ENVIRONMENTAL POLLUTION
Pollution is the introduction of pollutants (chemical substances, noise, heat, light, energy and others)
into the environment which results in deleterious effects of such a nature as to endanger human
health, harm living resources and ecosystems, and impair or interfere with amenities and other
legitimate uses of the environment.
Major forms of pollution
The major forms of pollution are listed below along with the particular pollutants relevant to each of
them:
1. Air pollution, the release of chemicals and particulates into the atmosphere. Common
examples include carbon monoxide, sulfur dioxide, chlorofluorocarbons (CFCs), and
nitrogen oxides produced by industry and motor vehicles. Photochemical ozone and smog are
created as nitrogen oxides and hydrocarbons react to sunlight.
2. Water pollution via surface runoff, leaching to groundwater, liquid spills, wastewater
discharges, Eutrophication and littering.
3. Soil contamination occurs when chemicals are released by spill or underground storage tank
leakage. Among the most significant soil contaminants are hydrocarbons, heavy metals,
herbicides, pesticides and chlorinated hydrocarbons.
4. Radioactive contamination, added in the wake of 20th-century discoveries in atomic physics.
5. Noise pollution, which encompasses roadway noise, aircraft noise, industrial noise as well as
high-intensity sonar.
6. Light pollution, includes light trespass, over-illumination and astronomical interference.
7. Visual pollution, which can refer to the presence of overhead power lines, motorway
billboards, scarred landforms (as from strip mining), open storage of trash or municipal solid
waste.
8. Thermal Pollution is a temperature change in natural water bodies caused by human
influence.
AIR POLLUTION
Definition: the presence in the air of substances generally originating from manmade/natural
activities in concentrations that interfere with the health, comfort, and safety of living beings. It can
be indoor as well outdoor Air pollution. However, our discussion will be restricted to Outdoors type.
CLASSIFICATION OF AIR POLLUTANTS
1. Origin of pollutants
, a. Primary pollutants: emitted directly from source, say, release of SO2 from burning of
coal.
b. Secondary Pollutants: Formed due to interaction of two or more primary and secondary
pollutants, say for instance Acid rain, Ozone, PAN, Smog etc.
2. States of Matter
a. Particulates: composed of solid-liquid --- inert/reactive particles sized 2x10-4 – 500
microns. e.g., dust/smoke
b. Gaseous: SO2, CO, H2S, CH4, CO2 and O3
3. Chemical composition
a. Organic: Aldehydes, Esters, ethers, and amines Inorganic: NOx, SO2, NH3, H2S and O3
b. Physical: Dust, fly ash, spray, pollen, smoke, mist and fumes Chemical:
c. Organic – Inorganic
d. Biological: Protozoa, Bacteria, Fungi and Virus.
Chernobyl Nuclear disaster
April, 27, 1986, a major accident had occurred at an atomic reactor at Chernobyl in the Ukraine
area of the erstwhile Soviet Union. This had resulted in clouds of radioactive smoke over a large area
in Scandinavian countries about 2000 km away, and in the Russian region itself. 1st explosion
occurred at reactor number 4 at the Chernobyl complex occurred on April 26, 1986 and resulted in a
massive and uncontrollable fire.
The explosion was followed by a second explosion on May 5th. Majority of radiation [about
10.19 Bq. of radio nuclides] escaped was released in span of 10 days between 2 explosions. The
explosion and fire was caused by failure of emergency cooling system in the light water graphite
reactor, due to human error.
The explosion and subsequent hot fire (about 2500 0C) blew large amounts of radionuclides high into
the atmosphere. Four main radionuclides released include I-131 [half-life 8.5 years], Cesium-137
[half-life 30 years], C-14 [half-life 5730 years] and Sr-90 [half-life 28 years].
During the first 10 days over 400 million people were exposed to the radiation. In the immediate
vicinity 30 soviet citizens died from radiation poisoning. Over 1,50,000 were evacuated from an area
of radius 30km.
The chronic health impacts include blood abnormalities, hemorrhagic diseases, thyroid changes,
mutagenic and somatic alterations, bone necrosis, skin cancer, failure of reproductive organs etc.
