POLLUTION

What do you understand by Pollution?

 Historical Factors

Economic

Political Social

Scientific
 What is a Pollutant?
• A substance that Pollutes - causes Pollution
• The threshold level
• Dangerous - affects living beings adversely
• Characteristic - Natural or Anthropogenic
• Classi cation —
• Primary and Secondary Pollutants
• Quantitative and Qualitative Pollutants
• Biodegradable, Slowly Biodegradable and Non
Biodegradable
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Classification of Pollution
AIR POLLUTION

NOISE POLLUTION

WATER POLLUTION

THERMAL POLLUTION

SOIL POLLUTION - LAND DEGRADATION

RADIOACTIVE POLLUTION

PLASTIC POLLUTION

LIGHT POLLUTION
AIR POLLUTION
Is Air Pollution a Modern Phenomenon?
The Industrial Revolution of 18th Century
In the Words of Wordsworth

… I grieve, when on the darker side

Of this great change I look; and there behold

Such outrage done to nature …

The Two Major events in Air pollution History
Release of pollutants into the air which are
detrimental to human health and the planet
as a whole

• Under Air Pollution Act 1981 - Air

Pollutant means — solid, liquid or gaseous
substance - also includes Noise
Sources of Air Pollution
Types of Air Pollution
Important Air Pollutants
Particulate Matter
Particulate Matter
 Particulate Matter
• A mixture of solid particles and liquid droplets
found in the air

• Particulate matter pollution does not

include gas pollutants like ozone and
NO2

• Includes both organic and inorganic particles,

such as dust, pollen, soot, smoke, and liquid
droplets

• Sources: construction sites, unpaved roads,

elds, smokestacks or res
PM2.5: ne inhalable particles, with diameters that
• WHO - PM 2.5 can penetrate through the are generally 2.5 micrometers and smaller.
lungs and further enter the body through the
blood stream. PM10: inhalable particles, with diameters that are
generally 10 micrometers and smaller; and
• Studies have shown PM 10 can penetrate
lungs and enter the bloodstream
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 UPSC CSE
Prelims 2022
Black carbon (Soot)

● Part of PM 2.5
● Formation - Incomplete combustion of
Fossil fuels
● Short-lived - Days to weeks
● Warming impact - 500 to 1500 times than
CO2
● Impact on Cryosphere - the albedo
Ice Albedo Feedback
Brown carbon

● Brown smoke from combustion of

organic matter
● Major source —> Biomass burning
● Coexists with Black carbon
● Also warms the atmosphere
 Tarballs found in Himalayas

● Small, light absorbing

carbonaceous particles formed from
brown carbon
● Speeds up glacial melt
● Reason —> Biomass burning in
Indo-gangetic plain
● Long-range transport
(FLYASH)
 Flyash
• Finely divided residue that results from the combustion of
pulverized coal

• Emitted along with ue gas - collected using a Electrostatic

precipitator

• Composition: Beryllium, Arsenic, unburnt Carbon, Silicon

Oxides, Dioxins, aluminium oxide, ferric oxide, calcium
oxide, etc

• Applications - Portland cement concrete (PCC), soil and

road base stabilization, admixtures in concrete etc

• Harmful Effects - Toxic Air and water pollutant

• Leaches heavy metals into groundwater
• Cognitive defects, Nervous system damage, Birth
defects etc
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 Flyash Utilisation
• National Thermal Power Corporation:
• Collaboration with Cement manufacturers
around the country to supply Fly Ash

• Setting up of Fly Ash brick manufacturing Plants

at its Coal based Thermal Power Plants

• Pradhan Mantri Awas Yojana (Urban) has focused on

new construction technologies such as using y ash
bricks

• ASHTRACK - web portal and mobile app for

monitoring of y ash generation and utilization

• Reduction of GST on Fly ash and its products to 5%

• Maharashtra’s(1st state) - Fly ash utilisation policy
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Flyash Management & Utilisation Mission

