Covers broad range of topics from environment for MBBS students class. Source- Park

1. Environment
Housing, Noise, Light, Radiation & Meteorological Factors
Dr. Mamta G
MBBS MD Com.Med. (JIPMER)
Asst. Prof. MMC

2. Outline
1. Housing
2. Light
3. Noise
4. Radiation
5. Meteorological environment

3. Housing

4. Introduction
• Not mere physical structure-providing shelter, but also the
immediate surroundings, and the related community
services and facilities

5. Goals of housing
1. Shelter: sanitary shelter (basic need)
2. Family life: adequate place for family activities
3. Access to community facilities: health, school, shopping,
place of worship etc.,
4. Family participation in community life: offers help in times
of need
5. Economic stability & well being of the family

6. Criteria for healthful housing
• Physical protection
• Prevent spread of communicable diseases
• Protection from hazards of exposure to noise & pollution

7. Housing Standards

8. Site
• Elevated from surrounding
• Independent access to a street of adequate width
• Away from breeding places of insects
• Away from nuisances such as dust, smoke, smell excessive noise & traffic
• Soil should be dry & safe for foundation

9. Set back
• Open space all around house
• For proper lighting & ventilation
• In rural area recommended built up area
should not be more than one-third
• In urban area it may be allowed up to two-thirds

10. Floor
• Impermeable: easily washed & kept clean and dry.
Mud floor break up & cause dust
• Smooth and free from cracks & crevices to prevent
breeding of insects
• Damp-proof
• Height of plinth should be 2-3ft

11. Walls
• Reasonably strong
• Low heat capacity
• Weather resistant
• Unsuitable for harborage of rats & vermin
• Not easily damaged
• Smooth
These standards can be attained by 9-inch brick wall plastered smooth
& coloured cream or white

12. Roof
• Height should not be less than 10 feet in the absence of
air conditioning for comfort
• Should have a low heat transmittance coefficient

13. Rooms
• The no. of living rooms should not be less than two, at least one of
which can be closed for security
• The number & area of rooms should be increased according to size
of family

14. Floor area
• Living room floor area should be at least 120 sq.ft for occupancy by more
than one person & at least 100 sq.ft for single person
Cubic space
• Unless mechanical replacement of air is provided the height of the room
should be such as to give an air space of at least 500 cu.ft per capita ,
preferably 1000 cu.ft

15. Windows
• Unless mechanical ventilation and artificial lighting is provided, every
living room is provided with at least 2 windows
• Placed at a height of more than 3 feet above the ground in living
room
• Window area should be 1/5th of floor area
• Doors & windows combined should have 2/5th the floor area

16. Lighting
• The day light factor should exceed 1% over half the floor area
• It is the ratio of illumination at a given point exposed simultaneously to
the whole hemisphere of the sky (taken as 500 foot candles) excluding
direct sunlight

17. Kitchen
• Every dwelling house must have a separate kitchen
• Adequately lighted
• Arrangement for storing for food, fuel & provisions should be made
• Water supply with a sink to wash utensils
• Floor should be impervious

18. Privy
• A sanitary privy is a must for every family belonging exclusively to it
& readily accessible
Garbage & refuse
• These should be removed from the dwelling daily and disposed
of in a sanitary manner
Bathing & washing
• The house should have a safe and adequate water supply
available at all times

19. Rural housing
• Lower standards
• Minimum two living rooms
• Ample verandah space
• Separate kitchen
• A sanitary latrine
• Sanitary well or tube well within 1/4th mile
• Cattle shed should be 25 ft. away & open all sides
• Adequate arrangement for disposal of waste water
refuse and garbage

20. Housing & health
1. Respiratory infections: common cold, tuberculosis, diphthria, bronchitis,
measles, pertussis etc.
2. Skin infections: scabies, ringworm, impetigo, leprosy.
3. Rat infections: plague
4. Arthropods: houseflies, mosquitoes, fleas and bugs
5. Accidents
6. High Morbidity & mortality
7. Psycho social effects: sense of isolation, neurosis and behavior disorders

21. Overcrowding
• More people are living within a single dwelling than there is space for, so that –
• movement is restricted
• privacy secluded
• hygiene impossible
• rest & sleep difficult
• Overcrowding is a health problem in human dwellings. It may promote the
spread of respiratory infections

22. (1) Persons per room
• 1 room - 2 persons
• 2 rooms - 3 persons
• 3 rooms - 5 persons
• 4 rooms - 7 persons
• 5 or more - 10 persons (additional 2 for each further room)

