Today, large population pressure is exerting tremendous pressure on our natural resources. Pollution has led to an increase in the average temperature of our planet and threatens existence of life on earth.

1. Seminar on “Environmental
Issues, Air Pollution and
Controls”
PREPARED BY:-
RAHUL DUBEY
3rd SEM MECHANICAL
ENGG.
SUBMITTED TO:-
Ms. CHETNA WAHANE
Mr. PRABHAT SINGH
RATHORE

2. CONTENTS
• INTRODUCTION
• WHAT IS ENVIRONMENT?
• WHAT IS POLLUTION?
• BASIC CAUSES OF POLLUTION
• ENVIRONMENTAL MONITORING
• TYPES OF POLLUTION
• AIR POLLUTION
• CAUSES OF AIR POLLUTION
• AIR POLLUTANTS
• AIR POLLUTION CONTROLS
• ENVIRONMENTAL ISSUES
• CONCLUSION

3. INTRODUCTION
• Large human population is exerting
tremendous pressure on our natural
resources.
• With increase in human population and
great advancement in technology in the
recent past, the waste materials have
multiplied in amount as well as in kind,
and this has resulted in contamination
of environment.

4. • Today, almost every aspect of modern
living possess potential health risks.
• Natural Resources like air, water, land,
etc. are getting contaminated with
toxic substances or chemical additives.
• It is possible that ultimately man may
become a victim of self-created
pollution.
• These global environmental changes
are influencing not only air, water and
land resources but also biological
diversity and human health.

5. WHAT IS ENVIRONMENT?
• Environment is the physical, chemical,
biological, cultural and aesthetic surrounding
of living organisms, which contributes to the
quality of their lives.
• Our environment is a complex and dynamic
system, in which all forms of life are inter-
dependent and inter-connected.

6. WHAT IS POLLUTION?
• Pollution is any undesirable
change in physical, chemical or
biological characteristics of
environment which makes it
harmful for humans, living
organisms and cultural assets.
• Agents that bring about such an
undesirable change are called as
pollutants.

8. ENVIRONMENTAL MONITORING: PROCEDURE
FOR THE CONTROL OF POLLUTION
The control of pollution requires environmental
monitoring. This, in turn, needs
• Careful study of environmental characteristics,
• Laying down environmental quality standards,
• Periodic assessment of environmental
characteristics,
• Noting the changes in the environment and
finding out their likely effect,

9. • Warning people in time of likelihood of
pollution, and
• Planning strategies to tackle pollution such as
educating people about pollution hazards,
enacting environmental laws, legal action
against offenders, etc.

10. PLAN
SAMPLING
ASSIGN
WORK
COLLECT
SAMPLES
PROCESS
SAMPLES
REVIEW
RESULTS
ANALYSE
RESULTS

11. DUST COLLECTOR

12. POLLUTION IS OF FOLLOWING
MAIN TYPES:-
1. Atmospheric or air pollution,
2. Hydrospheric or water
pollution,
3. Lithospheric or land or soil
pollution,
4. Radioactive pollution, and
5. Noise or sound pollution.

14. AIR POLLUTION
• An undesirable change in the
physical, chemical, or biological
aspects of air which makes it
harmful for humans, for other
living organisms and for cultural
assets is called air pollution.

16. a. HUMAN ACTIVITIES
• Industrialisation
• Automobile emissions
• Overpopulation
• Deforestation
• Nuclear explosion and explosives used in
wars
• Fireworks
• Thermal power stations, etc.

17. b. NATURAL PHENOMENA
• Volcanic eruptions
• Electric storms and solar flares which
produce harmful chemicals
• Forest fires
• Natural organic and inorganic decays
• Dust storms
• Biological elements like pollen, spores, cysts,
bacteria and marsh gas.

18. • GASEOUS AIR POLLUTANTS
• PARTICULATE POLLUTANTS
• RADIOACTIVE POLLUTANTS

19. GASEOUS POLLUTANTS
• Oxides of sulphur
• Hydrogen sulphide
• Oxides of nitrogen
• Oxides of carbon
• Hydrocarbons
• Photochemical oxidants
• Fluorides

20. PARTICULATE POLLUTANTS
• Dusts
• Mists
• Aerosols
• Pollen, spores, cysts and
bacteria, etc.

21. RADIOACTIVE POLLUTANTS
• They are released from
nuclear and war explosives.
• They kill the tissues they
enter.

22. LUNG DAMAGE DUE TO
PARTICULATES

23. Three types of steps
can be taken to
control air pollution:-
• Separation of pollutants
from harmless gases,
• Avoidance of pollutants
• Conversion of pollutants
to harmless materials.

24. SEPARATION OF POLLUTANTS
 Growing trees: certain plants (Phaseolus
vulgaris, Coleus blumeri, Ficus variegata) can
fix CO and some plants (Pinus, Junipers,
Quercus, Pyrus, Vitis) can metabolise
nitrogen oxides. Plantation of such species
should be encouraged along with other
plants
 Use of sulphur and lead free good quality
fuel.

25.  Control of Particulate Matter:- we can use
devices termed arrestors in the industries and
catalytic converters in the automobiles.
• Arresters :- Control equipments such as gravity
settling tanks or porous filters, electrostatic
precipitators, cyclonic separators and
trajectory separators can minimise air
pollution.
• Catalytic converters:- This device has metals
like platinum, palladium and rhodium as
catalysts. As the exhaust passes through it,

28. unburnt hydrocarbons are converted into CO₂
and water, and CO and nitric oxide are changed
to CO₂ and N₂ respectively.
 Control of Gaseous Pollutants:-
1. Combustion method:- In this method,
oxidisable pollutants particularly in
petrochemical, fertilisers, paints and varnish
industries are burnt at high temperature.
2. Absorption method:- This method employs
dry or wet scrubbers having packing material
where gaseous pollutants are absorbed.

