Dr.

Rajesh Roshan Dash

AIR POLLUTION

WHAT IS AIR POLLUTION?

Air pollution is the human introduction of chemicals,

particulate matter, or biological materials that cause
harm or discomfort to humans or other living things.
Air pollution can also cause damages to the natural
environment and to the atmosphere.

Air pollution may be defined as the presence, in the

atmosphere, of one or more contaminants in such
quantities and of such durations as may be or tend
to be injurious to human, animal or plant life, or
property, or which unreasonably
interferes with the comfortable
enjoyment of life or property or
conduct of business.

AIR POLLUTION DUE TO

EXHAUST FROM A CHIMNEY

SOURCES OF POLLUTION

Air pollution can come from a variety of sources

including natural sources and manufactured sources.

Natural sources include forest fires and volcanoes, while cars,

trucks, trains, planes, boats, factories, and power plants
contribute to air pollution through manufactured sources.

Air pollution can even come from smaller, everyday

activities such as dry cleaning, filling your car with gas,
and painting.

Anthropogenic Sources

Human activity, mostly related to burning of

different kinds of fuels.

Natural Sources

As the name itself implies

ANTHROPOGENIC SOURCES

Stationery sources

Mobile sources

Include motor vehicles, marine vessels, aircraft etc.

Point sources

Include smoke stacks of power plants, factories and waste

incinerators, as well as furnaces and other types of fuelburning heating devices.

Include include stationary sources such as power plants,

smelters, industrial and commercial boilers, wood and pulp
processors, paper mills, industrial surface coating facilities,
refinery and chemical processing operations, and petroleum
storage tanks

Nonpoint sources

Include motor vehicles, marine vessels, aircraft, Agriculture,

Waste management, engines for construction, plants emit
some VOCs

ANTHROPOGENIC SOURCES

Agricultural and Forestry management

Paint, Varnishes, Aerosol sprays

All these and also other chemicals like hair sprays etc.
emit harmful chemicals.

Landfills

Various types of hazardous chemicals from different

germicides and pesticides, dust and dirt at the time of
swiping.

Waste deposition in landfills,

which generate methane, which
mixes with air and may form
explosive mixtures.

Military

Nuclear weapons, toxic gases, germ

warfare, rocketry etc. also causes air pollution

NATURAL SOURCES

Lack of Vegetation

Digestion of food

Radon gas produced from the radioactive

decay of Radium, within the earths crust.

Wildfire

Methane produced by digestion of food by cattle.

Radioactive decay

Dust from a large area of land

with little or no vegetation.

Smoke and Carbon monoxide from wildfire.

Volcanic Activities

Produces sulphur, chlorine, ash

particulates, fumes etc. which pollute air.

POLLUTANTS

Natural Contaminants

Aerosols/Particulates

Fog, Pollen Grains, Bacteria, Products from

volcanic erruptions, Forest fires
Dust, Smoke, Mist, Fog, Fume, Haze, Soot

Gases and Vapours

Sox, NOx, O3, COx, Halogen, Organic (HC,

Aldehydes), Radio Active Gases (Radon,
Thoron)

POLLUTANTS

A pollutant is known as a substance in the air

that can cause harm to humans and the
environment.
Pollutants can be in the form of solid particles,
liquid droplets, or gases.
In addition, they may be natural or man-made.

Pollutants can be classified into 2 types : Primary Pollutants

directly emitted from a process.

Secondary Pollutants

formed in the air when primary pollutants react or

interact.

Primary (1) pollutants are put directly into the air

as a result of a given process. Examples:

carbon monoxide,
nitrogen oxides,
sulfur oxides,
particulate matter, and
Hydrocarbons
Halogen Compounds

Secondary (2) pollutants are formed in the air

when chemical reactions change the primary
pollutants. Examples:

Photochemical smog
Ozone
PAN (Peroxy Acetyl Nitrate)
Fomaldehyde
acid rain

CARBON MONOXIDE (CO)

Carbon monoxide is an odorless, colorless gas.

It is formed when the carbon in fuels does not
completely burn.

