Effect Of Air Conditioning On The Health Of Workers
( Originally Published 1936 )
A great deal of importance has been placed on the benefits of air conditioning to health. Experiments conducted in China and India, where high temperatures and humidities are continuous, by several large industries, resulted in the conclusion that continuous heat affected not only the physical condition, but also had some effect on the glands. Rest did not stay the effect of the climate on old residents in the area, but eight hours of comfortable temperature, either while working or resting, kept the subjects up to par.
Other suggestions are that as an even distribution of the blood is the most healthful, that high temperatures causing the blood to concentrate at the surface, will deprive the heart, stomach, liver, kidneys and other organs of their normal blood supply and impair their efficiency. We do know the heart must work harder to send more blood to the surface of the body, causing a definite strain. It is thought the feeling of lassitude and enervation experienced in warm weather is due to an insufficient supply of blood to the brain. To these conditions are attributed heat stroke and prostration. And summer cramps are attributed to the fact that excessive perspiration deprives the body of necessary salts.
It is fair to assume that in any disease the patient's chance of recovery will be much better if his strength is not needed to resist excessive temperatures, but for definite relief or cure of disease the only positive proof we have is in connection with pollen hay fever or asthma. The spray or filter removing pollen from the air gives the patient partial or complete relief so long as he remains in the conditioned area.
The benefits of air conditioning to industry are too numerous to mention. One or two examples illustrate the point very well. In an air conditioned office employing 45 people, a reduction of 23 per cent in lost time took place the first year the system was installed. In another, the decrease in lost time was 50 per cent. In still a third, an office employing over 100 bookkeepers, the percentage of errors which increased greatly in the summer months, decreased after air conditioning was installed to the level of the rest of the year, and remained constant the year around.
In a factory installing an air conditioning system, the defective products were reduced from 4 per cent to 1 per cent. Before air conditioning, for 75 of the summer days, an average of 50 girls per day became sick or fatigued and quit at noon. After air conditioning only five girls were out half-days during the 75 days. After the air conditioning system was installed 100 fewer girls left during the summer for lighter, cooler work, greatly reducing the training expense. In this latter case the company, charging all possible cost to air conditioning, estimated an actual saving of approximately $24,000 per year. Air conditioning in factories has proved so successful that some of them are being erected now without any windows or openings except doors, the artificial light furnishing the sunlight requirements and air conditioning the required temperatures.
WHAT IS "GOOD AIR"?
The chemical composition of the air we breathe is no longer considered by hygienists to be its most important feature from a health standpoint.
Although the public's belief in the bad effect of carbon dioxide and poisonous exhalations dies hard!
The modern view is that the important factors are the physical factors-temperature, humidity and air movement.
The old idea of Pettenkofer's that the amount of carbon dioxide in a room is a valuable guide to the presence of other harmful factors was brought forward 60 years ago. The modern hygienic viewpoint, based on the work of Haldane and Hill, is that the estimation of the amount of carbon dioxide in the atmosphere does not yield information commensurate with the trouble of making the test.
The discomfort of being in a badly ventilated and stuffy atmosphere results from the body's being unable to rid itself of heat. This comes from improper air movement, temperature and humidity.
Only under the most extraordinary circumstances could the oxygen be so reduced as to affect the health. Indeed, the only natural conditions in which such a thing is possible are mine disasters and ascents to high altitudes. Professor Picard took some oxygen along in his visit to the stratosphere, but he is a specialist in his line and few people are likely to be exposed to his special dangers.
The instrument which the modern hygienist uses to determine the healthfulness of any atmosphere is not a chemical retort or test tube, but a katathermometer. This is a dry thermometer which measures the cooling power of the atmosphere under test.
For efficient work the cooling power of the air must be at a certain level in a room or factory. What this level is has been determined by a large number of experiments and can be stated mathematically, although the figures would not mean anything to a person unfamiliar with the tests.
Science has tested the question of whether you work better with your coat off, and it should be no surprise to anyone who has tried it to learn that the cooling power of the atmosphere comes into play better with the coat off and hence that maneuver makes for more efficiency.
The greater comfort and freshness of outdoors is not at all the difference in the amount of "ozone" out there as in this cooling power of the open air.