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The Need Of Pure Air

Sources: A Handbook Of Health

Free Air is Pure. As air, in the form of wind, actually sweeps all

outdoors, day and night, it clearly is likely to pick up a good many

different kinds of dust and dirt, which may not be wholesome when

breathed into our lungs. Fortunately, nature's great outdoor system of

purifying the air is almost perfect, so that it is only when we build

houses and shut in air from the great outdoor circulation, that dirt

that is re
lly dangerous begins to get into it. Caged air is the only

air that is dangerous. Free-moving air is always perfectly safe to

breathe any hour of the day or night, or any season of the year.

Shut-in and Stagnant Air is Foul. This restless air-gas cannot be

stored outside of the body, any better than it can be inside. For one

thing, it is too bulky; and for another, it begins to become impure in

various ways, as soon as it is shut up. It is the most unmanageable food

that we eat, for we can neither cook it nor wash it like solid food,

nor filter it nor boil it like water, except on a very limited scale. We

can do nothing to it except to foul it, which we do with every breath

that we breathe, every fire that we make, every factory that we build.

Our only chance of safety, our only hope of life, is to connect every

room and every corner of those little brick and mortar boxes, those

caged sections of out-of-doors, that we call houses, with nature's great

system of air supply, All Outdoors. Fortunately, the only thing

needed to make the connection is to open a window--no need to send for a

plumber or put in a meter, and there is no charge for the supply after

connections have been made.

The Enormous Amount of Air. Air outdoors is everywhere, for practical

purposes, absolutely pure, just as water is when it comes down from the

clouds. And like water, its only dangerous impurities are what we put

there ourselves. The purity of outdoor air is due mainly to the fact

that there is such an enormous amount of it, not only the miles and

miles of it that stretch away on every side of us, but nearly thirty

miles of it straight up above our heads; its purity is also due to the

fact that, like water, it is always in motion. When heated by the sun,

it expands; and, in doing so, it rises because it is less dense and

therefore lighter. As soon as the pressure of the air above is lessened,

air rushes in below from all the cooler regions around. This rushing of

air we call a wind. If the low pressure lies to the north of us, the

air rushes northward over us to fill it, and we say the wind is from the

south; if the air is flowing to the south of us, we say the wind is from

the north.

How Air is Purified. In these winds certain small amounts of dust, or

dirt, or leaf mould are whirled up into the air, but these are promptly

washed down again whenever it rains; and the same is true of the smoke

impurities in the air of our great cities. Air is also constantly being

purified by the heat and light of the sunbeams, burned clean in streaks

by the jagged bolt of the lightning in summer, and frozen sweet and pure

by the frosts every winter. So that air in the open, or connected with

the open, and free to move as it will, is always pure and wholesome. But

to be sure of this, it must be eaten alive--that is, in motion.

Stagnant air is always dead and, like all dead things, has begun to


The Carbon Dioxid in the Air. Air, as you will remember (p. 132), is a

mixture of oxygen and nitrogen, and its value in the body is that it

gives off part of its oxygen to combine with the body wastes and burn

them to carbon dioxid. Oddly enough, even pure outdoor air contains tiny

traces of carbon dioxid; but the amount is so very small as to be of no

practical importance, in spite of the fact that every kind of animal

that lives and moves upon the earth is pouring it out from his lungs

every second. The rapidity with which it disappears is due in part to

the rapidity with which it rises and spreads, or is blown, in every

direction; and in part to the wonderful arrangement by which, while

animals throw off this poisonous gas as waste, plants eagerly suck it in

through the pores in their leaves and eat it, turning it into the

carbohydrates, starch and sugar, which, in turn, become valuable foods

for the animals. So perfect is this system of escape, or blowing away,

of carbon dioxid, combined with its being eaten up by plants, that even

the air over our great cities and manufacturing towns contains only the

merest trifle more of carbon dioxid than that over the open country. Its

other smoke-impurities, dirts and dusts, escape, or are blown away so

rapidly that they are seldom thick enough to be injurious to health,

except in the narrowest and darkest streets; so that it is always safe

to open your windows wide for air, wherever you may live. The principal

danger from smoke is that it cuts off the sunlight.

