A Handbook of Health - Woods Hutchinson (whitelam books txt) 📗

people, rapidly becomes poisonous and unwholesome. As we breathe on an average about eighteen or twenty times to the minute when we are grown up, and twenty-five to thirty times a minute when we are children, you can readily see how quickly the air in an ordinary-sized room will be used up, and how foul and unfit for further breathing it will become from being loaded with these bad-smelling lighter gases, with the carbon "smoke," with heat, and with moisture. The only way in which a room can be kept fit for human beings to breathe in is to have a draught, or current of air, pouring into it through open windows, or open doors, or ventilating shafts, at least as rapidly as it is being breathed by the persons who occupy that room. By hundreds of tests this has now been found to be on an average about four bushels a minute for each person, and any system of proper ventilation must supply this amount of air in order to make a room fit to sit in.

If a man, for instance, accidentally gets shut into a bank-vault, or other air-tight box or chamber, it will be only a few minutes before he begins to feel suffocated; and in a few hours he will be dead, unless some one opens the door. A century ago, when the voyage from Europe to America was made in sailing vessels, whenever a violent storm came up, in the smaller and poorer ships the hatches were closed and nailed down to keep the great waves which swept over the decks from pouring down the cabin-stairs and swamping the ship. If they were kept closed for more than two days, it was no uncommon thing to find two or three children or invalids among the unfortunate emigrants dead of slow suffocation; and many of those who were alive would later have pneumonia and other inflammations of the lungs. On one or two horrible occasions, when the crew had had a hard fight to save the ship and were afraid to open the hatches even for a moment, nearly one-third of the passengers were found dead when the storm subsided. So it is well to remember that we are fearfully poisonous to ourselves, unless we give nature full chance to ventilate us.

There are also other ways in which the air in houses may be made impure besides by our own bodies, but none of them is half so serious or important. All the lights that we burn in a house, except electric ones, are eating up oxygen and giving off carbon dioxid. In fact, a burning gas jet will do almost as much toward fouling the air of a room as a grown man or woman, and should be counted as a person when arranging for ventilation.

If gas pipes should leak, so that the gas escapes into a room, it is very injurious and unwholesome—indeed, in sufficient amounts, it will suffocate. Or, if the sewer pipes in the walls of the house, or in the ground under the cellar, are not properly trapped and guarded, sewer gas may escape into the house from them, and this also is most unwholesome, and even dangerous.

Cellar and Kitchen Air. Houses in which fruit and vegetables are stored in the cellar become filled with very unpleasant odors from the decay of these. Others again, where the kitchen is not properly ventilated, get the smoke of frying and the smell of cooking all through them. But such sources of impurity, while injurious and always to be strictly avoided, are neither half so dangerous when they occur, nor one-tenth so common as the great chief cause of impure air—our breaths and the other gases from our bodies, with the germs they contain.

Drafts not Dangerous. Now comes the practical question, How are we to get rid of these breath-poisons? From the carelessness of builders, and the porous materials of which buildings are made, most houses are very far from air-tight, and a considerable amount of pure air will leak in around window-casings, door-frames, knot-holes, and other cracks, and a corresponding amount of foul air leak out. But this is not more than one-fifth enough to keep the air fresh when the rooms are even partially occupied, still less when they are crowded full of people. As each individual, breathing quietly, requires about four bushels of air (one and a half cubic yards) a minute, it is easy to see that, when there are ten or more people in a room, there ought to be a steady current of air pouring into that room; and when there are twenty or even forty people, as in an average schoolroom, the current of air (provided there is one) must move so fast to keep up the supply that the people in the room begin to notice it and call it "a draft." It would be difficult to ventilate a room for even four or five persons without producing, in parts of it, a noticeable draft of air. In fact, it is pretty safe to say that, if somebody doesn't feel a draft the room is not being properly ventilated. At one time this was considered a very serious drawback—drafts were supposed to be so dangerous. But now we know that a draft is only air in motion, and that air in motion is the only air that is sure to be pure. There is nothing to be afraid of in a draft which is not too strong, if you are clean outside and in, and reasonably vigorous. If the draft is too strong, move away from the window or the door. Colds are very seldom caught from the cold, pure air of a draft, but nearly always from the germs, or dirt, in the still, foul air of a tightly closed room. This fact has swept away the chief objection to the direct, or natural, method of ventilating through open windows.

Methods of Ventilation. Fortunately, as often happens, the simplest and most natural method of ventilation is the best one. Open the windows, and let the fresh air pour in. If there be any room which hasn't windows enough in it to ventilate it properly, it is unfit for human occupation, and is seldom properly lighted. Most elaborate and ingenious systems of ventilation have been devised and put into our larger houses, and public buildings like libraries, court-houses, capitols, and schools. Some of them drive the air into each room by means of a powerful steam, or electric, fan in the basement; others suck the used-up air out of the upper part of each room, thus creating an area of low pressure, to fill which the fresh air rushes in through air-tubes or around doors and windows. They have elaborate methods of warming, filtering, and washing the air they distribute. Some work fairly well, some don't; but they all have one common defect—that what they pump into the rooms is not fresh air, though it may conform to all the chemical tests for that article. "The proof of the pudding is in the eating," and fresh air is air that will make those who breathe it feel fresh, which the cooked and strained product of these artificial ventilating systems seldom does.