23. (2) Floor space
• 110 sq.ft or more : 2 persons
• 90-100 sq.ft : 1½ persons
• 70-90 sq.ft : 1 person
• 50-70 sq.ft : ½ person (a baby under 12 months= 0 unit;
1-10 yr. counted as 1/2 unit)
• Under 50 sq.ft : nil

24. (3) Sex separation
if 2 persons over 9 yrs of age, not husband & wife, of opposite sexes are
obliged to sleep in the same room

25. Indicators of housing
• Indicators use has become widespread for the measurement of
quality of life
• They are
• Physical indicators
• Economic indicators
• Social indicators

26. Physical indicators
Based on :
• Floor space
• Cubic space
• Room height
• Persons per room
• Rooms per dwelling
• Environmental quality

27. Economic indicators
• Cost of the building
• Rental levels
• Taxes
• Expenditure on housing

28. Social indicators

29. Related to prevent illness
• Frequency of illness due to inadequate sewage & garbage collection
• Frequency of illness asso. with contaminated water source
• Frequency of insect borne diseases
• Frequency of illness due to overcrowding
• Frequency of illness due to accidents
• Frequency of illness due to proximity to animals
• Access to medical facility

30. Indicators related to comfort
• Thermal comfort
• Acoustic comfort
• Visual comfort
• Spatial comfort

31. Indicators related to mental health
• Frequency of suicides in the neighbourhood
• Neglected & abandoned youth in the neighbourhood
• Drug abuse (including alcohol) in the neighbourhood

32. Public policy
• Approach is indicated in 5 year plans
• Separate ministry of works & housing was created in 1952
• Govt.housing programme:
• i) public sector (for Govt.employees)
• ii) social housing schemes (for low & middle income groups)
• Housing boards are established to promote housing activities

33. Housing site & construction assistance
• Provision of free house sites
• Construction assistance with varying proportion of subsidy and loan
• Indira Awas yojana
• PM Awas Yojana

34. Light

35. Introduction
• Good lighting is essential for vision
• Poor lighting puts visual apparatus to strain
• May lead to general fatigue & loss of efficiency

36. Light factors
1. Sufficiency: differentiates details of object
2. Distribution: uniform & same intensity
3. Absence of glare: excessive contrast
4. Absence of sharp shadows: confuse & strain
5. Steadiness: flickering causes strain to eye
6. Colour of light: natural light is soothing
7. Surroundings: contrast, reflection

37. Measurement of light
• Luminous intensity : power of a light source
measured as candelas
• Luminous flux : flow of light (lumen)
• Illumination : amount of light
reaching surface in lux
• Brightness : amount of light reflected
from surface (lamberts)

38. Natural lighting
• Orientation: north or south for uniform illumination
• Removal of obstructions
• Windows: a tall window gives greater penetration of light & a broad
window gives greater diffusion of light
• Interior of the room: ceiling-white; upper portion of wall-light tinted;
lower portion of wall-dark so as to give comfortable contrast to eyes

39. Day light measurement
• Day light factor: It is the ratio of illumination at a given
point to illumination at a point exposed simultaneously to
the whole hemisphere of the sky excluding direct sunlight

40. Methods of artificial lighting
• Filament lamps : 5% light; 95% heat
• Fluorescent lamps : 21% light; 79% heat

41. Filament lamps
• Widely used
• Electric current heats up the tungsten
filament
• Accumulation of dust on the bulbs
reduces illumination by 30-40%, hence
needs cleaning frequently

42. Fluorescent lamps
• Economical in use
• Cool and efficient
• Simulates natural light
• Glass tube filled with mercury vapour and an electrode at each end
• Inside tube is coated with fluorescent chemicals, which absorb practically
all the UV radiation & remit radiation in all visible range

43. Lighting standards
• Visual task : Illumination(lux)
• Casual reading : 100
• General office work : 400
• Fine assembly : 900
• Very severe tasks : 1300-2000
• Watch making : 2000-3000

44. Biologic effects
• Day light could cause the in vitro
degradation of bilirubin (used as
therapeutic procedure)
• Biologic rhythms of body temperature
• Physical activity
• Stimulation of melanin synthesis
• Activation of precursors of vitamin D
• Adrenocortical secretion
• Food consumption

45. Noise

46. Definition
• Unwanted sound
• Wrong sound, in the wrong place, at the wrong time
• 20th century is described as the “century of Noise”
• Noise pollution is the recently coined to signify the vast
cacophony of sounds that are produced in modern life
leading to health hazards