Vehicle exhaust contributes roughly 60% of all carbon

monoxide nationwide, and up to 95% in cities

Carbon monoxide thats produced by humans is

localized and comes in periods of high emission
rates (during rush hours for example).
Carbon monoxide levels typically are highest
during cold weather because cold temperatures
make combustion less complete and cause
inversions that trap pollutants close to the ground.

NITROGEN OXIDES (NOX)

The three main nitrogen oxides present in the air

are: nitric acid (NO), nitrogen dioxide (NO2), and
nitrous oxide (N2O).
Nitric oxide and nitrogen dioxide arise from the
burning of biomass and fossil fuels.

NO and NO2 are important in the formation of both acid

precipitation and photochemical smog (ozone), and
causes nitrogen loading.

Nitrous oxide comes from nitrogen based

fertilizers, deforestation, and biomass burning.

N2O is important in the

greenhouse effect and causes
nitrogen loading.

SULFUR OXIDES (SOX)

Sulfur oxide emissions from man-made

consists primarily of sulfur dioxide.

During emission and while in the atmosphere, gaseous sulfur

dioxide can become oxidized to form sulfate (SO4)2-

Sulfur dioxide is produced by combustion of sulfurcontaining fuels, such as coal and fuel oils.

Power plants and factories emit 90-95% of the sulfur dioxide in

the United States

sources

Almost 60% of these emissions are released by tall smoke stakes

which enables emissions to travel long distances

Sulfur dioxide and nitric oxide form secondary

pollutants such as nitrogen dioxide, nitric acid vapor,
and droplets containing solutions of sulfuric acid,
sulfate, and nitrate salts.

These chemicals then descend to the earths surface in wet form

as rain or snow and in dry from as fog, dew, or solid particles

This is known as acid deposition or acid rain

PARTICULATE MATTER

Particulate matter pollution can also be referred to

as black carbon pollution or just particle
pollution.
Particles are released into the air from burning
fuel for energy.

Major sources include exhaust from burning fuels in

automobiles, homes, and industries

Particulate matter comes in a range of sizes

Fine particles are less than 2.5 micrometers in

diameter
Course dust particles are between 2.5 and 10
micrometers in diameter

PARTICULATES

Dust (3m-100m)

Smoke (0.01m-0.2m)

CONTD

Mist (40m-500m)

Fog (1m-40m)

CONTD

Fumes (<1m)

Soot (>1m)

HYDROCARBONS

Hydrocarbons tend to exist as extremely

volatile liquids.
Hydrocarbons can come from natural sources
and anthropogenic (man-made) sources.

Natural sources of hydrocarbons arise from

geothermal activity, bacterial composition of organic
matter, and from trees and plants
Two examples of anthropogenic sources are creation
of petroleum and incomplete combustion of fuel oil

Carbon dioxide (CO2)

Greenhouse gas, emitted from combustion.

Volatile Organic Compounds (VOCs)

Methane, Benzene, Toluene, Xylene,
Butadiene.

1,3-

Ammonia (NH3)
Hazardous chemical,
agricultural processes.

from

mainly

emitted

 Halogen

Compounds/Chlorofluorocarbons
Emitted from phosphate fertiliser, alluminum
industry, brick plant

Toxic

metals
Lead(Pb), Cadmium(Cd), Copper(Cu).

Radioactive

Nuclear
elements.

pollutants
explosions,

decay

of

radioactive

PHOTOCHEMICAL SMOG

Smogs unpleasant properties result from

the irradiation by sunlight of hydrocarbons
caused primarily by unburned gasoline
emitted
by
automobiles
and
other
combustion sources.
The products of photochemical reactions
include volatile organic compounds, ozone,
aldehydes, ketones, peroxyacetyl nitrate,
organic acids, and other oxidants.

PEROXY ACETYL NITRATE (PAN)

Formed by combination of HC, NOx, SO2 and
VOCs.

INDUSTRIAL SMOG

This type of smog is created by burning

coal and heavy oil that contain sulfur
impurities in power plants and industrial
plants.
The smog consists mostly of a mixture of
sulfur dioxide and fog.
Suspended droplets of sulfuric acid are
formed from some of the sulfur dioxide,
and a variety of suspended solid particles.

