environmental issues class 12

2. What is pollution?
Pollution is any desirable change in physical, chemical or
biological characteristics of air, land, water or soil.
Pollutants:
agents that bring about such an undesirable change.

3. In order to control pollution government of
India has passed the ENVIRONMENT
(protection) ACT,1986 to protect and
improve the quality of our environment

4. AIR POLLUTION AND
ITS CONTROL:

5. Air pollution is an ‘undesirable change in
atmospheric air due to human intervention,
which makes air unfit for human use and for
the survival of flora and fauna’
The major sources of air pollution are
automobiles, industries, power plants,
smelters, agricultural operation, etc.
Also radioactive explosions, like the one in
Hiroshima and Nagasaki (cities of japan) in
1945 are the major causes for pollution.
Natural factors like volcanic eruptions(eg:
long lasting eruption of Kilauea) are the
major pollution factors which harm the
environment.

7. AIR POLLUTANTS:
a. Primary air pollutants
b. Secondary air pollutants
PRIMARY AIR POLLUTANTS:
Pollutants that are released by human activities and remain in the same form in which
they are released into the environment.
For example: carbon di oxide, ozone , carbon monoxide, etc.
SECONDARY AIR POLLUTANTS:
Pollutants formed when primary air pollutants undergo chemical reaction with
atmospheric gases.
For example: photochemical smog, acid rain, etc.

9. PREVENTIVE MEASURES:
 Minimize the burning of fossil fuels
 Concentrate on the usage of non polluting resources of energy
 Afforestation or plant trees
 Usage of better automobile engines with more energy efficient capacity
 Factories should be located away from residential areas.
 Govt. throughout the world should introduce green energy(energy that
has less negative impact on the environment than traditional energy
sources.)
 Encouraging to use public transport like buses
 Encourage to use energy wisely.

10. Control measures:
Electrostatic precipitator
Scrubber
Catalytic converter.

11. ELECTROSTATIC
PRECIPITATOR:
a device for removing
small particles, as of smoke,
dust, or oil, from a gas, as air, by
passing the gas first through an
electrically charged screen that
gives a charge to the particles,
then between two charged
plates where the particles are
attracted to one surface.

12. SCRUBBER:
are a diverse group of air pollution control devices that can be
used to remove some particulates and/or gases from industrial
exhaust streams.
CATALYTIC CONVERTER:
A catalytic converter is an exhaust emission control device that converts
toxic gases and pollutants in exhaust gases from an internal combustion
engine to less toxic pollutants by catalyzing a redox reaction.

13. Case study of delhi: Controlling vehicular pollution

14. New Delhi ties for first place, along with Beijing, China, for having the
world’s worst air. New Delhi is one of India’s most important cities
considering the fact that it is India’s capital. Unfortunately for it’s
inhabitants, New Delhi’s air is fatal. The statistics are alarming. Specific
to New Delhi, the numbers of vehicles on the road have increased by
sixty-five percent since 2003. The more vehicles on the road mean
that there are more harmful pollutants being put into the atmosphere.
Another main cause of Delhi’s air pollution is simply all the dirt that is
being left in the atmosphere creating a haze throughout the whole
city. Geography also plays a role in New Delhi’s traumatic air pollution
because it is a landlocked city unlike Mumbai or Chennai. There is no
coastal breeze eradicating the pollutants.

15.  Delhi has more cars than states of Gujarat and west Bengal put
together.
 It is ranked fourth among the 41 most polluted cities of the world.
 PIL: public interest litigation was filed in supreme courts of India as a
consequence govt. was asked to take appropriate measures within
specific time.
 These measures included switching over the entire fleet of public
transport that is buses from diesel to CNG. By the end of 2002 all the
buses of delhi ran on CNG.
 CNG is better than diesel because it burns more efficiently, very little
of it is left unburnt. CNG is cheaper, cannot be siphoned off by thieves
and adulterated.
 Main problem to switch over CNG is difficulty of laying down pipelines
for transport of CNG.
 Old vehicles in Delhi were phased out

17.  Use of unleaded petrol
 Use of low sulphur petrol and diesel
 Use of catalytic converters in vehicles.
 Application of stringent pollution level norms for
vehicles.
 Euro-2 norms stipulate that sulphur be controlled at
350 ppm in diesel and 150 ppm in petrol. Aromatic
compounds are to be contained at 42%.
 The goalmap is to reduce the sulphur to 50 ppm and
bring down the level to 35%.
 Mass emission standards ( bharat stage norms ) are no
more applicable to any city.
 Due to various efforts a substantial fall in carbon and
sulfur dioxides has been found in delhi between
1997 and 2005

19. Thank you