Air pollution

1. Dr Fayaz A. Malla
Assistant Professor, Environmental Sciences
GDC Tral
Higher Education Department, Govt. of J&K
Email: ismifayaz@gmail.com

2. • The word pollution comes from the
Latin word, Pollutionem, which
means to soil or defile.
• However, it was not initially used in
reference to the environment, but to
the human soul.
• To some of us environmentalists,
polluting the environment can feel
an awful lot like polluting our souls.

3. Pollution is classified into point source or
nonpoint source pollution.
A point source of pollution is a single identifiable
source of air, water, thermal, noise or light pollution.
A point source has negligible extent, distinguishing
it from other pollution source geometries.
Nonpoint source (NPS) pollution is a term used to
describe pollution resulting from many diffuse
sources, in direct contrast to point source pollution,
which results from a single source. Nonpoint source
pollution generally results from land runoff,
precipitation, atmospheric deposition, drainage,
seepage, or hydrological modification (rainfall or
snowmelt) where tracing the pollution back to a
single source is difficult.

4. Types of Pollutant
Based on their Nature
Primary Pollutants: These pollutants remain
in environment in the same form in which
they were released. E.g., Carbon monoxide,
Sulphur dioxide
Secondary Pollutants: These are formed by
modification of primary pollutants. E.g.,
nitrogen oxides, hydrocarbons react
photochemically to form ozone, aldehydes
and peroxyacyl nitrate (PAN)

5. Types of Pollutant
Based on their Degradability
Degradable Pollutants: These are the pollutants
which are broken down into smaller harmless
products by microorganisms like bacteria and fungi.
Non-degradable Pollutants: These are the
pollutants which cannot be converted into harmless
state by chemical or biological degradation. These
are also known as conservative or persistent
pollutants. E.g., plastic bottles, polythene bags etc.

6. • Pollution may be natural or anthropogenic.
• Natural pollution is caused by processes
like forest fire, volcanic eruptions,
landslides.
• Anthropogenic pollution is caused by
human activities like smoking, stone
crushing fossil fuel brining.
Types of Pollution
• Air pollution
• Water Pollution
• Soil Pollution
• Thermal Pollution
• Marine Pollution
• Noise Pollution
• Radioactive pollution

8. INTRODUCTION
• Air is essential for life itself, without it we
could survive only a few minutes.
• It constitutes immediate physical environment
of living organisms
• The atmosphere is layered in to four distinct
which are: Troposphere, stratosphere,
mesosphere, and thermosphere.

9. What is air
Pollutant?
• A pollutant is a substance which has harmful
effects on human life, vegetation, animals and
environment.
• It can be a substance (fly ash), chemical (oxides
of Sulphur and nitrogen) or a factor (noise, heat)
• Air pollution consists of gases, liquids, or solids
present in the atmosphere in high enough levels
to harm humans, other organisms, or materials.

10. Normal
components of
our atmosphere
• Nitrogen - 78.1%
• Oxygen - 20.9%
• Carbon dioxide - 0.03%
• Everything else - 0.07%
• noble gases (krypton, xenon,
argon, helium)
• methane
• sulfur dioxide

11. Air pollution is defined as contamination of air with harmful toxic gases and particulate matter. It
can also be defined as the presence of foreign materials in air at a concentration which interferes
with human health safety and is injurious to vegetation, animals and other objects.
Air
Pollutants
Hydroca
rbons
CO
CO2
SO2
H2S
H2
No.
NO2
PM
Pb
Zn
Hg
Cr
CFCs
Smog

12. Sources of Pollution
• Point Sources
• Non-Point Sources
• Primary Pollutants
• Secondary Pollutants
• Natural Sources
– Larger than anthropogenic sources

13. Carbon Monoxide
• Source:
– burning fossil fuels
• Replaces oxygen in
blood stream
– Bonds to hemoglobin
• Only dangerous in
high concentrations

14. Nitrogen Oxides: Photochemical Smog
• Source: Automobiles (burning gasoline)
• NO2 + UV  O3 + Nitrates
• Yellow-brown color, sweet smell

15. Sulfur Oxides: Industrial Smog
• Source: Coal-fired industry, electric
• SO2 + UV  O3 + Sulfates
• Gray-air smog, colored by soot

16. Sulfur & Nitrogen Oxides:
Acid Rain
• Source: Coal-fired
industry, electric
• Normal Rain pH 5.6
– CO2 + H2O  H2CO3
(normal)
– NO2 + H2O  HNO3
(contributes)
– SO2 + H2O  H2SO4 (strong
acid)
• Secondary pollutant
• Limestone acts as a

