AIR IS NEED OF BODY1. Air is essential for maintenance of life . Air supplies

oxygen to human body , which is essential for life . Clean air is necessary for our health and longevity . An average person breathes 30 lbs of air each day, which is about six times of his food and water intake . The oxygen in the air is utilised to produce energy in each cell of the body.

2. Air has two important function , i.e. exchange of gases during respiration and regulation of body temperature.

3. Respiration is the process of inspiration and expiration , air in the lungs loses 4 % of oxygen that is absorbed by the blood in the pulmonary capillaries , and gains carbonic acid from the venous blood to the extent of 3.5 to 4 %.

4. Feeling of suffocation or discomfort is experienced by

the occupants in an insufficiently ventilated room and

also complaints headache , drowsiness and inability to

concentrate.

5. Temperature , humidity , air movement and heat

radiation are the factors which determine the ‘cooling

power’ of the air with respect to the human body.

Indices of thermal

Thermal comfort is a complex entity . Much work was done in

the past to determine what constitute ‘thermal comfort’.

Several indices have been put forward from time to time to

express thermal comfort and heat stress . These are as

follow:-

1. Air temperature

2. Air temperature and humidity

3. Cooling power

4. Effective temperature

5. Corrected effective temperature

An instruments designed by hill called ‘Kata thermometer’ is

used to determine cooling power of air in a room.

COMFORT ZONES

Comfort is quite a complex subjective experience , which

depends not only on physical ,physiological factors but also on

psychological factors which are difficult to determine .

Considering only the environmental factors , comfortable

thermal conditions are defined as those under which a person

can maintain normal balance between production and loss of

heat , at normal body temperature and without sweating.

Comfort zones evaluated in India is given:-Human feeling temperature

Pleasant and cool 69*F or 21*C

Comfortable and cool 69*F -768F or 21*C-24*C

Comfortable 77*F-80*F or 24*C-27*C

Hot and Uncomfortable 81*F + or 28*C +

Intolerably Hot 86*F + or 30*C +

AIR POLLUTION Air pollution is defined as any atmospheric condition

in which certain substances are present in such

concentrations that they can produce undesirable

effects on man and his environment.

Sources of air pollution:-

I. Natural pollution :- Natural pollution of the

atmosphere occurs due to dust storms eruption of

volcanoes , results of lightning and floods, etc.

II. Industries :- Industrial enterprises emit various

gases and particulate matter such as sulphur

dioxide , nitrogen oxide, cement dust , carbon

monoxide etc.

III. Use of automobiles:-automobiles are the major

sources of air pollution because the number of vehicles

are increasing. The major pollutant emitted by the

automobiles is nitrogen oxide, hydrocarbons, carbon

monoxide.

IV. Chemical fertilizers :-these are used to increase

agriculture production . It produces pollutants like

nitrogen oxide , sulfur dioxide , ammonia and urea dust

which pollute the air in the community.

V. Tobacco smoke:- Smoking in the house and public

places pollute the air . The tobacco smoke emits

nicotine , which is highly injurious.

AIR PLLUTION AND HEALTH

Air pollution affects human health directly as well as indirectly.

The chemical contaminants enter human syse=tem mainly

three avenues:-

1. Inhalation :- Breathing the air-borne contaminants , which

find their way into the lungs.

2. Absorption :-many gaseous and liquid materials are

absorbed to a limited extend through skin. Phenol, cresol,

aniline etc. are example of materials which enter into body

by skin absorption.

3. Ingestion:- ingestion of toxic materials may result from

sources such as food , drinks , ect. Disease caused by

prolonged exposure to dust as indicated in table

Dust Dust disease

1. silica Silicosis

2. Coal Pneumoconiosis

3. Asbestos Asbestosis

4. Cotton Byssinosis

5. Bagasse Bagassosis