, Bhopal Gas Tragedy
On the fateful night of December 02, 1984 and the early hours of December 03, 1984, more than one
million residents of Bhopal, capital of Madhya Pradesh, India, reported irritation of eyes that quickly
lead to macabre death dancing. A cloud of poisonous gas was released from the union carbide
factory, a pesticide manufacturing plant owned by UNION CARBIDE INDIA Ltd., a subsidiary of
union carbide, USA. The factory was licensed to produce Methyl Iso Cynate, CH3NCO, an
extremely hazardous chemical, which is used in the manufacture of several pesticides like Sevin
Carbaryl and Temik 10-G.Carbon monoxide, obtained by partial oxidation of coal is combined with
chlorine gas in presence of activated carbon to produce phosgene, COCl2. Phosgene gas and methyl
amene combine to form MIC. The product is stored in tanks for further production carbomite
insecticides.
COCl2 + CH3NH2 → CH3NCO +2HCl
Bhopal gas tragedy was as well associated with thick winter fog and thermal inversion, which did
not allow the pollutants to disperse and dilute. It was alleged that MIC is stored up to a purity of
99.5% and 0.1% phosgene is permitted as impurity.
MIC shall not be stored more than 1 month, but due to sheer negligence and ignorance, it was stored
for more than 3 months, as a result of which there was pressure built-up, and the tank couldn’t resist
the extreme pressure generated and exploded releasing as into atmosphere.
About 40 tons of MIC AND 40 kg of phosgene was vaporized and released. In such a scenario, there
is a provision of burning up the gas, by control equipment called flare tower, on whose failure the
gas can be neutralized by caustic soda using vent scrubber. Unfortunately both control devices failed
to work as they were maintained. This was sheer case of human negligence.
MIC is a toxic gas that is denser than air and even at low concentrations is fatal causing death due to
anoxia. MIC is a very reactive chemical that can react with itself unless maintained at a specific
temperature [150C]. Liquid nitrogen was used to maintain this, but device circulating it had failed to
operate and situation worsened.
The next day entire Bhopal railway station was filled with corpses of people who tried to fled the
place, had it not been for presence of 2 lakes that came in way of escaping gas, the disaster would
have been multifold.
Impacts of Air Pollution
Health issues, Soiling of clothes, buildings and plants, Lack of appetite, rapid loss of weight,
lameness, death and Masking of human performance. In plants causes collapse of tissues [necrosis],
Pollution is the introduction of pollutants (chemical substances, noise, heat, light, energy and others)
into the environment which results in deleterious effects of such a nature as to endanger human
health, harm living resources and ecosystems, and impair or interfere with amenities and other
legitimate uses of the environment.
Major forms of pollution
The major forms of pollution are listed below along with the particular pollutants relevant to each of
them:
1. Air pollution, the release of chemicals and particulates into the atmosphere. Common
examples include carbon monoxide, sulfur dioxide, chlorofluorocarbons (CFCs), and
nitrogen oxides produced by industry and motor vehicles. Photochemical ozone and smog are
created as nitrogen oxides and hydrocarbons react to sunlight.
2. Water pollution via surface runoff, leaching to groundwater, liquid spills, wastewater
discharges, Eutrophication and littering.
3. Soil contamination occurs when chemicals are released by spill or underground storage tank
leakage. Among the most significant soil contaminants are hydrocarbons, heavy metals,
herbicides, pesticides and chlorinated hydrocarbons.
4. Radioactive contamination, added in the wake of 20th-century discoveries in atomic physics.
5. Noise pollution, which encompasses roadway noise, aircraft noise, industrial noise as well as
high-intensity sonar.
6. Light pollution, includes light trespass, over-illumination and astronomical interference.
7. Visual pollution, which can refer to the presence of overhead power lines, motorway
billboards, scarred landforms (as from strip mining), open storage of trash or municipal solid
waste.
8. Thermal Pollution is a temperature change in natural water bodies caused by human
influence.
AIR POLLUTION
Definition: the presence in the air of substances generally originating from manmade/natural
activities in concentrations that interfere with the health, comfort, and safety of living beings. It can
be indoor as well outdoor Air pollution. However, our discussion will be restricted to Outdoors type.
CLASSIFICATION OF AIR POLLUTANTS
1. Origin of pollutants
, a. Primary pollutants: emitted directly from source, say, release of SO2 from burning of
coal.
b. Secondary Pollutants: Formed due to interaction of two or more primary and secondary
pollutants, say for instance Acid rain, Ozone, PAN, Smog etc.