17. Effects of Acid Deposition
• Human respiratory illness
• Leach toxic metals from
pipes to water
• Damage building materials
• Lakes – acid shock
– Release Al3+ into water –
asphyxiate fish
– Dissolve nutrients - reduce
algal growth
• Plants and soils
– Weakens trees, competition
with mosses
– Acids leach minerals from soil

18. Ground-level Ozone
• Source: burning fossil fuels
• Secondary Pollutant!
– Formed from rxns with UV
• Health Effects
– Chest pain, coughing, throat irritation,
congestion
– Worsen respiratory disease (bronchitis,
asthma, etc.)
• Environmental Damage
– Damage leaves, reduce crop yields

19. Lead
• Source: industry, waste incinerators
– Regulations removed lead from gasoline
• Toxicant, accumulates in bones
– Neurological, kidney, immune and
reproductive systems

20. Particulate Matter
• Source: dust, fires, volcanoes, fossil
fuels
• Regulated PM10 and PM2.5
– Smaller than 10 um (thickness of one hair
strand)
• Health effects

21. Thermal Inversions
• Warm air on top of a layer of cool air near
surface
• Prevents
pollutants
from rising
& dispersing

22. Reducing Pollution
• Carbon Monoxide
– CO detectors in homes
• Nitrogen Oxides
– Catalytic converters and regulations on
vehicles
• Sulfur Oxides
– Scrubbers on smokestacks
• Ozone
• Lead
– Unleaded gasoline, removed from paints
• Particulates
– Spray mines and construction with water

23. Impact
of Air
Pollution
on
Health
Air pollution is a major environmental health problem affecting the
developing and the developed countries alike.
The effects of air pollution on health are very complex as there are
many different sources and their individual effects vary from one to
the other.
It is not only the ambient air quality in the cities but also the indoor
air quality in the rural and the urban areas that are causing concern.
In fact, in the developing world the highest air pollution exposures
occur in the indoor environment.
Air pollutants that are inhaled have serious impact on human
health affecting the lungs and the respiratory system; they are also
taken up by the blood and pumped all round the body.
These pollutants are also deposited on soil, plants, and in the water,
further contributing to human exposure.

24. Health Impact of Specific Air Pollutants
• Tobacco smoke. Tobacco smoke generates a wide range of harmful chemicals and is a major cause
of ill health, as it is known to cause cancer, not only to the smoker but affecting passive smokers
too. It is well-known that smoking affects the passive smoker ranging from burning sensation in
the eyes or nose, and throat irritation, to cancer, bronchitis, severe asthma, and a decrease in lung
function.
• Biological pollutants. These are mostly allergens that can cause asthma, hay fever, and other
allergic diseases.
• Volatile organic compounds. Volatile compounds can cause irritation of the eye, nose and throat.
In severe cases there may be headaches, nausea, and loss of coordination. In the longer run, some
of them are suspected to cause damage to the liver and other parts of the body.
• Formaldehyde. Exposure causes irritation to the eyes, nose and may cause allergies in some
people.

25. • Radon. A radioactive gas that can accumulate inside the house, it originates from the
rocks and soil under the house and its level is dominated by the outdoor air and also to
some extent the other gases being emitted indoors. Exposure to this gas increases the
risk of lung cancer.
• Ozone. Exposure to this gas makes our eyes itch, burn, and water and it has also been
associated with increase in respiratory disorders such as asthma. It lowers our
resistance to colds and pneumonia.
• Oxides of nitrogen. This gas can make children susceptible to respiratory diseases in
the winters.
Health Impact of Specific Air Pollutants

26. • Carbon monoxide. CO (carbon monoxide) combines with haemoglobin to lessen the
amount of oxygen that enters our blood through our lungs. The binding with other
proteins causes changes in the function of the affected organs such as the brain and the
cardiovascular system, and also the developing foetus. It can impair our concentration,
slow our reflexes, and make us confused and sleepy.
• Sulphur dioxide. SO2 (sulphur dioxide) in the air is caused due to the rise in combustion
of fossil fuels. It can oxidize and form sulphuric acid mist. SO2 in the air leads to diseases
of the lung and other lung disorders such as wheezing and shortness of breath. Long-
term effects are more difficult to ascertain as SO2 exposure is often combined with that
of SPM.
Health Impact of Specific Air Pollutants

