AIR IMPURITIES-DUSTS, FUMES, AND GASES

CHARLES BAskerville

College of the City of New York.

The nature and extent of air impurities discussed in this paper are dependent upon local conditions. For our purposes these air impurities may be classified under three heads: namely, (1) dusts, (2) fumes, and (3) gases. These divisions are not exclusive, as fumes in abundance may become dusts; for example, a sudden escape of white arsenic fumes results in a cloud of dust. Again, smelter fumes (mainly sulfur dioxid), much diluted, may be classed as gaseous. The classification, therefore, is neither specific nor dependent upon inherent properties of the materials. It is merely a convenience and must admit of a broad and liberal interpretation. A technical discussion as to proper lines of differentiation would be of little profit and less interest.

INDUSTRIAL DUSTS

It is well known that various industrial dusts cause irritation of the respiratory passages and of the eyes and skin of workmen. Such dusts may be considered in three classes: namely,

I. Insoluble inorganic dusts.-This class includes metals (antimony, arsenic, type-metal, brass, bronze, copper, aluminum, iron, steel, lead, manganese, vanadium and ferro-vanadium, silver, tin, zinc, and solder) in a state of fine division (dusts, atomized metals, metallic powders); flue dusts; various ore dusts (iron ore, etc.); silica, sand, emery, flint, glass powder; carbon, graphite, diamond, coal, soot; brick dust, marble, granite, cement, terra-cotta; lime, gypsum, plaster, meerschaum; phosphates, guano, etc.

Fibrosis of the lungs may result from the inhalation of silicious or metallic particles; for example, we have "potter's asthma" and "grinder's phthisis" (chronic catarrhal bronchitis among knifegrinders). Pneumonia has been reported as frequent among workmen in blast-furnaces, in part owing, directly or indirectly, to the

inhalation of slag dust; cardiac dilation is said to occur among workmen in slate quarries; ankylostomiasis among brickmakers, miners, etc.; and recurrent inflammation of bone with hypertrophy among pearl-dust workers.

Hellthaler1 has shown the high rate of death among various classes of metal workers in America who are apparently in ignorance of the peculiar dangers of their occupations; and Prinzing2 has demonstrated the high death rate from phthisis among steel grinders and other workmen at Solingen, Germany, for the years 1885 to 1895. It is certain that the inhalation of iron dust may diminish in time the respiratory efficiency of the lungs through a loss in their elastic property; or may reduce the resistance of the organs to invasion by harmful bacteria; or may infect the lungs through a transportation of disease germs to places favorable for their inoculation. The disease known as siderosis exists commonly among metal polishers, knife-grinders, and others engaged in metal working. The earliest symptoms of this disease are, according to Soper, catarrh and bronchitis, but shortness of breath is pronounced by all authorities to be the most characteristic symptom. Eventually there follows what appears to be phthisis without the presence of tubercle bacilli, yet genuine infective phthisis is the most common cause of death. The effects may be delayed for years, but metal working is indeed a dangerous occupation; undoubtedly many die from infectious pulmonary diseases who do not know that the breathing of dusty air has led to their infection.

With the development of rapid transit systems in modern cities, it may be well to direct attention to a new and specific form of city dust investigated by Dr. Soper, who found that the average weight of dust in subway air was 61.6 mg. per 1,000 cubic feet of air, or 2.25 mg. per cubic meter. The figures for the streets were 1.83 mg. per cubic meter. The subway dust was found to consist chiefly of angular particles of iron, but no case of siderosis seemed to have been reported.

2. Soluble inorganic dusts.-This class comprises such substances

'Hellthaler, "The Death Claims." The Independent, December 27, 1906, v. 61:1560.

'Prinzing, Handbuch der Medizinischen Statistik, 1906, p. 489. 'Soper, The Air and Ventilation of Subways, 1908, p. 205.

'Ibid., p. 200.

as are likely to be swallowed and absorbed, and includes: metal particles (lead, brass, copper, zinc, arsenic, mercury, and silver) and soluble inorganic salts. Many dusts of this class are dangerous, not only because of their irritating or poisonous properties, but also because of their inflammability,-e. g., potassium chlorate.

3. Organic dusts. This class comprises sawdust, fur, skins, feathers, broom and straw, grain and flour, jute, flax, hemp, cotton, wool, carpet dust, street sweepings, tobacco and tobacco-box dust, hides and leather, felts, rags, paper, horsehair, etc.

