Читать книгу American Red Cross Text-Book on Home Hygiene and Care of the Sick - American National Red Cross - Страница 28

—Ventilation has a direct bearing on health, although, contrary to former belief, the actual amount of oxygen in the air is not ordinarily the most important factor; even badly ventilated rooms contain more than enough oxygen to support life. The factors of prime importance in ventilation are temperature, humidity, air movement, and the number of persons in a given space since the greater the distance from one another the less is the probability that diseases will be spread.

Room temperature should not be above 70° F. and, except for the aged or sick, it is better to be between 60° and 65°. Some moisture in the air is desirable; the amount needed is from 50% to 55% of the total moisture that the air can hold at a given temperature. We have no apparatus to decrease humidity in the air of houses, and in summer we are obliged to endure humidity, if excessive, no matter how uncomfortable we may be. But in winter the air in most houses is too dry, so that the mucous membranes of the nose and throat often become irritated and susceptible to infection. Most heating systems, particularly in small buildings, make no provision for supplying moisture. Keeping water in open dishes on or near radiators is often recommended, and would greatly improve the condition of the air, if people remembered to keep the dishes filled.

The following is a simple but effective device to increase humidity: Roll an ordinary desk blotter into a cone about 8 inches in diameter at the base, and keep it constantly submerged for about one inch in a dish of water. The water rises to the top of the blotter and a large surface for evaporation is thus afforded.

Fig. 7.

Stagnant air is harmful. Air should be in constant though not necessarily perceptible motion. Air about the body, if motionless, acts like a warm moist blanket, preventing the passage of heat from the body.

The three factors, heating, humidity, and air motion, must be considered together. Every person requires each hour about 3000 cubic feet of air, and the problem of heating and ventilating is that of providing this amount in gentle motion, at a temperature of about 65° F., and of humidity from 50–55%. Higher temperatures and stagnant air cause disinclination to work, headache, nausea, restlessness, or sleepiness, and if continued are likely to result in loss of appetite, and anemia. The tuberculosis movement has clearly shown the benefits both for the sick and the well of living in the open air, and has caused great and beneficial changes within a generation. The more time spent in the open air the better; since however most persons who work must spend the greater part of the day indoors, ventilation is a matter of great importance.

Although fresh air enthusiasts are still too few, yet some go to the extreme and think that because cool air in motion is good, the colder the air and more violent the motion the better. On the contrary, chilling the whole body or a part of the body lowers resistance. Draughts of air have no bad effects upon persons in good health, particularly those accustomed to changes in temperature. But draughts are likely to be injurious to aged or sick persons and babies, by diminishing their resistance to such infections as common colds and pneumonia. It should be remembered that draughts or cold alone cannot cause colds; the specific germs must be present.