47. Properties of noise
• Loudness or intensity
• Frequency

48. Loudness
• Depends upon the amplitude of the vibrations which initiated the noise
• It is measured in decibels
• Daily exposure up to 85 db is about the limit people can tolerate
without substantial damage to their hearing

49. Community noise levels
• Whispering : 20-30 db
• Quiet library : 40-50 db
• Normal conversation : 60-70 db
• Heavy street traffic : 70-80 db
• Printing press : 90-100 db
• Train passing station : 100-110 db
• Motor car horn : 120-130 db
• Threshold of pain : 140-150 db
• Mechanical damage : 150-160 db

50. Acceptable noise levels
• Residential: Bed room(25); Living(40)db
• Commercial: Office (35-45)
Conference (40-45)
Restaurants (40-60)
• Industrial: Work shop (40-60); Laboratory (40-50)
• Educational: Class room (30-40);
• Hospitals: Wards (20-35)

51. Frequency
• It is denoted as Hertz (Hz)
• One Hz is equal to one wave per second
• Human ear can hear frequencies from about 20-20000 Hz
• This range is reduced with age
• The range below 20 Hz are infra audible
• The range above 20000 Hz is ultra sonic

52. Effects of noise exposure
• Auditory effects
• Auditory fatigue
• Deafness
• Non-auditory effects
• Interference with speech
• Annoyance
• Efficiency
• Physiological changes

53. Control of noise
• Careful planning of cities (zones)
• Control of vehicles
• To improve acoustic insulation of building
• Industries & railways (protective green belts)
• Protection of exposed persons (periodic check-
up)
• Legislation (compensation)
• Education (through all available media)

54. Radiation

55. Sources of radiation
• Natural (average person is exposed to 0.1 rad/yr)
• Cosmic rays
• Environmental
• Terrestrial radiation
• Atmospheric radiation
• Internal radiation
• Man-made
• X-rays
• Miscellaneous

56. Cosmic rays
• Originate in outer space
• At ordinary living altitude their impact is about 35 mrad a year
• At altitude above 20 km it is very high
• A jet pilot receives about 300 mrad/year

57. Environmental
• Terrestrial: Radio active elements &
isotopes present in man’s
environment. Eg. Soil, rock etc.,
• Atmospheric: the external radiation
from the radioactive gases. It is
about 2 mrad/yr
• Internal: from radioactive matter
stored in the body tissues, about 25
to as high as 80 mrad/yr

58. Man-made sources
• X-rays: patients group/radiologists &
technicians (exposure to single x-ray film
varies roughly from 0.02 rad to 3 rad)
• Miscellaneous: every day appliances (TV
sets, luminous wrist watches is too small
to be important)

59. Types of radiation
• Ionizing radiation (able to penetrate tissues)
• Electromagnetic radiation (x-ray & gamma ray)
• Corpuscular radiation (electrons & protons)
• Non-ionizing radiation (wavelengths longer than those of ionizing
radiation & includes UV radiation, visible light, infrared radiation,
microwave radiation & frequency radiation)

60. Radiation units
• Roentgen: it is unit of exposure the amount of radiation absorbed in air
at a given point i.e., no. of ions produced in 1ml
• Rad: it is the unit of absorbed dose, the amount of radioactive energy
absorbed per gram of tissue or any material
• Rem: it is the product of the absorbed dose and the modifying factors

61. Biological effects of radiation
• Somatic
• Immediate
• Radiation sickness
• Acute radiation syndrome
• Delayed
• Leukemia
• Carcinogenesis
• Fetal developmental
abnormalities
• Shortening of life
• Genetic
• Chromosome mutations
• Point mutations

62. Radiation protection
• The amount of radiation received from
outer space is estimated to be 0.1 rad a
year
• Additional permissible dose should not
exceed 5 rad a year
• Effective protective measures include
proper use of lead shields & lead aprons
• Workers must wear a film badge or
dosimeter, beside periodic
examinations, regular working hours,
recreation & holidays

63. Meteorological
environment

64. Elements of Meteorological environment
1. Atmospheric pressure
2. Air temperature
3. Humidity
4. Rainfall
5. Direction & speed of wind
6. Movements of clouds & character of weather

65. Atmospheric pressure
• Man is physiologically adapted to live at 760 mm of Hg pressure or close to it
• The atmospheric pressure falls as altitude increases & rises as altitude
decreases

