This ppt was taken for MBBS students class, Source mostly Park and online resources for updates

1. Environment
Topic- AIR
Dr. Mamta G
MBBS MD Com.Med. (JIPMER)
Asst. Prof. MMC

2. Outline of presentation
1. Air
2. Air Pollution
3. Ventilation
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3. AIR

4. 1. Life giving oxygen
2. Body cooling
3. Transmits stimuli of smell and hearing
4. Disease causation- by agents/ pollutants
Human beings need a continuous supply of 10-20 m3/day air
Functions of Air
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5. Composition of Air
N2= 78.1%
O2= 20.9%
Argon
Neon
Krypton
Xenon
Helium
Water vapour
Ammonia
Dust
Bacteria
Spores
Veg.debris
CO2= 0.03%
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6. What makes air impure?
1. Respiration of human beings & animals
2. Combustion of coal, gas, oil, etc.
3. Decomposition of organic matter
4. Trade, traffic and manufacturing processes-dust, fumes, vapors and gases
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7. Self-cleansing mechanisms
1. Wind: sweeps away the impurities by its movement
2. Sunlight: oxidizing & killing bacteria
3. Rain: cleanses the atmosphere by removing the
suspended & gaseous impurities
4. Plant life: utilize CO2 & generate oxygen
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8. Air changes of occupied room
• Chemical changes: CO2 O2
• Physical changes
1. Rise in temperature
2. Increase of humidity
3. Decrease in air movement
4. Body odours
5. Bacterial pollution
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Comfort, health and
efficiency
• Feeling of suffocation/
discomfort
• Headache, drowsiness
• Inability to concentrate
• Risk of droplet infection
Resistance to disease

9. Discomfort
1. Subjective feeling or sensation in ill ventilated and over-crowded place
2. Leads to heat retention
3. Problems of ventilation are physical not chemical, cutaneous not respiratory
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10. Comfort
1. Complex subjective experience, depends on physical, physiological, and
psychological factors, difficult to determine
2. Comfortable thermal conditions --“a person can maintain normal balance in
production & loss of heat at normal body temperature & without sweating”
3. It’s the range of effective temperatures over which the majority of adults feel
comfortable
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11. Indices of thermal comfort
1. Air temperature
2. Air temperature + Humidity
3. Cooling power-Air temp.+ Humidity+ Air movement
(measured by Kata thermometer, devised by Hill)
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12. 4. Effective temperature-combines temp.,
humidity & movement of internal air (obtained by
special charts)
5. Corrected effective temperature (CET)-
includes radiant heat along Effective temperature
& also uses Globe thermometer
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Indices of thermal comfort

13. McArdle’s maximum allowable sweat rate- P4SR
Predicted four-hour sweat rate can be obtained from any combination
of dry and wet bulb temperature of the air, mean radiant air
temperature and air velocity, under different work intensity
• Comfort zone: 1-3 litre
• Just tolerable: 3-4.5 litre
• Intolerable: 4.5+ litre
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14. 14

15. Air pollution
The presence of substances (gases &
particulate matter) generated by the
activity of man in concentrations that
interfere with human health, safety or
comfort
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16. Sources of air pollution
1. Automobile
2. Industries
3. Domestic
4. Miscellaneous
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17. Automobiles
• Major source of air pollution through out urban areas, they include
1. Carbon monoxide
2. Lead
3. Nitrogen oxides
4. Particulate matter
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18. Industries
1. Heat generation in industries produces
smoke, sulphur dioxide, nitrogen
oxides and fly ash
2. Petrochemical industries generate
hydrogen fluoride, hydrochloric acid &
organic halides
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19. Domestic
• Domestic combustion of coal, wood
or oil is a major source of smoke,
dust, SO2, N02
• The most direct & important source
of air pollution affecting the health
of many people is tobacco smoke
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20. Miscellaneous
• Burning refuse
• Incinerators
• Pesticide spraying
• Natural sources (wind borne
dust, fungi, molds, bacteria)
• Nuclear plants
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21. 21
Delhi’s air pollution
emergency
November 2017

22. Major Pollutants Sources Adverse effects
1 Carbon monoxide Automobile exhaust, industries, incineration Headache, chest pain, impaired reaction time
2 Sulphur dioxide Power plants, smelters, oil refineries Asthma & COPD, resp. tract irritation
3 Lead Automobile exhaust Neuropsychological development
4 Carbon dioxide Coal/oil/gas combustion Global warming, climate change
5 Hydrocarbons Automobile exhaust, cigarette, incineration Lung cancer
6 Cadmium Steel industry, incineration, cigarette Impaired calcium metabolism, renal stones
7 Hydrogen sulphide Water treatment plants, oil refining, tanning Odour, neurological symptoms
8 Ozone Automobile exhaust (sec. product of reactions) Cough, resp. tract irritation, smog
9 Oxides of nitrogen Automobile exhaust, gas stoves, wood stoves Resp. tract irritation, bronchial hyperactivity
10 Polycyclic Aromatic
Hydrocarbons (PAH)
Automobile exhaust, industries,
Coal/oil/gas combustion, cigarette
Lung cancer, reproductive toxin
11 Particulate matter Automobile exhaust, industries, incineration COPD, Lung cancer, ARI 22