• ‘Unscienti c handling and storage’ of the y ash by

coal thermal power stations

• Direction by NGT - to constitute a mission to oversee the

management & utilisation of Flyash

• Monitoring the disposal of annual stock of

unutilised y ash

• Jointly headed by Secretaries of - MoEFCC & Ministry

of Coal
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 Carbon Monoxide
• Colourless and odourless gas
• Major Source — Burning of Fossil Fuels
• Leads to fatal conditions - generally in enclosed indoor
spaces

• CO binds with RBC’s depriving it of Oxygen

• Formation of Carboxyhaemoglobin
• Exposure to CO - Headache, Nausea, Dizziness etc
• At high concentration - Unconsciousness & Death
• Not a direct GHG - but contributes to formation of,
• Tropospheric Ozone - a GHG
• Methane - 28 times more potent than CO2
(Will be dealt in Climate Change)
 Sulphur-Di-Oxide
• A colourless, reactive air pollutant with a strong
pungent odour
• Major Sources:
• Natural - Volcanoes
• Anthropogenic - Fossil Fuel Combustion - Thermal
power plants, Vehicular emissions, Petroleum
re ning, Paper Industry, etc
• Harmful Effects:
• Respirator y problems suc h as bronc hitis,
Cardiovascular disease, Increases risk of Stroke
etc
• Major contributor to Acid Rain
• Causes Haze & reduces visibility
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Lichens —

Good Indicators of
Sulphur-di-oxide
Pollution.
• India - Top spot for the 5th consecutive time - 21% of
global emissions of SO2
• Coal based Thermal plants - major contributor
•S i n g r a u l i ( M P ) , N e y v e l i , J h a r s g u d a ( O d i s h a ) ,
Ramagundam (Telangana) etc
Nitrogen
Oxides
• A colourless, reactive air pollutant with a strong pungent odour
• Major Sources:
• Natural - Volcanoes, Burning of wood & Biomass
• Anthropogenic - Fossil Fuel Combustion - Thermal power plants, Vehicular emissions,
diesel engines etc
• Nitric Oxide - Colourless gas which gets oxidised to form NO2
 Effects of NO2 Pollution
• Health effects: Respiratory ailments, asthma, affects lung
function, increasing risk of Cardiovascular disease etc
• Contributes to Formation of Tropospheric Ozone
• Photochemical smog formation
• Acid Rain
Ozone & Oxides of Nitrogen
Polycyclic Aromatic Hydrocarbons
• Organic compounds which include only carbon and
hydrogen with a structure of fused rings

• Class of chemicals that occur naturally in coal, crude oil,

and gasoline

• Produced when coal, oil, gas, wood, garbage, and tobacco

are burned

• Eg: Naphthalene, Pyrene, Styrene etc

• Naphthalene is a manmade PAH
• Exposure - Breathing air contaminated with motor vehicle
exhaust, cigarette smoke, wood smoke, or fumes from
asphalt roads

• Travel through the atmosphere as a gas or attached to dust

particles

• PAH’s - Toxic, Mutagenic & Carcinogenic

Mechanism of Transport
 Per- and
Polyfluoroalkyl
Substances
(PFAs)
 PFA’s
•Man-made chemicals
•Application: Nonstick cookware, water-repellent
clothing, stain-resistant fabrics, cosmetics, re ghting
foams

•Migrates to the soil, water, and air - do not break

down easily - FOREVER CHEMICALS

•The bond between Fluorine and Carbon is very

strong that resists breaking down

•Effects on health - decreased fertility, developmental

effects in children, interference with body hormones,
increased cholesterol levels, and increased risk of some
cancers

•Dif culty to build antibodies af ter being

vaccinated
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• Incineration - Only breaks down completely at
incineration temperatures around 1,500 degrees
Celsius - Energy Intensive process

