Aerosol

“ Wind clears the air of impurities, and is only harmful when it carries dust with it, or when it is so strong that it impedes the respiration or bodily movements. Very weak persons get out of breath easily when battling against the wind.
Town Air.—Even the outdoor air of towns has its full quota of oxygen,—21 per cent.,—and so is healthier than indoor air. The carbonic acid in the air varies from 0.2 to 0.6 per cent. Among the impurities of the air are smoke, fog, and dust. ”

“ The same uniformity is apparent whether we examine the air of the polar regions or that of the tropics; whether we collect it in the densely populated city or in the untrodden forest. This fact seems all the more wonderful when we consider the contaminating influence of the countless exhalations that are continually rising into the atmosphere. The clouds of smoke poured forth by our chimneys, the expired breath of animals, and the gases that proceed from decaying matters, do not perceptibly disturb the equilibrium of the constituents of the atmospheric ocean. ”

“ Then there was a society which objected to the use of what they called contaminated air in the air-tubes, by which expression they meant its admixture with oxygen for breathing purposes, which had proved such a boon to the subaqueous inhabitants. Those worthy people contended that the air as it existed in the atmosphere was the proper air for man to breathe, and that its admixture with any foreign ingredient whatsoever was prejudicial, if not to the body, at all events to the mind of those who used it in that state. ”

“ Without atmospheric dust, we should not have the glorious cloud scenery which we at present enjoy. We should have no haze in the atmosphere, we should have no twilight. Darkness would come as soon as the sun passed below the horizon.
The relative humidity of the air has a great effect on the dust by increasing the size of the particles of water vapor and so increasing the haze. The number of dust particles rapidly decreases with the amount of moisture present. ”

“ The slightest change in the purity of the atmosphere, though it may be too slight for recognition by chemical analysis in the laboratory, is sure to be detected by its effects upon the nicer chemistry of the human system, for it is known to be productive of disease and death. No chemical tests are sensitive enough to tell us what those changes are, but experience has taught us the necessity of ventilation in our buildings, of circulation through our groves. The cry in cities for fresh air from the mountains or the sea, reminds us continually of the life-giving virtues of circulation. ”

“ The winds and certain properties of the atmosphere constantly remove much of the impure air, and bring in a pure supply; but the crowding together in many parts of a town is so great, and the production of poisonous matter goes on so continuously, that instead of each breath containing its full proportion of oxygen, the place of that gas is taken up to some extent by what is actually hurtful to life. When this is the condition of the atmosphere outside the dwelling, it is necessarily much worse within it, for there the displacement of impure air by pure cannot take place so rapidly. ”

“ It is almost impossible in an ordinary room to make the smoke go down to the floor without a very violent effort. In all ordinary expulsion it would be noticed that the smoke ascends, and quickly becomes disseminated through the air of the room. The scientific fact is that air exhaled from the lungs is, at the moment of exhalation, equal in weight to pure air at a temperature of 90 deg. Fahr. And until the exhaled air has parted with so much of its heat as to become heavier than pure air at this temperature, it will rise in a normally pure atmosphere."—Builder (April 30th, 1898) . ”

“ More disease germs exist in river water in winter than in summer, which may be due to the greater disinfecting power of the sun’s rays during summer.
Dust Motes of the Air. As the earth pursues its course about the sun, dust rains into its atmosphere from outer space. Meteors that are burned through the heat generated by striking into our air contribute to the supply, as do volcanoes, combustion, spray from the ocean, and matter lifted up by the action of the wind. ”

“ Aer, L. (from αηρ Gr.) ; Luft, Ger.; Atmospheric Air; The Atmosphere. This name was formerly given to any aëriform body; thus, by the old chemists ammoniacal gas was called alkaline air; oxygen,—dephlogisticated, vital, or empyreal air; carbonic anhydride (carbonic acid) , fixed air; hydrogen, inflammable air; heavy carbonetted hydrogen, olefiant gas, heavy inflammable air; nitrogen,—mephitic, phlogisticated, or nitrous air. At the present time the term air is usually restricted to the gaseous envelope surrounding the solid and liquid parts of our globe. ”