2. States of Matter
a. Particulates: composed of solid-liquid --- inert/reactive particles sized 2x10-4 – 500
microns. e.g., dust/smoke
b. Gaseous: SO2, CO, H2S, CH4, CO2 and O3
3. Chemical composition
a. Organic: Aldehydes, Esters, ethers, and amines Inorganic: NOx, SO2, NH3, H2S and O3
b. Physical: Dust, fly ash, spray, pollen, smoke, mist and fumes Chemical:
c. Organic – Inorganic
d. Biological: Protozoa, Bacteria, Fungi and Virus.
Chernobyl Nuclear disaster
April, 27, 1986, a major accident had occurred at an atomic reactor at Chernobyl in the Ukraine
area of the erstwhile Soviet Union. This had resulted in clouds of radioactive smoke over a large area
in Scandinavian countries about 2000 km away, and in the Russian region itself. 1st explosion
occurred at reactor number 4 at the Chernobyl complex occurred on April 26, 1986 and resulted in a
massive and uncontrollable fire.
The explosion was followed by a second explosion on May 5th. Majority of radiation [about
10.19 Bq. of radio nuclides] escaped was released in span of 10 days between 2 explosions. The
explosion and fire was caused by failure of emergency cooling system in the light water graphite
reactor, due to human error.
The explosion and subsequent hot fire (about 2500 0C) blew large amounts of radionuclides high into
the atmosphere. Four main radionuclides released include I-131 [half-life 8.5 years], Cesium-137
[half-life 30 years], C-14 [half-life 5730 years] and Sr-90 [half-life 28 years].
During the first 10 days over 400 million people were exposed to the radiation. In the immediate
vicinity 30 soviet citizens died from radiation poisoning. Over 1,50,000 were evacuated from an area
of radius 30km.
The chronic health impacts include blood abnormalities, hemorrhagic diseases, thyroid changes,
mutagenic and somatic alterations, bone necrosis, skin cancer, failure of reproductive organs etc.
, Bhopal Gas Tragedy
On the fateful night of December 02, 1984 and the early hours of December 03, 1984, more than one
million residents of Bhopal, capital of Madhya Pradesh, India, reported irritation of eyes that quickly
lead to macabre death dancing. A cloud of poisonous gas was released from the union carbide
factory, a pesticide manufacturing plant owned by UNION CARBIDE INDIA Ltd., a subsidiary of
union carbide, USA. The factory was licensed to produce Methyl Iso Cynate, CH3NCO, an
extremely hazardous chemical, which is used in the manufacture of several pesticides like Sevin
Carbaryl and Temik 10-G.Carbon monoxide, obtained by partial oxidation of coal is combined with
chlorine gas in presence of activated carbon to produce phosgene, COCl2. Phosgene gas and methyl
amene combine to form MIC. The product is stored in tanks for further production carbomite
insecticides.
COCl2 + CH3NH2 → CH3NCO +2HCl
Bhopal gas tragedy was as well associated with thick winter fog and thermal inversion, which did
not allow the pollutants to disperse and dilute. It was alleged that MIC is stored up to a purity of
99.5% and 0.1% phosgene is permitted as impurity.
MIC shall not be stored more than 1 month, but due to sheer negligence and ignorance, it was stored
for more than 3 months, as a result of which there was pressure built-up, and the tank couldn’t resist
the extreme pressure generated and exploded releasing as into atmosphere.
About 40 tons of MIC AND 40 kg of phosgene was vaporized and released. In such a scenario, there
is a provision of burning up the gas, by control equipment called flare tower, on whose failure the
gas can be neutralized by caustic soda using vent scrubber. Unfortunately both control devices failed
to work as they were maintained. This was sheer case of human negligence.
MIC is a toxic gas that is denser than air and even at low concentrations is fatal causing death due to
anoxia. MIC is a very reactive chemical that can react with itself unless maintained at a specific
temperature [150C]. Liquid nitrogen was used to maintain this, but device circulating it had failed to
operate and situation worsened.
The next day entire Bhopal railway station was filled with corpses of people who tried to fled the
place, had it not been for presence of 2 lakes that came in way of escaping gas, the disaster would
have been multifold.
Impacts of Air Pollution
Health issues, Soiling of clothes, buildings and plants, Lack of appetite, rapid loss of weight,
lameness, death and Masking of human performance. In plants causes collapse of tissues [necrosis],
