The document discusses air pollution and the Earth's atmosphere. It begins by describing the major regions of the atmosphere - the troposphere, stratosphere, mesosphere, and thermosphere. Most weather occurs in the troposphere, where air pollutants are also found. It then discusses what air is made of and defines air pollution. The major sources of air pollution are described as urban/industrial sources like power plants, transportation, construction, etc. and natural sources like dust storms, forest fires, and decaying organic matter. The effects of air pollution on human health, plants, the economy and atmosphere are outlined. Tips for reducing air pollution and the Air Quality Index are also summarized.

1. Air Pollution

3. The Earth’s Atmosphere

4. Major Region of the Atmosphere
Troposphere
• Nearest to earth, 11 miles thick at the equator, 5 miles thick at the poles.
• The rate of temperature drop is about 6.4 degree/1000 meters
• Tropopause
• Very cold layer at the top of troposphere is known as tropopause.
Stratosphere
• This zone starts at the top of the troposphere. It is 31 miles long. It is characterized by a rising temperature as the
altitude increases. Temp peaks up to the upper limit of the stratosphere because of the presence of ozone layer.
Mesosphere
• Extends roughly to 50 miles and its temp drops to between -80 and -90 degree celsius at the mesopause, a thin zone
where the temp stabilizes and soon starts to rise again the thermosphere is ascended.
Thermosphere
• Temp is very high in this region.

5. Importance of
Troposphere
• Most of the weather is formed in the
troposphere.
• Almost all the air pollutants emitted from
near surface sources are transported,
dispersed, transformed and removed on
this part of the lower atmosphere.

6. What is Air?
• The Earth’s atmosphere is a mixture of
gases that we call air.
• The gases that make up the atmosphere
exist as molecules.
• Of the three principal repositories for
pollutants in the environment-the
atmosphere, the oceans and the land-the
atmosphere is the most susceptible to
degradation.

7. Composition of
Air
Constant gases
• Nitrogen-78.08%
• Oxygen-20.95
• Argon, Ne, He, Kr, Xe
Variable gases
• Water vapour (4%), CO2, CH4,
Hydrogen, Nitrous Oxide, CO, Ozone,
Flurocarbon

8. What is Air Pollution?
• Air pollution is an atmospheric condition in
which substances are present at
concentrations higher than their normal
ambient levels to affect humans, animals,
vegetation, or materials significantly.
• Air pollution is the excessive concentration
of foreign materials in the air which
adversely affects the well-being of the
individual and causes damage to property
(American Medical Association)

9. Sources
of Air
Pollution
1. Urban and Industrial sources
A) Power generation
• Conventional fossil fuel power plants are the major
source of air pollution. Vast quantities of PM
including fly ash (SiO2), iron and aluminum oxides
from coal, and heavy metals from oil are emitted
from power plant stacks.
• Major pollutants are CO, CO2, SO2, NOx, HC and VOC.

10. 1. Urban and Industrial sources
B) Industrial Facilities
• These include mining, refining, manufacturing, smelting, pulp and
paper, chemical, metallurgical, pharmaceutical and other
industries that emit a wide variety of gaseous and particulate
matter in the atmosphere.
• Industrial air pollution comes from manufacturing products from
raw materials, such as iron from ore, gasoline from crude oil etc.

11. 1. Urban and Industrial sources
C) Transportation
• Includes automobiles, buses, trucks, airplanes,
boats etc. which are all mobile sources.
• Major pollutants come from transportation
sources are CO, CO2, NO, SO2, HC and VOCs.

12. 1. Urban and Industrial sources
D) Process Emissions
• These include furnaces and other processes used for heating
homes, office, commercial buildings, fireplaces, stoves, backyard
barbecue grills (Polycylic aromatic hydrocarbons [PAHs] ) and
open burning of refuse and leaves.
• The major pollutants emitted to the atmosphere are CO, CO2, NO,
SO2, HC, VOC and PM.

13. 1. Urban and Industrial sources
E) Construction Activities
• These include land clearing, demolition,
digging, grinding, pulverization, paving,
painting and other construction related
activities. Pollutants emitted to the
atmosphere are dust and other PM, HC,
VOC and so on.

14. 2. Agricultural and other Rural Sources
a) Dust Blowing
• Ploughing, tilling and harvesting lead to
considerable amounts of dust blowing in the wind.
b) Slash Burning
• Land clearing by burning of forests, straw, wild
grass, and agricultural waste products constitute a
major source of smoke and haze in the
countryside.

15. 2. Agricultural and other Rural Sources
C) Soil Emissions: cropland are usually treated with heavy applications of
fertilizers containing nitrates and phosphates. Treated soils emit
Nitrogen Oxides that are produced by microbial activity in the topmost
soil layer.
D) Pesticides: Applications of pesticides to croplands through spraying by
aircraft may result in their transport to residential areas.
E) Decaying wastes: Release ammonia, methane and noxious vapors to
the atmosphere. Large cattle and hog farms constitute major sources
of air pollution.

16. 3. Natural Sources
A) Wind erosion: Wind erosion of bare soils and desert
lands by strong winds or by dusts devils can result in
major dust storms. Dust particles consist mainly SiO2.
Also, may contain traces of heavy metals.
B) Forest Fires: emit large amounts of smoke, CO, CO2,
NOx and HC.