OZONE

Ozone is one of the primary components of

photochemical smog.
Ozone (a secondary pollutant) is a gas composed
of three atoms of oxygen.
This secondary pollutants formation results from
the sunlight initiated oxidation of volatile organic
compounds (VOCs) in the presence of nitrogen
oxides.
It occurs in the Earths upper atmosphere and at
ground level. It can be good or bad, depending on
where its found.

Good ozone occurs naturally 6-30 miles above the

Earths surface, where it forms a protective layer that
shields us from the suns harmful ultraviolet rays
Bad ozone occurs in the Earths lower atmosphere, near
ground level

This is formed when pollutants emitted by cars, power plants, industrial

boilers, refineries, and chemical plants react chemically in the presence
of sunlight
This ozone causes eye irritation, impaired lung function, and damage to
trees and crops.

OZONE: ITS TWO PROBLEMS

(1)

Certain pollutants deplete

ozone in the stratosphere,
exposing us to unhealthy
levels of ultraviolet radiation.
- Ultraviolet radiation is known to
cause skin cancer and has
damaging effects on plants and
wildlife

(2)

Human-related emissions are

spurring the formation of
harmful ground-level ozone,
which is a major contributor
to smog.

Overview of Air Pollution

HEALTH EFFECTS

Chronic
Acute (Example: Methyl Isocyanate from Pesticide
Industry in1984 in Bhopal)

MAJOR EFFECTS DUE TO AIR

POLLUTION

Eye, Nose, Throat, Respiratory irritation (NOx, COx, O3)

Bad smell and odour due to H2S, NH3, mecerptants

Increase in mortality and morbidity rate due to toxic pollutants

Asthmatic attack due to pollens and dusts

Bronchitis asthma due to long term exposure to SO2, NO2,

Particulate, Smog

Cardiovascular and pulmonary diseases due to CO

Carcinogenic agents cause cancer (3,4-benzyrene)

Silicosis, asbestosis due to specific dust particles

Poisoning due to heavy metal particles

Cancer and death, mutational change due to radioactive substance

Skin problem due to allergic agents (organic material, pollen, animal

hair, feather, yeast, bacteria)

SUSPENDED PARTICULATE MATTER

Characteristics :

Solid particles like dust, smoke and fumes

Liquid particles like mist and fog

Source

Dust storms
Cigarette smoke
Smoke from burning of garbage, fossil fuel
Fumes like those of zinc or lead

SUSPENDED PARTICULATE MATTER

Health effects

Effects on breathing and respiratory systems

Aggrevation of existing respiratory and cardiovascular
diseases
Eye and throat irritation, Headache, Lightheadedness,
Nausea
Alteration of bodys defence systems against foreign
material
Damage to lung tissues
Carcinogenic effects and premature mortality
Perception of unpleasant odors
Asthmatic attacks in children

SULPHUR DIOXIDE

Characteristics:

Colourless gas
Taste threshold at 0.3 ppm
Odour threshold at 0.5 ppm

Source

Combustion of oil and coal in power

stations and automobiles

SULPHUR DIOXIDE
Health Effects

Effects on breathing and Respiratory illness

(Exposure to high concentrations for short periods of time can
constrict the bronchi and increase mucous flow, making breathing
difficult).
Impair the respiratory system's defenses against foreign particles
and bacteria, when exposed to concentrations less than 6 ppm for
longer time periods
(Children, the elderly, those with chronic lung disease, and
asthmatics are especially susceptible to these effects).
Aggrevation of existing respiratory and cardiovascular diseases
Leads to photochemical smog in some areas by oxidising the
hydrocarbons
Apparently enhance the harmful effects of ozone. (Combinations of
the two gases at concentrations occasionally found in the ambient
air appear to increase airway resistance to breathing.)

Sulfur dioxide easily injures many plant species and varieties, both
native and cultivated. Some of the most sensitive plants include
various commercially valuable pines, legumes, red and black oaks,
white ash, alfalfa and blackberry. The effects include:

Visible injury to the most sensitive plants at exposures as low as 0.12

ppm for 8 hours.

Visible injury to many other plant types of intermediate sensitivity at

exposures of 0.30 ppm for 8 hours.

Positive benefits from low levels, in a very few species growing on

sulfur deficient soils.

Increases in sulfur dioxide concentrations accelerate the corrosion of

metals, probably through the formation of acids. (SO 2 is a major
precursor to acidic deposition.) Sulfur oxides may also damage stone
and masonry, paint, various fibers, paper, leather, and electrical
components.

