1) Air pollution is defined as the presence of substances in the atmosphere that interfere with human health or comfort. Major sources include automobiles, industries, domestic sources, and tobacco smoke. 2) Air pollutants can have both immediate and delayed health effects, including respiratory illnesses and increased risk of chronic diseases. They also have social and economic impacts. 3) Monitoring of air pollution involves measuring levels of pollutants like sulfur dioxide and particulate matter. Prevention and control methods include containment, replacement, dilution, legislation, and international cooperation.

1. AIR POLLUTION
Dr. Niraj Bharadva
Assistant Professor,
Community Medicine Dept

3. Learning Objectives
 Air
 Indices of Thermal Comfort
 Air Pollution-Definition
Sources
Effects
Prevention & control
 Disinfection of Air

4. AIR
• Immediate environment of man
• Functions of air and atmosphere
 Supply of oxygen which is life giving
 Cooling of the human body
 Functioning of special senses such as smell and
hearing by air-transmitted stimuli
• Requirement of air= 10-20m³ per day

5. Air is rendered impure by:-
1) Respiration of man and animals
2) Combustion of coal, gas, oil etc
3) Decomposition of organic matter
4) Trade, trafficking and manufacturing
processes which gives off dust, fumes, vapors
and gases

6. The air composition is kept constant by:
 Wind - Sweeps away the impurities by its
movement
 Sunlight and atmospheric temperature –
Oxidize impurities & kill bacteria
 Rain - washes the impurities away
 Plant life - green plants utilize the CO2 and
generate oxygen

7. Changes in occupied room
 Chemical
 Progressive
contamination by CO2
 ↓ in Oxygen content due
to metabolic processes
 CO2 at rest gives off =
0.7 cu.ft/ hr
 CO2 at Activity =
2 cu.ft/hr
 Physical
 Rise in temperature up
to 400 Btu
 ↑ of humidity
 ↓ air movement
 Body odours
 Bacterial pollution

8.  Unless the vitiated air is replaced by fresh air ,
it may adversely affect the comfort, health &
efficiency of the occupants
 Feeling of suffocation, headache, drowsiness,
and inability to concentrate
 Risk of droplet infection

9. DISCOMFORT
 Subjective sensation which people feel in ill-
ventilated rooms
 It was believed that it was due to CO↑ 2 and O↓ 2
 Studies have shown that the O2 and CO2can be ed↓
and ed respectively to 18% and 5% , without↑
any
adverse effects provided the temperature and
humidity are kept satisfactory
 e.g. Black Hole Experiment in Kolkata

10.  The discomfort is due to physical changes like
 Temperature
 Humidity
 Air-movement and
 Heat radiation
 which determine the cooling power of the air with
respect to human body.

11. Indices of thermal comfort
 Air Temperature
 Air Temperature + Humidity
 Air Temperature+ Humidity + Air Movement
(Cooling Power)
 Effective Temperature
 Corrected Effective Temperature

12. 1. AIR Temperature - Alone is not enough
2. Air Temperature + Humidity –
Also unsatisfactory
3. Air Temperature+ Humidity + Air Movement
(Cooling Power)
 Cooling power measured by Kata thermometer;
Dry Kata reading ≥6 & Wet Kata reading ≥ 20
are Indices of thermal comfort
 also not reliable

13. 4. Effective Temperature -
 Arbitrary index;
 Which combines in a single value the effect
of temp, humidity and movement of the
internal air on the sensation of warmth or
cold felt by the human body
 Obtained from special charts and scales

14. 5. Corrected Effective Temperature (CET) -
 4 FACTORS - Air temperature
Humidity
Velocity
Mean radiant heat
(Include effect of radiant heat)

15. 6. Mc Ardle’s Maximum Allowable Sweat Rate –
 4.5 L. of sweat in 4 hours is compatible with
physiological normal reaction of acclimatized
healthy young men for repeated exposures to
heat
 P4SR = Predicted 4 hour sweat rate
 P4SRvalue of 3=upper limit of comfort zone

16. COMFORT ZONES
 Def:- The range of CETs over which the majority of
adults feel comfortable
 There is no single zone of comfort
Sense of comfort CET˚C
Pleasant and cool 20
Comfortable and cool 20 -25
Comfortable 25 - 27
Hot & uncomfortable 27 – 28
Extremely hot 28 – 30
Intolerably hot 30 +

17. Zones P4SR (Litres)
Comfort zone 1 – 3
Just tolerable 3 – 4.5
Intolerable 4.5+

18. AIR POLLUTION
 It signifies the presence of substances such as
gases, mixture of gases and particulate matter
in the surrounding atmosphere,
 generated by the activities of man,
 in concentrations that interfere with human
health, safety or comfort, or injurious to
vegetation

19.  The direct effect of air pollutants on plants,
animals and soil can influence the structure
and function of ecosystems, including self
regulation ability, thereby affecting the quality
of life.
 It is one of the present day health problems
throughout the world