17. 3. Natural Sources
C) Sea Spray: by wave breaking in strong winds is the
major source of salt particles in the atmosphere.
D) Soil microbial process: These include aerobic and
anaerobic respiration of natural soils and vegetation
resulting the emissions of nitric oxide, methane,
hydrogen sufide and ammonia to the atmosphere.

18. 3. Natural Sources
E) Natural decay of organic matter: these include the
decay of vegetation and other organic matter, which
emits mainly methane, hydrogen sulfide and
ammonia.
F) Lightning: A large amount of nitric oxide is
produced during lightning which may then participate
in photochemical reactions creating ozone.

19. Air Pollution sources in an urban setup
Small sources such as boilers, generators, light industries.
Point sources such as major industrial sites
Mobile sources such as on-road motor vehicles, train, steamers, air crafts,
Area sources such as waste deposits and places where open burning of waste materials from
agriculture, forestry and land clearance occur
Local biogenic and natural sources such as deserts and eroded areas
Transboundary air pollution from distance sources comprising emissions from fixed, mobile
and other sources.

20. Air Pollution Types
• Primary pollutants: emitted directly from
sources without undergoing any chemical or
physical transformation.
• Secondary Pollutants: formed in the
atmosphere due to chemical reactions
among primary pollutants and normally
present atmospheric constituents.

21. Gaseous Pollutants
Sulfur Compounds
• Primary Pollutants: SO2, SO3, H2S
• Secondary Pollutants: H2SO3, sulphate
ions, NH4SO4
Nitrogen Compounds
• Primary Pollutants: NO, N2O, NO2, NH3
• Secondary pollutants: HNO3, nitrate, and
ammonium ion.

22. Inorganic Carbon Compounds
• Primary pollutants: CO, CO2
Organic Carbon Compounds
• Primary pollutants: CH4,
terpenes, isoprene
• Secondary pollutants: organic
nitrates, peroxides

23. Principal
pollutants
and sources
of air
pollution

24. Effects of
Air
Pollution

25. Effects on
Human
Health
• The prime factors
affecting human health
are:
• Nature of pollutants
• Concentration of
pollutants
• Duration of exposure
• State of the health of
the receptor
• Age group of the
receptor
• Eye irritation
• Nose and throat
irritation
• Irritation of the
respiratory tract
• Increase in mortality
and morbidity rate
• Fine Particles can travel
up to the placenta of an
unborn baby

26. Health
Effects
• Increases the risk of premature birth and low birth weight
• Can permanently damage the brain of the babies in the womb
• Asthmatic attacks
• Chronic pulmonary diseases like bronchitis and asthma are
aggravated by a high concentration of SO2, NO2, PM, and
photochemical smog.
• Cardiac diseases
• Additional stress on patients suffering from cardiovascular
and pulmonary diseases
• Cancer
• IQ Reduction

27. Effects on plants
• SO2: necrosis in interveinal areas and skeletonized
leaves
• Ozone: premature aging and suppressed growth, the
collapse of leaves, necrosis, and bleaching
• Fluorides: necrosis at leaf tip.
• Nitrogen dioxide: suppressed growth, leaf bleaching
• Ethylene: leaf abscission

28. Effects on Economy
Air pollution damage to property covers
a wide range: corrosion of metals,
soiling and eroding of building
surfaces, fading of dyed materials,
rubber cracking, spoiling or destruction
of vegetation, effects on animals, and
interference with production and
services.

29. Effects on Atmosphere
Visibility Reduction
➢Reduction in visibility caused by the absorption and scattering of light
by airborne particles.
➢Widespread regional hazes are often caused by air pollution dispersed
over large regions.
➢Natural aerosols and the associated fogs, rain, snow, windblown dust,
and natural hazes can reduce the visibility to a few tens of meters.

30. Tips for clean air
• Walk or ride a bike
• Shop by phone or mail
• Ride public transit
• Telecommute
• Accelerate vehicle speed gradually
• Keep your car tuned
• Replace car air filter
• Keep tires properly inflated
• Drive new car
• Select products that have low amounts
of VOCs
• Look for paints labeled zero VOCs
• Paint with a brush, not a sprayer
• Store solvents in airtight containers
• Turn off light when you leave room
• Use energy saving fluorescent bulbs
• Use fan instead of air conditioning

31. Tips for clean air
• Use a programmable thermostat that
automatically turns off the AC
• Insulate your water heater
• Avoid rigorous physical activities on days with
unhealthy air
• Drive slowly on unpaved roads
• Choose recycled products
• Reuse paper bags
• Limit dry cleaning
• Reduce consumption of electricity

32. Air Quality Index (AQI)
A way of transforming complex air quality measurements
into a single number or descriptive term.
Describes both the measured air quality and the publicly
perceived air quality at any given time.
An index for reporting daily air quality.
Tells how clean or polluted air is.
Expresses what associated health concerns should be
aware of.
Focuses on health effects that can happen within a few
hours or days after breathing polluted air.

33. Air Quality
Index for
Bangladesh

34. Thank You