29. For instance, calcium hydroxide or a bed of lime
is used to absorb sulphur dioxide. A fine spray of
water dissolves nitrogen oxides, sulphur oxides
and ammonia.
3. Adsorption technique:- This method is
employed to remove toxic gases, vapour and
inflammable compounds from the polluted air
by using very fine solid particles (e.g., activated
charcoal). The electrostatic precipitators
remove smaller particles.
Using tall chimneys in factories reduce pollution
of air at ground level.

30. Industrial smoke should be filtered before
releasing into the air to remove particulate
matter.
Poisonous gases should be removed by
passing the fumes through water tower
scrubber or spray collector.
Mining area should be afforested.

31. AVOIDANCE OF POLLUTANTS
• Use of automobiles should be minimised.
• Conventional fuels (firewood, coal, oil)
should be replaced by electricity or natural
gas. These fuels do not emit SO₃.
• Population should be brought under control.
• Nuclear explosions and wars should be
stopped.
• Non-conventional fuel should be used which
are pollution free.

32. • Pollution free fuels (alcohol, hydrogen,
battery power) should be developed for
automobiles.
• Complete electrification of rail track will
greatly reduce air pollutants.

33. CONVERSION OF
POLLUTANTS
• It means conversion of
pollutants into harmless
materials.
• This may be done by oxidation in
air or by chemical neutralisation
of acids and bases.

35. Acid Rain
• Acidification of environment is a man-made
phenomenon.
• Acid rain refers to precipitation with a pH of
less than 5.
• It is a mixture of H₂SO₄ and HNO₃; the ratio of
the two acids vary depending on the relative
quantities of sulphur oxides and nitrogen
oxides present in the atmosphere.

36. • In the atmosphere, SO₂ and Noₓare
changed into sulphuric acid (H₂SO₄) and
nitric acid (HNO₃) respectively by
combining with oxygen and water.
2SO₂ + O₂ → 2SO₃
SO₃ + H₂O → H₂SO₄
2NO + [O]→ N₂O₅
N₂O₅ + H₂O → 2HNO₃

38. EFFECTS OF ACID RAIN
• Chlorosis
• Necrosis
• Defoliation
PLANTS
• Results in acidification of water bodies
• pH less than 5 kills plankton, molluscs and most
fishes in water bodiesFAUNA
• Corrodes metals, marbles, painted
surfaces, slate, stone, etc.
• Causes stone leprosy.
ASSETS

39. Green House Effect and Global
Warming
• The greenhouse effect is a naturally occurring
phenomenon that is responsible for heating of
earth’s surface and atmosphere.
• Only half of incoming solar radiations fall on
Earth’s surface heating it.
• Earth’s surface re-emits heat in the form of
infra-red radiation but part of it doesn’t
escape into space as atmospheric gases (e.g.,
CO₂, CH₄, etc.) absorb a major fraction of it.

40. • The molecules of these gases radiate heat
energy, and a major part of which again comes
to earth’s surface, thus heating it up once again.
The cycle repeats many times.
• The above mentioned gases are called
greenhouse gases because they are responsible
for the greenhouse effect.
• Increase in the level of greenhouse gases has led
to considerable heating of earth leading to
global warming.

41. Melting of polar and Himalayan
ice caps.
Global environmental changes
(e.g., El Nino Effect) and rise in
the earth’s average temperature
The total spectrum of changes
that global warming can bring is
still under active research

42. ENERGY
PLANTATION
MISCELLANEOUS
• Cutting down use of
fossil fuels
• Increasing energy
efficiency
• REDUCING
DEFORESTATION
• PLANTING TREES
• Slowing down the
population growth rate
• International initiatives like
setting up norms for the
countries of the world, etc.

45. Ozone Depletion
• Ozone layer in the upper part of the atmosphere
acts as a shield absorbing UV radiation from the
sun.
• Ozone is continuously formed by the action of UV
rays on molecular oxygen, and also get degraded
into molecular oxygen in the stratosphere.
• This balance between production and
degradation of ozone in the stratosphere has
been disrupted due to enhancement of ozone
degradation by chlorofluorocarbons (CFCs).

46. • In stratosphere, UV rays act on CFCs releasing Cl
atoms.
• Cl degrades ozone releasing molecular oxygen, with
these atoms acting merely as catalysts; Cl atoms are
not consumed in the reaction. Thus, a single Cl
atom can degrade large amount of ozone.
• Although ozone depletion is occurring widely in the
stratosphere, the depletion is particularly marked
over the Antarctic region.
• This has resulted in formation of a large area of
thinned ozone layer, commonly called as the ozone
hole.

47. OZONE DEPLETION

49. MONTREAL
PROTOCOL
• Agreement signed by 27 countries to limit the use of Ozone Depleting
Substances.
• Agreement to help developing countries implement the alternatives to CFCs.
EARTH
SUMMIT
• United Nations Conference on Environment and Development (commonly
called EARTH SUMMIT)was held in Rio de Janero in 1992.
• Recommendations of Conference on Climate Change were signed by 154
nations to limit the emissions of greenhouse gases at 1990 level.
KYOTO
PROTOCOL
• An agreement was signed by different countries in 1997 to mitigate global
environmental change by taking appropriate measure to reduce emissions of
greenhouse gases at a level 5% below the 1990 level by 2012.

50. CONCLUSION
• Today, our environment is facing anthropological
threats.
• Burning issues of global environmental change like
global warming and ozone depletion are
threatening the existence of living world.
• The need of the hour is to stabilise the
atmospheric concentrations of green house gases
which is possible only when all the countries join
hands in lowering the global emission of green
house gases from their present levels.