introduction to air pollution and top 5 air pollution disasters that swept away thousands of people.

2. INTRODUCTION
Ms. G. Tejasri
Assistant professor
Department of Civil Engineering
Gudlavalleru Engineering College – 521356.

3. World’s Top 5 Air Pollution disasters
1. Bhopal gas tragedy (India)
2. Chernobyl disaster (Russia)
3. Seveso disaster (Italy)
4. London smog (England, UK)
5. Grand canyon of Colorado (USA)

4. Bhopal gas tragedy
• Duration :2nd and 3rd of December, 1984.
• Reason: Methyl Iso cyanate (MIC).
• The Union Carbide pesticide plant in Bhopal India leaked
MIC. This tragedy was a result of water entering a tank
containing around 42 tons of MIC, creating a chemical
reaction that raised temperatures to over 200°c, increasing the
pressure making the tank vent the toxic gas which caught in
the Northwesterly wind passing over Bhopal.
• To this day, groundwater and soil in areas even 3km away
from the factory contains almost 40 times more pesticides than
Indian standards. The soil and water also contain toxic metals
like lead, mercury, arsenic, cadmium and chromium.

5. Chernobyl disaster (Russia)
• On 26 April 1986, reactor four suffered a catastrophic
power increase, leading to explosions in its core. This
dispersed large quantities of radioactive fuel and core
materials into the atmosphere and ignited the combustible
graphite moderator. The burning graphite moderator
increased the emission of radioactive particles, carried by
the smoke, as the reactor had not been encased by any kind
of hard containment vessel. The accident occurred during an
experiment scheduled to test a potential safety emergency
core cooling feature, which took place during a normal
shutdown procedure.
• The battle to contain the contamination and avert a greater
catastrophe ultimately involved over 5,00,000 workers and
cost an estimated 18 billion rubles.

6. The burnt nuclear plant

7. London smog
• Duration : December 5 to December 9, 1952
• Death toll : approximately 12,000 people
• Reason: When a thick fog engulfed London it mixed
with black smoke emitted from homes and factories
to create a deadly smog.

9. Seveso disaster
• On midday of July 10, 1976 an explosion occurred in a TCP
(2,4,5-trichlorophenol) reactor in a chemical company in
Meda, Italy. A toxic cloud escaped into the atmosphere
containing high concentrations of TCDD (tetra chloro di-
benzo dioxin), a highly toxic form of dioxin. Downwind
from the factory the dioxin cloud polluted a densely
populated area of 6 km long and 1 km wide, immediately
killing many animals. A neighboring municipality that was
highly affected is called Seveso. The accident was named
after this village. The dioxin cloud affected a total of 11
communities.
• The most remarkable feature of the Seveso accident was
that local and regional authorities had no idea the plant was
a source of risk.

10. Grand canyon of Colorado

11. • Regional haze is the "dirty-looking" air that
prevents us from seeing clearly or very far
through the air. It especially affects our
enjoyment of national parks, such as the Grand
Canyon.
• Sulfate particles, formed by the reaction of
sulfur dioxide (SO2) from power plants and
other sources in the atmosphere, account for 50
to 70 percent of the visibility reduction.

12. Effects on Human
Chloracne

13. Damage to vegetation
Necrosis: Acid rain damage to plants

14. The red forest

15. Effects on animals
Piglet affected due to radiations A unique kitten with single eye

16. Damage to art treasures

17. Damage to Art treasures
Great art treasures suffering from stone leprosy or stone cancer

18. Accidents due to visibility problem

19. Visibility problem spoiling the
natural scenic beauty

20. Conclusion
• These situations are like alarms for
other countries to avoid similar kind
of mishaps.

22. Air pollution (AP)
• As per IS :4167-1966, the presence in ambient
atmospheres of substances, generally resulting
from the activity of man, in sufficient
concentration , present for a sufficient time and
under circumstances such as to interfere with
comfort, health or welfare of persons or with
reasonable use or enjoyment of property is
called “AIR POLLUTION”

23. Threshold Limiting Value (TLV)
• The maximum concentration to
which healthy adult workers may be
exposed 8 hours a day for 5
continuous days a week without
adverse effects.
• E.g. : o.2 ppb and 5 ppm are the for
desirable and threshold limits of SOx
respectively.