The Necessity for Ventilation--Impurities of Indoor Air. The worst

impurities in air are those that come from our own breaths and our own

bodies; and, unexpectedly enough, carbon dioxid is not one of them. In

spite of hundreds of experiments, we do not yet know exactly what these

impurities are, though they are doubtless given off from our lungs, our

skins, our mouths, and teeth, especially if the latter are not kept

clean and sweet, but left dirty and decaying.

We do know, however, to a certainty that air shut up in a room, or

house, with 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


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.

If they could be combined with the natural, window system of

ventilation, they would be less objectionable; but the first demand of

nearly all of them is that the windows must be kept shut for fear of

breaking the circuit of their circulation. Any system of ventilation, or

anything else, that insists on all windows being kept shut is radically

wrong. It is only fair to say, however, that most of these systems of

ventilation attempt the impossible, as well as the undesirable thing of

keeping people shut up too long. No room can be, or ought to be,

ventilated so that its occupants can stay in it all day long without

discomfort. In ventilating, we ought to ventilate the people in the

room, as well as the room itself. This can only be done successfully by

turning the people out of doors, at least every two or three hours if

grown-ups, and every hour or so if children. That is what school

recesses are for, and they might well be longer and more frequent.

The first and chief thing necessary for the good ventilation of houses

and schools is plenty of windows, which are also needed to give proper

light for working purposes, and to let in the only ever-victorious enemy

of germs and disease--sunlight.

Secondly, and not less important, the windows should fit properly, and

be perfectly hung and balanced, so that the sash will come down at a

finger's touch, stay exactly where it is put, and go up again like a

feather, instead of having to be pried loose, wrested open, held in

place with a stick, and shoved up, or down again, only with a struggle.

The windows to the left of the pupils cannot, of course, be shown in the

picture, but it can be seen that the lighting of the room is chiefly

from that side. Notice that the windows are both down from the top and

up from the bottom.]

There should be, if possible, windows on two sides of every room, or, if

not, a large transom opening into a hall which has plenty of windows in

it. With this equipment and a good supply of heat, any room can be

properly ventilated and kept so. But it will not ventilate itself.

Ventilation, like the colors of the great painter Turner, must be mixed

with brains; and those brains must be in the room itself, not down in

the basement. In the schoolroom, each teacher and pupil should regard

the ventilation of the room as the most important single factor in the

success of their work. The teacher has a sensitive thermometer and guide

in, first, her own feelings and, second, the looks and attention of her

pupils. There should be vacant seats or chairs in every room so that

those too near the window in winter can move out of the strong current

of cold air.

Windows should reach well up toward the ceiling and be opened at the

top, because the foul air given off from the lungs at the temperature

of the body is warmer than the air of the room and consequently rises

toward the ceiling. It is just as important in ventilation to let the

foul air out as to let the fresh air in. In fact, one is impossible

without the other. Air, though you can neither see it, nor grasp it, nor

weigh it, is just as solid as granite when it comes to filling or

emptying a room. Not a foot, not an inch of it can be forced into a room

anywhere, until a corresponding foot or inch is let out of it somewhere.

Therefore, never open a window at the bottom until you have opened it

at the top. If you do, the cold fresh air will pour in onto the floor,

while the hot foul air will rise and bank up against the ceiling in a

layer that gets thicker and thicker, and comes further and further down,

until you may be actually sitting with your head and shoulders in a

layer of warm foul air, and your body and feet in a pool of cool pure

air. Then you will wonder why your head is so hot, and your feet so


Currents and Circulation of Air. In fact, this tendency of hot air to

rise, and of cold air to sink, or rush in and take its place, which is

the mainspring of nature's outdoor system of ventilation, is one of our

greatest difficulties when we wall in a tiny section of the universe and

call it a room. The difficulty is, of course, greatest in winter time,

when the only pure air there is--that out of doors--is usually cold.