“ These experiments resulted in his discovering the important fact that atmospheric air, after having been corrupted by the respiration of animals, and by the burning of inflammable bodies, is restored to salubrity by the vegetation of plants; and that, if the air is exposed to a mixture of sulphur and iron-filings, its bulk is diminished between a fourth and a fifth, and the residue is both lighter than common air and unfit to support life; this residue he termed 'phlogistic air,' afterwards called azotic or nitrogen gas. ”

“ During the night plants only give off carbonic acid.
2. The Fall of Rain clears the atmosphere of any solid particles contained in it, the impurities being transferred to rain-water which generally contains an appreciable amount of ammonia as well as other impurities. Rain not only washes and purifies the air, but by washing the ground, diminishes dust, and prevents its escape into the air. It is the great natural scavenger.
3. Ventilation—that is, the interchange of pure and impure air, is constantly being effected. ”

“ In ordinary breathing, 30 cubic inches of air pass in and out at every breath, and adults breathe about fifteen times every minute. But the warm lung-surface repels the colder dust-particles, and the continuous evaporation of moisture from the surface of the air-tubes prevents the dust from alighting or clinging to the surface at all. ”

“ Disease germs, poisonous gases, mildew, insects, dust, and dirt have it all their own way in stale, used-up air.
You do not like to wash in water other people have used, but it is far worse to breathe air other people have breathed. Air does not flow in and flow out of the same opening at the same time any more than water does, so you want two openings in a room—an open window to let the good air in, and a fireplace and chimney to let the stale air out, or, where there is no fireplace, a window open both at top and bottom. ”

“ In the beginning of a cold in the head, for instance, the cold air irritates the inflamed mucous membrane of the nose, and causes repeated attacks of sneezing.
217. How the Atmosphere is Made Impure. The air around us is constantly being made impure in a great variety of ways. The combustion of fuel, the respiration of men and animals, the exhalations from their bodies, the noxious gases and effluvia of the various industries, together with the changes of fermentation and decomposition to which all organized matter is liable,—all tend to pollute the atmosphere. ”

“ CONCERNING THE NEED FOR VENTILATION.—The foul air which passes off from the lungs and through the pores of the skin does not fall to the floor, but diffuses itself through the surrounding atmosphere. A single breath will to a trifling but certain extent taint the air of a whole room. [Footnote: This grows out of a well-known philosophical principle called the Diffusion of Gases, whereby two gases tend to mix in exact proportions, no matter what may be the quantity of each.—STEELE'S Popular Chemistry, p. 86, and Popular Physics, p. 52.] A light will vitiate as much air as a dozen persons. ”

“ When Priestley commenced his studies, the current belief was, that atmospheric air, freed from accidental impurities, is a simple elementary substance, indestructible and unalterable, as water was supposed to be. When a combustible burned, or when an animal breathed in air, it was supposed that a substance, "phlogiston," the matter of heat and light, passed from the burning or breathing body into it, and destroyed its powers of supporting life and combustion. ”

“ The burning of any substance occasions the same smell: for the gross fume which arises from them, before they flame, is the inflammable air they contain, which is expelled by heat, and then readily ignited. The smell of inflammable air is the very same, as far as I am able to perceive, from whatever substance of the same kingdom it be extracted. Thus it makes no difference whether it be got from iron, zinc, or tin, from any kind of wood, or, as was observed before, from any part of an animal. ”

“ The air is frequently charged with smoke particles. In a general way, smoke particles are to be considered as a peculiar character of dust. They are peculiarly disagreeable because the particles are generally black in color and consequently render everything on which they settle of a disagreeable black and sooty color. The disagreeable part of smoke from the ventilation standpoint consists of the small particles of carbon which float in the air. ”