66. Measurement of atm. pressure
• Fortin’s Barometer
• Kew Pattern Station Barometer
(widely used by the Indian met.
Department)
• Barograph (useful for obtaining a
continuous record of atmospheric
pressure)

67. Effects of high altitude

68. Acute mountain sickness
• It is a common and transient condition
characterized by headache, insomnia,
breathlessness, nausea, vomiting &
impaired vision (hypoxia/intricate
biochemical & hormonal disturbances in
body)

69. High altitude pulmonary edema
Appears on about 3rd day at high altitude
As pulmonary edema develops the pt. develops a cough, irregular or cheyne-
stokes breathing, oligurea, mental confusion & hallucinations, stupor, seizures
and coma (army medical officers)

70. • Caisson disease: excess conc. of Nitrogen exerts a
narcotic action leading to loss of mental functions
and consciousness and along with excess CO2 &
Oxygen can lead to convulsions and death.
• When the person comes up to the surface, the
gases dissolved under pressure are released and
cause air embolism, the effects of which are fatal
Effects on health-low altitude

71. Air temperature
• The factors which influence the temperature are latitude of the
place, altitude, direction of wind and proximity to the sea

72. Measurement
• Dry bulb thermometer
• Wet bulb thermometer
• Maximum thermometer
• Minimum thermometer (spirit)
• Six’s maximum & minimum thermometer
• Globe thermometer (radiant heat)
• Wet globe thermometer (env. heat)
• Silvered thermometer (accurate reading)
• Kata thermometer (alcohol-for measuring cooling power
of air)

73. Heat stress indices
Heat stress is the burden of heat that must be dissipated if the body is
to remain in thermal equilibrium. The factors which influence are
metabolic rate, air temp.& movement, humidity,
• Equatorial comfort index
• Heat stress index
• Predicted four hour sweat rate

74. Effects of heat stress

75. Heat stroke
• Failure of heat regulating mechanism
• High body temp.-110° F/43.3° C
• Delirium, convulsions & partial or
complete loss of consciousness
• Skin is dry and hot
• Sweating is absent
• Outcome is fatal

76. Heat stroke-management
• Rapid cooling of body in ice water bath till the rectal temperature falls
below 102° F
• Monitoring of rectal temp. to prevent significant hypothermia
• Hypovolaemia, hyperkalaemia, rhabdomyolysis, hypocalcaemia &
bleeding diathesis may require intense supportive treatment
• Patient should be kept in bed for several days till the temp.control
becomes stable

77. Heat hyperpyrexia
• Impaired functioning of the heat-
regulating mechanism but without
characteristic features of heat
stroke
• Temp.106° F
• May proceed to heat stroke

78. Heat exhaustion
• Milder illness than heat stroke
• Caused primarily by the
imbalance or inadequate
replacement of water and salts
lost in perspiration due to
thermal stress
• Occurs after several days of
high temp.
• Body temp. normal & may not
exceed 102° F
• Symptoms are dizziness,
weakness & fatigue
• Treatment is fluid & electrolyte
balance

79. Heat cramps
• Occurs in persons doing heavy
muscular work in high temp. &
humidity
• These are painful & spasmodic
contractions of skeletal muscles
• The cause is due to loss of
sodium & chlorides in sweat

80. Heat syncope
• The person standing in heat becomes
pale, B.P falls & collapses suddenly
• It results from pooling of blood in lower
limbs due to dilatation of blood vessels
• Patient should be made to lie in the
shade with foot end raised. Recovery
comes within 5-10 minutes

81. Preventive measures
• Replacement of water-encouraged to drink cool
water (1 lit.per hour)
• Regulation of work-cut down time of exposure to
hot temp. & by periods of rest in between
• Clothing-worn should be light, loose & light
colours
• Protective devices-protective goggles, shields &
helmets are helpful
• Work environment-proper ventilation & A.C

82. Cold stress
• Cold injury (hypothermia): characterized by
numbness, loss of sensation, muscular
weakness, desire for sleep, coma & death
• Frost bite: local cold injury occur at temp.
above freezing due to formation of ice
crystals in between the cells of tissues.
Affected part should be warmed using water
at 44° C, and intake of hot fluids promotes
general rewarming

83. Global warming
• Emission of green-house gases
• Increase of about 3° C in the average
global surface temp. by 2030
• Rise in the sea level of 0.1-0.3m by
2050
• Occurrence of extreme climatic events
such as cyclones, heat waves &
draughts
• Many species may fail to adapt
• Lead to massive consequences