24. Classification of Air
Pollutants
Based on
chemical
composition
Based on origin
Based on state
of matter

25. Classification based on chemical
composition
Organic
• Compounds of carbon and
hydrogen.
• e.g. aldehydes, ketones,
ether, alcohols etc.
Inorganic
• Found in polluted
atmosphere
• e.g. NOx, SOx, CO, HF,
HCl, CO2 etc.

26. Classification based on origin
Primary pollutants
• Primary pollutants are
substances that are directly
emitted into the atmosphere
from sources.
• E.g.: Carbon compounds,
such as CO, CO2, CH4, and
VOCs. Nitrogen
compounds, such as NO,
N2O, and NH3. Sulfur
compounds, such as H2S
and SO2.
Secondary pollutants
• Secondary pollutants are not
directly emitted from sources,
but instead form in the
atmosphere from primary
pollutants (also called
“Precursors”).
• E.g.: NO2 and HNO3 formed
from NO, Ozone (O3) formed
from photochemical reactions
of nitrogen oxides and VOCs,
Smog, Sulfuric acid droplets
formed from SO2 and nitric
acid droplets formed from
NO2.

27. Formation of Secondary pollutants

28. Classification based on state of
matter
Particulate
• Finely divided solids and
liquids
• Under normal conditions, they
settle out of atmosphere.
• May contain materials with
toxic or carcinogenic effects.
• Extremely small particles can
become lodged in lungs
• E.g. : smoke, fog, fume, mist,
aerosol, dust
Gaseous
• They are form less fluids
that completely occupy the
space into which they are
released and behave like air.
• They don't settle out of
atmosphere.
• E.g. : Hydrocarbons, NH3,
HF, CO, SOx and NOx

29. Sources of AP
Natural/ geogenic
1. Of natural occurrence
2. Contribute to the
composition of earth’s
atmosphere.
3. Causes more pollution
4. Uncontrollable
5. Equally distributed all over
the world
• e.g. volcanic eruptions, sea
salt sprays, SPM, RPM, radio
active materials, atmospheric
reactions.
Artificial/ Anthropogenic/ Man
made
1. Occurs due to manmade
activities
2. Causes less pollution
3. Controllable
4. Gets distributed based on
type and size of the
industry, development.
• e.g. pollution from industrial
stacks, aircrafts, fumes from
vehicles(CO, SOx and NOx )

30. Formation of Photochemical Smog

31. Formation of acid rains

32. Effects on human beings
S.No.: Pollutant Health effects
1. HCHO -Odors cause irritation to eye, skin, respiratory
system
-Effects Central Nervous System (CNS)
-Causes Cardiovascular problems
2. NH3 -Corrosive to mucous membrane
-Causes damage to eye and respiratory tract
3. SO2 -Air starvation when mixed with body fluids , forms
sulfuric acid which is a strong and corrosive acid.
4. CO -When inhaled, combines with blood and forms carb-
oxy hemoglobin
-Asphyxiation
-Very poisonous
-Persons look pale in color

33. Effects on human beings
S.No.: Pollutant Health effects
5. NOx -When inspired, even minute concentration causes
chronic irritation of respiratory tract, head ache
-Loss of appetite
-Causes corrosion of teeth
6. O3 -At high concentration, smells like chlorine
-Poisonous even at low concentrations
-Leads to asthma attacks
7. H2S -Causes headache, sleeplessness, eye pain,
conjunctivitis
-In high concentration, can lead to blockage of
oxygen transfer, acts as cell poison and damage nerve
tissues.
8. PM -Repiratory track problems
-Clinges to skin, hair and get adsorbed into body
-Causes silicosis, lung cancer diseases.

34. Assignment
• Rank of Bhopal gas tragedy amongst world’s
disasters.
3
• Hiroshima and Nagasaki Atomic bomb disaster
– a case study.
• Most polluted city in India is ?
Delhi