“ A dust-laden atmosphere is a germ-laden atmosphere, therefore physicians prescribe for tubercular convalescents conditions in which the air is 90% free from dust. However, the air of the city has been scientifically proven to be as pure as the air of the country. All that is necessary to secure proper lung food is plenty of it,—houses so constructed that the air inside shall be free to go out and the air outside to come in. Air in a closed cage must be mischievous, and what are ill-ventilated rooms but vicious air cages, in which mischiefs of all sorts breed? ”

“ Until the middle of the last century an opinion universally prevailed that the atmospheric air is a perfectly homogeneous and undecomposable body—that there is but one kind of air, that which we breathe, and though in mines, wells, and other deep and solitary places, substances somewhat analogous occur, they are in reality nothing more than vitiated forms of atmospheric air, which has gathered poisonous qualities from mineral exhalations. ”

“ We rightly consider all air, which acts on our senses or our feelings differently from air in the open, to be polluted.
The second way in which we render the air impure on its journey through our houses is that of altering the quantities of its components. We deprive it of oxygen by our respiration, by the burning of lights and fires; we increase its carbonic acid and its water by the activity of our lungs and skin, and by numerous proceedings of the household. ”

“ Now this process will still go on, whether exposed to the atmosphere or not, with this difference, that, by exposing substances which have imbibed the exhalations of the diseased to a free air, the noxious gases will be dissipated as quickly as they are evolved; while, on the other hand, by laying the clothes in a heap, packing them firm in a chest, or making up cloth into small bales, the gases are concentrated into a small space; and woe to the man who first inspires them. ”

“ It will have appeared from my former experiments, that inflammable air consists chiefly, if not wholly, of the union of an acid vapour with phlogiston; that as much of the phlogiston as contributes to make air inflammable is imbibed by the water in which it is agitated; that in this process it soon becomes fit for respiration, and by the continuance of it comes at length to extinguish flame. ”

“ We have already seen, that the atmospheric air is composed of two gasses, or aëriform fluids, one of which is capable, by respiration, of contributing to animal life, and in which metals are calcinable, and combustible bodies may burn; the other, on the contrary, is endowed with directly opposite qualities; it cannot be breathed by animals, neither will it admit of the combustion of inflammable bodies, nor of the calcination of metals. We have given to the base of the former, or respirable portion of the air, the name of oxygen, from οξυς acidum, and γεινομας, gignor ”

“ It is the vitalizing principle in all forms of life. By its chemical union with carbon in the tissues of plants and animals it develops the energy manifested in their movements.
In the free air up to about seven miles high there is no variation in the proportion of oxygen. But variations of marked importance to health and life occur in places where ventilation is restricted, and especially where living creatures exist in closed rooms, and where combustion occurs in confined places. ”

“ We admit raw air, and we warm it most at the critical moment when we send it up the chimney! We freeze our backs and scorch our faces. We sit with our feet in a current of cold air, and our heads are kept in an impure atmosphere, vitiated by human lungs, the products of gas-consumption, and loaded with animal matter. ”

“ In this case, also, the air has never failed to be restored; but then it might be suspected that the melioration was produced by the addition of some more wholesome ingredient. As these agitations were made in jars with wide mouths, and in a trough which had a large surface exposed to the common air, I take it for granted that the noxious effluvia, whatever they be, were first imbibed by the water, and thereby transmitted to the common atmosphere. In some cases this was sufficiently indicated by the disagreeable smell which attended the operation. ”

“ Atmospheric air is a mixture, or compound, according to some, of two gases, oxygen and azote, with carbonic acid; but the proportion of the latter rarely exceeds two per cent, while the quantity of oxygen is about twenty-two. It is a solvent, as well as a vehicle, and hence may contain water, gaseous fluids, &c. Miasmata, which is contained often in the air, are vapours or effluvia, that affect the human system, and bring on diseases, of which the principal are the intermittent, remittent, and yellow fevers, dysentery and typhus. That of the last is generated in the human body itself. ”