20. Sources of air pollution
 Automobiles
 Industries
 Domestic sources
 Tobacco smoke

21. Automobiles
Emit black smoke and fumes which contain
Hydrocarbons
Carbon monoxide
Lead
Nitrogen oxide & Particulate matter
Diesel engines when misused emits black
smoke

22. Lead
 Toxic
 Mental, nervous effects & behavioural
problems in children
 Elderly people, children and those with chronic
difficulties are most vulnerable
 ↑ in air pollution in morbidity & mortality→ ↑

23. Automobiles

24. Industries
 Combustion of fuel to generate heat
 Produce smoke, SO2, Nitrogen oxides & fly ash
 Petrochemical industries HF, HCL, organic→
halides
 Other industries discharge large amount of CO,
CO2, Ozone, H2S and SO2 into the atmosphere
 High chimneys high speed→

25. Industries

26. Industries

27. Domestic sources
 Domestic combustion of coal ,wood or oil is a
major source of smoke , dust, sulpher dioxide &
nitrogen dioxide
 The London disaster of 1952 - thousands died
due to domestic coal burning

28. Domestic sources

29. Tobacco smoke
 The most direct & important source of air
pollution affecting the health of many people is
tobacco smoke
 Passive smoking

30. Tobacco smoke

32. Miscellaneous
 Burning refuse
 Incinerators
 Pesticide spraying
 Wind-blown dust
 Fungi, molds and bacteria
 Nuclear energy programmes

33.  Pollutants and water vapour getting trapped at
the lower levels Threat to health→
 SMOG= combination of smoke and fog
 Air pollutants > 100 substances
 Important ones are
 CO, SO2, CO2, H2S, lead, hydrocarbons, cadmium,
ozone
 Polynuclear aromatic hydrocarbons(PAH)
 Particulate matter---organic& inorganic

34. SMOG

35. Indoor Air Pollution
 One of the four most critical global
environmental problems
 More people are exposed than outdoor pollution
 Rural people, women and children are more
affected than men
 Acute respiratory infections—Pneumonia
 Chronic lung disease
 Adverse pregnancy outcomes - stillbirth

36. Sources of indoor air pollution
 Tobacco smoke
 Stove
 Aerosol sprays
 Gas heaters
 Gas cookers, cigarettes
 Solvents, adhesives, resin products
 Electric arcing, UV light sources
 Building materials - asbestos
 Appliances

37. Health aspects
of Air Pollution
Immediate effects Delayed effects
Respiratory effects Chronic bronchitis
Acute bronchitis Lung cancer
Death by suffocation Bronchial asthma
Eye irritations,
congestions
Emphysema
Respiratory allergies

38. Social and economic aspects
of Air Pollution
o Destruction of plant and animal life
o Corrosion of metals
o Damage to buildings
o Cost of leaning , maintenance & repairs ↑
o Aesthetic nuisance
o ↓ visibility in towns
o Soiling and damage to clothing

39. Monitoring of air pollution
 SO2- major contaminant in many urban and
industrial areas
 Its concentration is estimated in all pollution
surveys
 Smoke or soiling index- a known volume of
air is filtered through a white filter paper &
stain is measured by photoelectric meter
 Expressed as mcg/m3
of air

40. Monitoring of air pollution
 Grit & dust measurement -
 Deposit gauges collect grit, dust & other solids ,
analyzes monthly
 Coefficient of Haze -
 Used in USA, Assess the amount of smoke or
other aerosol in air

41. Monitoring of air pollution
 Air pollution index
 Takes into account one or more pollutants as a
measure of severity of pollution
 E.g. 10 times SO2 + 2 times CO + 2 times the
Coefficient of Haze

42. Prevention and control
of air pollution
 Control of air pollution ---an engineering
problem
 WHO recommended the following procedures
a) Containment :
Prevention of escape of toxic substances into
the ambient air
Development of arrestors
Engineering methods : Enclosure, ventilation &
air cleaning

43. Prevention and control
of air pollution
b) Replacement :
 Replacing a pollution causing process by a non-
pollution process
 e.g. Removal of lead from petrol - unleaded
petrol

44. Prevention and control
of air pollution
c) Dilution :
 Green belts between industrial areas and
residential areas
d) Legislation :
 Height of chimneys
 Power to local authorities to carry out
investigations

45. Prevention and control
of air pollution
 Research and education concerning air
pollution
 Creation of smokeless zones
 Enforcement of standards for ambient air
quality
 Making pollution check-up of vehicles
compulsory

46. Prevention and control
of air pollution
 International action
 WHO established International Network of
Laboratories for the monitoring and study of
air pollution
 2 centers at London and Washington
 3 centers at Moscow, Nagpur (India) & Tokyo
 20 laboratories in various parts of the world

47. Disinfection of air
 Mechanical ventilation
 ↓ vitiated air and bacterial density
 Ultraviolet radiation
 In OTs and infectious disease wards
 Chemical mists
 Tri ethylene glycol vapors – effective air
bactericides
 Dust control
 Application of oil to floors of hospital wards ↓
bacterial content of the air

48. Thank You