• Supercritical Water Oxidation - High temperatures

and pressures change the state of water, accelerating
chemistry in a way that can destroy hazardous
substances

• Plasma reactors - which use water, electricity, and

argon gas to break down PFAS

• Filtration with activated carbon in the rain water

harvesting system
 Volatile
Organic
Compounds
 Benzene Pollution
• Colourless or light-yellow chemical that is liquid at room
temperature - Highly ammable

• Application - plastics, resins, nylon, synthetic bres,

lubricants, rubbers, dyes, detergents, drugs, and pesticides

• Sources:
• Natural sources - Volcanoes and Forest res.
• Anthropogenic - Natural part of crude oil, gasoline, and
cigarette smoke.

• Indoor sources - from products such as glues, paints,

furniture wax, and detergents.

• Health effects - Damages nervous system, Carcinogen,

Immune system damage, affects bone marrow resulting in
low RBC production
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EFFECTS OF AIR POLLUTION
• ACID RAIN
• OCEAN ACIDIFICATION
• ASIAN TROPOPAUSE AEROSOL LAYER (ATAL)
• OZONE LAYER DEPLETION
• FOGHOLES
• SMOG FORMATION
ACID RAIN
 ACID RAIN

• Any form of precipitation with acidic components, such as sulphuric or nitric acid
• The SO and NO - react with water —- Forms Sulphuric acid & Nitric acid
2 X

• Forms:
• Wet deposition - Acids formed in the atmosphere fall to the ground mixed with rain,
snow, fog, or hail
• Dry deposition - Acidic particles and gases can also deposit from the atmosphere in
the absence of moisture
 Effects of Acid Rain
On Vegetation:
• Disturbs the pH of the soil - affecting plant growth, soil
microorganisms distribution, etc
• Leaves and needles of trees - cuticle damage
• Damages roots, slows growth and makes plants weaker
• Leaches Calcium - cell wall in plants
• Mobilisation of Aluminium which curbs root growth and
prevents water uptake
Aquatic Ecosystem:
• Alters the water chemistry, Kills sensitive crustaceans,
affects reproductive cycle etc
• Harms phytoplankton - upsets food chain balance
 Effects of Acid Rain
On Animals:
• Health problems in humans - Eye irritation, Asthma,
Skin Cancer

On structures:
• Affects artistic, historical and cultural heritage
• Corrosion of Metals
• Marble Cancer - Eg: Taj Mahal
AEROSOLS
Asian Tropopause Aerosol Layer

ATAL
 Asian Tropopause Aerosol Layer
•A con ned area of Aerosol layer covering South Asia
during South West Monsoon
•Extends from Eastern Mediterranean Sea to West China
•Formation: Convective transport of aerosols from the lower
atmosphere to the Upper Troposphere & Lower Stratosphere
•Composition:
•Predominantly Sulphates originating from S.Asia
•Also includes Black Carbon, Dust etc
•Effects:
•Scattering of Insolation Negatively affects the
•Blocks sunlight from reaching the ground Monsoon resulting
•Cooling effect on Earth Surface decease in Rainfall
•Weakens the Convection cell
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OZONE LAYER
DEPLETION
DOBSON UNITS - most common unit for measuring ozone concentration.
One Dobson Unit is the number of molecules of ozone that would be required to create a layer
of pure ozone 0.01 millimeters thick at a temperature of 0 degrees Celsius and a pressure of 1
atmosphere
Importance of Ozone Layer
Ozone Depleting Substances
 •Ant arctic Ozone Hole - Severe deple tion of
Antarctic Ozone Hole stratospheric ozone in late winter and early spring

•Formation - each year in the months of September,

October and November

•Reason? - Set of special meteorological and chemical

conditions that arise at the South Pole

•Steps:
•Strengthening of Polar Vortex in Winter which
isolates the Polar Stratosphere

•Drop in Temperature to around (-80℃)

