of sunlight.
b) NO2, formed as NO combines with Oxygen
in the air.
c) Acid rain formed when Sulfur dioxide or Nitrogen
oxides react with water.
Factors responsible for Air Pollution
1) Natural
sources
ü Dust from
natural sources, usually large areas of land with few or no vegetation.
ü Methane,
emitted by the digestion of food by animals, for example cattle.
ü Radon gas
from radioactive decay within the Earth's crust. Radon is a colorless,
odorless, naturally occurring, radioactive noble gas that is formed from the
decay of Radium.
ü Smoke and Carbon
monoxide from wildfires.
ü Volcanic activity,
which produce sulfur, chlorine, and ash particulates.
2) Man – made
sources
ü "Stationary
Sources" include smoke stacks of power plants, manufacturing facilities
(factories) and waste incinerators, as well as furnaces and other types of
fuel-burning heating devices.
ü "Mobile
Sources" include motor vehicles, marine vessels, aircrafts, etc.
ü Chemicals,
dust and controlled burn practices in agriculture and forestry management.
ü Fumes from
paint, hair spray, varnish, aerosol sprays and other solvents.
ü Waste
deposition in Landfills, which generate Methane. Methane is highly flammable
and may form explosive mixtures with air.
ü Military,
such as nuclear weapons, toxic gases, germ warfare and rocketry.
Effects of Air Pollution
1) Respiratory
and Heart failure
o
The effects of Air pollution are known to
create several respiratory and heart conditions along with Cancer, among other
threats to the body.
o
Several millions are known to have died due
to direct or indirect effects of Air pollution.
o
Children in areas exposed to air pollutants
are said to commonly suffer from Pneumonia and Asthma.
2) Global
warming
o
Another direct effect is the immediate
alterations that the world is witnessing due to Global warming.
o
With increased temperatures worldwide, increase
in sea levels and melting of ice from colder regions and icebergs, displacement
and loss of habitat have already signaled an impending disaster if actions for
preservation and normalization aren’t undertaken soon.
3) Acid rain
o
Harmful gases like Nitrogen oxides and Sulfur
oxides are released into the atmosphere during the burning of fossil fuels.
o
When it rains, the water droplets combines
with these air pollutants, becomes acidic and then falls on the ground in the
form of Acid rain.
o
Acid rain can cause great damage to human,
animals and crops.
4) Eutrophication
o
Eutrophication is a condition where high
amount of nitrogen present in some pollutants gets developed on sea’s surface and
turns itself into algae and adversely affect fish, plants and animal species.
o
The green colored algae that is present on
lakes and ponds is due to presence of this chemical only.
5) Effect on
Wild life
o
Toxic chemicals present in the air can force
wildlife species to move to new place and change their habitat.
o
The toxic pollutants deposit over the surface
of the water and can also affect sea animals.
6) Depletion of
Ozone layer
o
Ozone exists in earth’s stratosphere and is
responsible for protecting humans from harmful Ultraviolet (UV) rays.
o
Earth’s ozone layer is depleting due to the
presence of chlorofluorocarbons, hydro chlorofluorocarbons in the atmosphere.
o
As ozone layer will go thin, it will emit
harmful rays back on earth and can cause skin and eye related problems.
o
UV rays also have the capability to affect
crops.
Solutions for Controlling Air pollution
1) Use public
mode of transportation
o
Encourage people to use more and more public
modes of transportation to reduce pollution.
2) Conserve
energy
o
Switch off fans and lights when you are going
out.
o
Large amount of fossil fuels are burnt to
produce electricity. You can save the environment from degradation by reducing
the amount of fossil fuels to be burned.
3) Understand
the concept of Reduce, Reuse and Recycle
o
Do not throw away items that are of no use to
you.
4) Emphasis on
clean energy resources
o
Clean energy technologies like solar, wind
and geothermal are on high these days.
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