27. Pollutant Description Sources Health Effects Welfare Effects
Carbon
Monoxide (CO)
Colourless, odourless gas
Motor vehicle exhaust, indoor
sources include kerosene or wood
burning stoves.
Headaches, reduced mental alertness,
heart attack, cardiovascular diseases,
impaired fetal development, death.
Contribute to the formation of
smog.
Sulfur Dioxide
(SO2) Colorless gas that dissolves in
water vapor to form acid, and
interact with other gases and
particles in the air.
Coal-fired power plants, petroleum
refineries, manufacture of sulfuric
acid and smelting of ores containing
sulphur.
Eye irritation, wheezing, chest
tightness, shortness of breath, lung
damage.
Contribute to the formation of
acid rain, visibility impairment,
plant and water damage,
aesthetic damage.
Nitrogen Dioxide
(NO2)
Reddish brown, highly reactive
gas.
Motor vehicles, electric utilities, and
other industrial, commercial, and
residential sources that burn fuels.
Susceptibility to respiratory infections,
irritation of the lung and respiratory
symptoms (e.g., cough, chest pain,
difficulty breathing).
Contribute to the formation of
smog, acid rain, water quality
deterioration, global warming,
and visibility impairment.
Ozone (O3)
Gaseous pollutant when it is
formed in the troposphere.
Vehicle exhaust and certain other
fumes. Formed from other air
pollutants in the presence of
sunlight.
Eye and throat irritation, coughing,
respiratory tract problems, asthma,
lung damage. Plant and ecosystem damage.
Lead (Pb)
Metallic element
Metal refineries, lead smelters,
battery manufacturers, iron and
steel producers.
Anemia, high blood pressure, brain and
kidney damage, neurological disorders,
cancer, lowered IQ.
Affects animals and plants,
affects aquatic ecosystems.
Particulate
Matter
(PM)
Very small particles of soot,
dust, or other matter,
including tiny droplets of
liquids.
Diesel engines, power plants,
industries, windblown dust, wood
stoves.
Eye irritation, asthma, bronchitis, lung
damage, cancer, heavy metal poisoning,
cardiovascular effects.
Visibility impairment,
atmospheric deposition,
aesthetic damage.

28. Industrial Smog
• Source: Pollution from the burning of coal and oil that contains sulfur
• Consists mainly of: Sulfur Dioxide, Sulfur Trioxide, soot and ash
(particulate matter) and sulfuric acid
• It can cause breathing difficulties in humans, plus acid rain damage to
plants, aquatic systems, and metal or stone objects
• London and Chicago have problems with industrial smog.
• Methods of reducing this smog: Alkaline Scrubbers reduce SO2 and
SO3 levels; electrostatic precipitators reduce particulates.

29. Photochemical Smog
• Source: Mainly automobile pollution
• Contains: Nitrogen Oxides, Ozone, Alkanals, Peroxyacyl
Nitrates (PANs), plus hundreds of other substances
• Effects: PANs cause eyes to water and can damage plants, O3
irritates eyes and deteriorates rubber and plants, NOx causes
acid rain.
• First observed in LA in the 1940s, Manila and Mexico City also
experience this kind of smog
• Catalytic Converters change NO to N2, Lean burning engines
reduce Nox, but create more CO and Hydrocarbons.

30. Control of Air
Pollution

31. Control of Air
Pollution

32. Control
of Air
Pollution
Gravity Settling Chambers:
These are long chambers where heavier and larger particles of
about 50 µm of slow-moving gaseous stream are deposited.

33. Control
of Air
Pollution
Bag or porous filters:
These are large sized porous bags of polyester, polyamide or Teflon
through which dry exhaust emissions are passed under pressure to filter
out particulate matter.

34. Control
of Air
Pollution
Cyclone Collectors:
Air stream with suspended particulate matter is whorled round in special
chambers. The particulate matter gets centrifuged and is periodically
removed from bottom of the chamber.

35. Control of Air
Pollution
Electrostatic Precipitators:
In these devices, air stream with particulate
matter is passed through regions having
electrically charged plates or electrodes. As
suspended particles are also charged, they
tend to aggregate near oppositely charged
electrodes or plates and become neutralized.
The particles are collected and removed
periodically.

36. Control
of Air
Pollution
Wet Scrubbers:
They separate gases by passing air stream through a fine spray of water which
dissolves gases like Ammonia, Sulphur dioxide and Nitrogen oxides.

37. Criteria
Pollutants
• The revised National Ambient Air Quality Standards (CPCB 2009) are notified for 12 parameters –
PM10, PM2.5, NO2, SO2, CO, O3, NH3, Pb, Ni, As, Benzo(a)pyrene, and Benzene.
• Although AQI is usually based on criteria pollutants (i.e. PM10, PM2.5, SO2, NO2, CO and O3), a new
approach to AQI which considers as many pollutants from the list of notified pollutants as possible is
desirable

39. Air Quality Index