•Formation of Polar Stratospheric Clouds
•PSC’s convert stable chlorine reservoir species to
radicals that catalytically destroy ozone
Role of Polar Stratospheric Clouds
•PSC’s - called Nacreous clouds due to their
iridescence
•Iridescence caused by diffraction & interference
due to its similar sized ice crystal composition
•Wave clouds - sheet-like formations gradually
undulate and extend
•Forms in the winter polar stratosphere - at altitudes of
15 to 25 km
•Forms only at extremely low temperatures @ -80℃
•More commonly observed near South Pole than
North
•Act as a medium for converting reservoir forms of
chlorine to the most reactive form which depletes
ozone
 Ozone Layer Conservation
•Vienna Convention for the Protection of the Ozone Layer
•Adopted in 1985 - entered into force in 1988
•Convention in itself did not have any legally binding targets
•2009 - achieved universal rati cation
•India rati ed in 1991 - MoEFCC is in charge - establishment of
Ozone cell
•It had provision for Protocols to set legally binding targets
•1987 - Adoption of Montreal Protocol on Substances that Deplete
the Ozone Layer
•Entered into force in 1989 - India joined in 1992
•Ozone Secretariat @ UNEP
•Multilateral Fund - UNEP, UNDP, UNIDO, World Bank
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 KIGALI AMENDMENT

● 2016 Amendment to Montreal protocol to phase out HFC’s - 2019 entered into force
● 80% reduction in consumption of HFC by 2047
● India has ratified - freeze consumption by 2028
● Legally binding commitment
● Common but differentiated responsibilities - 3 groups
● India in 3rd group
Tropospheric Ozone

● Surface level Ozone

● Air pollutant - Unhealthy to Breathe
● Short-lived Climate pollutant
● Secondary Pollutant
● Result of Air pollution - photochemical
reaction involving Carbon monoxide, NOx,
VOCs
● Causes Crop Damage
FOGHOLES
 Fog Holes
•Fog is a visible aerosol comprising tiny water
droplets or ice crystals suspended in the air at or
near the Earth's surface
•Formation - Low Temperature + High Humidity
•Fog Hole - a variable sized open patch in an
extensive fog cover
•Cause —
•Lack of Vegetative Cover —> lower humidity +
lack of microclimate regulation
•Urban Heat Island
•Recent Study - using data from MODIS - NASA
•More prominent fog hole over New Delhi
•Reduction in 50% frequency in fogs
SMOG FORMATION
 What is Smog?
•Smog is a type of Air Pollution,
•Combination of Smoke + Fog + Harmful pollutants
•Forms close to the ground level
•Harmful for living beings when inhaled

•Historically a byproduct of Industrial Revolution - Burning of Coal

•Present day - predominantly caused by anthropogenic emissions

•Types:
•Winter Smog - London Smog - Sulphurous Smog
•Summer Smog - Los Angeles Smog - Photochemical smog
 Sulphurous Smog
•Also known as Winter Smog or London Smog or Classical
Smog
•Major Contributor - Burning of fossil fuels which releases
harmful particulate matter and pollutants like Sulphur di
oxide
•PM combine with Fog = SMOG

•Major contributing meteorological conditions:

•Temperature Inversion
•Limited Advection

•London Smog of 1952 - led to the deaths of 4000 people

 Photochemical Smog
•Also known as Summer Smog or Los Angeles
Smog - Distinguished by the Brown Haze
•A modern phenomenon in Urban areas - High
level of Vehicular & Industrial Emissions
•Formation of Smog - contributed by,
•Primary Pollutants - NOx, VOC’s, CH4,
CO etc
•Secondary Pollutants - Tropospheric
Ozone, Peroxyacetyl nitrates, Aldehydes etc
•Meteorological conditions - Presence of Sunlight +
Warmer Temperature + Slow wind speed
•Results in adverse health effects - Lung tissue
damage, Protein structure damage by PAN’s etc
Photochemical Smog formation