23. 23

24. Monitoring of air pollution
Indicators of air pollution
1. Sulphur dioxide
2. Smoke or soiling index
3. Grit & dust measurement
4. Coefficient of haze
5. Suspended particulate matter (SPM)
6. Air pollution index
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25. Effects of air pollution
Health aspects:
1. respiratory and cardio respiratory systems
2. the elderly, children, smokers & those with chronic respiratory difficulties
are most vulnerable
Social aspects:
1. destruction of plant & animal life
2. corrosion of metals
3. damage to buildings
4. cost of cleaning & maintenance & repairs
5. soiling of clothing
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26. Air pollution monitoring-India
• Central pollution control board sponsors “the national air quality
monitoring programme” in India
• database generated over last 14 years in 10 major Indian cities
• evaluation of long-term air quality trends for health related criteria
pollutants
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27. • Suspended particulate matter
exceeds the CPCB standards
in all cities
• Respirable suspended
particulate matter is higher at
industrial areas
• Acid rain in urban areas of
India
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28. National Air Quality Index
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29. 30

30. SAMEER APP LIVE MONITORING
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31. AQI Public display boards AQI of cities online 32

32. Prevention & control
1. Containment
2. Replacement
3. Dilution
4. Legislation
5. International action
6. Disinfection
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33. Containment
• Prevention of escape of toxic substances
into ambient air by a variety of
engineering measures such as
1. Enclosure
2. Ventilation
3. Air cleaning
4. Arresters
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34. Replacement
• Replacing a technological process
causing air pollution by a new process
1. Use of electricity, natural gas & central heating in place of coal
2. Reduce lead in petrol which is cumulative poison
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35. Dilution
1. Vegetation
2. Establishment of green belts
between industrial &
residential areas
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36. Legislation
To decrease the nuisance of air pollution,
the Govt. of India have enacted
“The Air (Prevention and Control of Pollution) Act” in 1981
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37. International action
• By WHO -international network of laboratories for
monitoring, study and issuing warnings of air pollution
1. two international centers at London & Washington
2. three centres at Moscow, Nagpur & Tokyo
3. 20 laboratories in various parts
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38. Disinfection of air
• It is still in the experimental stage and the methods employed are
1. Mechanical ventilation
2. Ultraviolet radiation
3. Chemical mists
4. Dust control
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39. Ventilation
40

40. Introduction
• replacement of vitiated air by a supply of fresh outdoor air
• control of quality of incoming air with regard to its temperature,
humidity & purity
• To provide a thermal environment that is comfortable & free from
risk of infection
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41. Standards of ventilation
• Adequate or inadequate
a. 1/5th of floor space- Windows
b. 2/5th of floor space- Doors + windows
• The fixing of standards is difficult and is based to a large extent on the efficiency
of ventilation in removing body odour
a. Cubic space: 300-3000 c.ft
b. Air change: 2-3 changes in living room & 4-6 changes in work room or
assemblies
c. Floor space: more important than cubic space & optimum requirement per
person vary from 50-100 sft. 42

42. Types of ventilation
• Natural ventilation
• Mechanical ventilation
1. Exhaust ventilation
2. Plenum ventilation
3. Balanced ventilation
4. Air conditioning 43

43. Natural ventilation
• Reliance is placed on certain forces which operate in nature
1. The wind: perflation, aspiration, cross ventilation
2. Diffusion
3. Inequality of temperature
#chief draw back – cant regulate the velocity
of the incoming air nor to adjust its
temperature or humidity

44. Exhaust ventilation
• Air is extracted or exhausted to the outside by exhaust fans
• Exhausting of air creates vacuum
• Used in -
1. Large halls and auditoriums
2. Industries to remove contaminants at their source
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45. Plenum ventilation
• fresh air is blown into the room by centrifugal fans to create a positive
pressure and displace the vitiated air
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46. Balanced ventilation
• This is a combination of the exhaust and plenum systems of ventilation
• The blowing fan must balance the exhaust fan
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47. Air conditioning
• simultaneous control factors affecting
both the physical and chemical conditions
of the atmosphere within any confined
space or room
• include temperature, humidity, air movement, distribution,
dust, bacteria, odours & toxic gases 48

48. 49