Increased SO2 also contributes to impaired visibility. Particulate sulfate,

much of which is derived from sulfur dioxide emissions, is a major
component of the complex total suspended particulate mixture.

CARBON MONOXIDE (CO)

Characteristics :

Colourless
Odourless
Tasteless

Source :

Incomplete combustion of coal and oil

(diesel, petrol, etc.) fuels

CARBON MONOXIDE

Health Effects

Reduces oxygen delivery to organs and

tissues
At elevated concentrations, CO impairs
visual perception, manual dexterity, and
mental ability
Also causes drowsiness and headaches

NITROGEN OXIDES (NOX)

Characteristics :

NO is a reddish-brown highly reactive gas

Odour threshold is at about 0.2 ppm

Source

High temperature combustion in

automobiles (cars etc.) and in thermal
power stations

NITROGEN OXIDES (NOX)

Health effects
NO plays a major role in tropospheric ozone formation
NO2 irritates the lungs, causes bronchitis and pneumonia,
lowers resistance to respiratory infections.
Asthmatics
are most susceptible and increases
susceptibility to viral attacks
Short-term exposure at concentrations greater than 3
parts per million (ppm) can measurably decrease lung
function.
Concentrations less than 3 ppm can irritate lungs.
Concentrations as low as 0.1 ppm cause lung irritation
and measurable decreases in lung function in asthmatics.
Long-term lower level exposures can destroy lung tissue,
leading to emphysema.
Children may also be especially sensitive to the effects of
nitrogen oxides.

Seriously injure vegetation at certain concentrations. Effects

include:

Bleaching or killing plant tissue.

Causing leaves to fall.

Reducing growth rate.

Deteriorate fabrics and fade dyes.

Corrode metals (due to nitrate salts formed from nitrogen oxides).

Reduce visibility.

Oxides of nitrogen, in the presence of sunlight, can also react with

hydrocarbons, forming photochemical oxidants or smog.

Also, NOx is a precursor to acidic precipitation, which may affect

both terrestrial and aquatic ecosystems.

LEAD

Characteristics:

Colourless vapour
Consumed through inhalations

Source

Leaded petrol used by cars

Ingestion and inhalation may also occur
from food, water, soils or dust

LEAD

Health effects

Causes seizures, mental retardation and

behavioral diseases
Foetuses, infants and children are especially
susceptible to low doses resulting in
disorders of central nervous system
High blood pressure and heart diseases
Anemia
Kidney damage

OZONE (O3)

Characteristics :

Colourless gas
Threshold odour is at 0.3 ppm

Source

Secondary pollutant produced by

photochemical pollution
Largest constituent of photochemical smog,
PAN etc.

OZONE (O3)
Health effects :
Ozone acts as a powerful respiratory irritant at the
levels frequently found in most of the nation's urban
areas during summer months.
Ozone exposure may lead to:
Shortness of breath.
Chest pain when inhaling deeply.
Wheezing and coughing.
Long-term, repeated exposure to high levels of
ozone may lead to large reductions in lung function,
inflammation of the lung lining, and increased
respiratory discomfort.
Coughing, sneezing, chest pain, and pulmonary
congestion

Summary of Major Pollutant

FACTORS AFFECTING HEALTH

EFFECT

Nature of pollutant
Concentration of pollutants
Duration of exposure
State of health of receptor
Age group receptor

EFFECT ON STRUCTURES AND MATERIALS

Abrasion
Deposition and removal
Chemical attack
Corrosion

EFFECT ON PLANTS

Necrosis (Killing or collapse of tissues)

Chlorosis (Loss or reduction of green
plant pigment)
Abscission (Dropping of leaves)
Epinasty (Downward curvature of
leaves)

STANDARDS TO AIR POLLUTION

This nation-wide programe was initiated in 1984.

As on March 31, 1995, the network comprised 290
stations covering over 90 towns/cities distributed
over 24 States and 4 Union Territories.
The National Ambient Air Quality Monitoring
(NAAQM) network is operated through the respective
States Pollution Control Boards, the National
Environmental
Engineering
Research
Institute
(NEERI), Nagpur and also through the CPCB.