This is one of the few points at which our instincts seem to fail us.

For when it comes to a choice between being warm or well ventilated, we

are sadly prone to choose the former every time. Still we would much

rather be warm and well ventilated than hot and stuffy, and this is

what we should aim for.

The main problem is the cost of the necessary fuel, as it naturally

takes more to heat a current of air which is kept moving through the

room, no matter how slowly, than it does a room full of air which is

boxed in, as it were, and kept from moving on after it has been warmed.

The extra fuel, however, means the difference between comfort and

stuffiness, between health and disease. Fortunately, the very same cold

which makes a room harder to heat makes it easier to ventilate. When air

is warmed, it expands and makes a low pressure, which sucks the

surrounding cooler air into it, as in the making of winds; so that the

warmer the air inside the room, or the colder the air outside of it,

which is practically the same thing, the more eagerly and swiftly will

the outdoor air rush into it. So keen is this draft, so high this

pressure, that some loosely-built houses and rooms, with only a few

people in them, will in very cold weather be almost sufficiently

ventilated through the natural cracks and leaks without opening a window

or a door at all. And what is of great practical importance, an opening

of an inch or two at the top of a window will admit as much fresh air on

a cold day as an opening of a foot and a half in spring or summer, so

swiftly does cold air pour in.

Bearing this in mind, and also that it is always best to ventilate

through as many openings as possible, both to keep drafts of cold air

from becoming too intense, and to give as many openings for the escape

of the foul air as possible, there will be little difficulty in keeping

any room which has proper window arrangements well ventilated in winter.

An opening of an inch at the top of each of three windows is better than

a three-inch opening at the top of one. But you must use your brains

about it, watching the direction of the wind, and frequently changing

the position of the window sashes to match the changes of heat in the

room, or of cold outside.

No arrangement of windows, however perfect, is likely to remain

satisfactory for more than an hour at a time, except in warm weather.

This watchfulness and attention takes time, but it is time well spent.

Eternal vigilance is the price of good ventilation, as well as of

liberty; and you will get far more work done in the course of a morning

by interrupting it occasionally to go and raise or lower a window, than

you will by sitting still and slaving in a stuffy, ill-smelling room.

Plenty of Heat Needed. Any method of heating--open fireplace, stove,

hot air, furnace, hot water, or steam--which will keep a room with the

windows open comfortably warm in cold weather is satisfactory and

healthful. The worst fault, from a sanitary point of view, that a

heating system can have is that it does not give enough warmth, so that

you are compelled to keep the windows shut. Too little heat is often as

dangerous as too much; for you will insist on keeping warm, no matter

what it may cost you in the future, and a cold room usually means

hermetically sealed windows. Remember that coal is cheaper than colds,

to say nothing of consumption and pneumonia.

Ventilating the Bedroom. The same principles that apply to ventilating

a living-room or day-room apply to ventilating a bedroom. Here you can

almost disregard drafts, except in the very coldest weather, and, by

putting on plenty of covering, sleep three hundred days out of the year

with your windows wide open and your room within ten degrees of the

temperature outdoors. You need not be afraid of catching cold. On the

contrary, by sleeping in a room like this you will escape three out of

four colds that you usually catch. Sleeping with the windows wide open

is the method we now use to cure consumption, and it is equally good to

prevent it.

No bedroom window ought to be closed at the top, except when necessary

to keep rain or snow from driving in. Close the windows for a short time

before going to bed, and again before rising in the morning, to warm up

the room to undress and dress in; or have a small inside dressing-room,

with your bed out on a screened balcony or porch. But sleep at least

three hundred nights of the year with the free air of heaven blowing

across your face. You will soon feel that you cannot sleep without it.

In winter, have a light-weight warm comforter and enough warm, but

light, blankets on your bed, and leave the heat on in the room, if

necessary--but open the windows.