As representative diseases caused by organic dusts we have: "flaxdresser's disease", a kind of pneumonia due to the inhalation of particles of flax; pneumokoniosis due to the inhalation of dust by gannister workers; alkaloidal poisoning from African boxwood by workmen engaged in shuttle making; and malignant pustule and a febrile disease among rag-sorters. As in the other classes, the components of this class of dusts are all irritating to the respiratory tract and to the eyes, and especially are they capable of forming inflammable, and even explosive mixtures with air. In addition, there are various trade eczemas, and anthrax has been frequently reported among wool-sorters.

The solution of the industrial dust problem presents many difficulties. Undoubtedly, however, disease from dust may be much reduced by the following procedures:

(a) Those engaged in the following occupations should wear "workmen-respirators": sorting rags in paper factories; workmen on threshing machines; millers; batch-mixers in glass factories; stonecutters and sculptors; and all those working in factories where the air is contaminated with irritating or poisonous dust.

(b) Those employed in the manufacture of oxidizing agents and lead workers should be compelled to change their clothes before leaving the factory. This is done now in some works in this country.

(c) Glasses for the protection of the eyes of workmen should be looked upon as necessary in plants where irritating dusts are unavoidable.

(d) The dust on the floors of printing, type-casting, metalworking, and other establishments may be laid by means of certain useful preparations. Heise considers those consisting entirely of non-drying (mineral) oils to be the best for the purpose.

'Heise, Arb. Kais. Gesundh.-Amt, 1909, v. 30:93.

Where vapors are likely to occasion industrial poisoning, ventilation will serve to prevent their accumulation; but in the case of dusts, economic considerations often render such a procedure difficult except, of course, as the maintenance of normal ventilation assists in their elimination.

NOXIOUS FUMES, GASES, AND VAPORS

The air of cities and towns where chemical manufactories exist is often contaminated with noxious gases of industrial origin which are dangerous to the health of the workmen employed in the industries. The usual gases which give rise to complaint in manufacturing localities are the following: chlorin, which is emitted by pottery kilns and ceramic-products manufactories, and from plants for the electrolysis of halides; hydrogen chlorid, which is produced by the combustion of coal, and by pottery kilns, ceramicproducts manufactories (partly from the coal and partly from the clay), nickel and cobalt smelting, platinum refining, glass manufactories, fertilizer manufactories, the chlorid of lime industry, and alkali manufactories; sulfur dioxid and sulfuric acid, which result from the combustion of coal, coke, petroleum, and gas, copper smelting, bleaching operations, etc.; fluorides and hydrofluoric acid, which are emitted from acid phosphate and heavy chemical plants; hydrogen sulfid, from chemical works, especially those which produce ammonia; carbon monoxid, which is emitted from iron furnaces and from copper smelters; organic vapors, from, for example, glue refineries, bone burners, slaughter and packing houses; zinc fumes from zinc smelters and from brass foundries; arsenical fumes from copper smelters; phosphoric fumes from match manufactories; and carbon disulfid and sulfur chlorid from some rubber works.

Lehmann" compiled the accompanying table from the reports of many investigators, to show at what concentrations the various common industrial gases are capable of producing immediate and observable effects upon health. The destructive action of fumes in the vicinity of chemical plants is generally due, however, to the presence of sulfurous acid, sulfuric acid, or hydrochloric acid; and this table is given on account of the occupational hazards on the part of workmen employed in chemical manufactories and smelters.

Lehmann, Methoden der Praktischen Hygiene, 1901, p. 174.

Of the gases which affect the respiratory passages and eyes the most important are the following: illuminating gas, gases from coke and coal; carbon monoxid; carbon dioxid (in brewing, baking, and the manufacture of aerated waters); chromic acid; chlorin; sulfuric, hydrochloric and nitric acids, and nitrogen oxids (in acid factories, heavy chemical works, engraving, etching, lithographing, etc.); mercury cyanid; heated lead; ammonia; naphtha and benzine (petroleum refineries and dry-cleaning establishments); arseniuretted hydrogen (copper refineries); sulfur, hydrogen sulfid, sulfur dioxid, and carbon disulfid, sulfur chlorid, nitrous gases, hydrocyanic acid; smoke (fire extinguishing); and the vapors of various organic compounds and substances (tar, creosote, carbolic acid, petroleum and its products, methyl alcohol, fusel-oil, varnish solvents, dinitrobenzol, nitroglycerine, formaldehyde and formic acid, pyridin, etc.). In addition to irritating the respiratory tract and eyes, such substances as the halogens, mineral acids, formic acid, alkalies, creosote and carbolic acid, various dyes, etc., cause injuries to the skin, giving rise to burns, eczema, fissures, ulcers, etc. It has been said that workmen in by-product coke plants, coal-tar color works, and in the roofing and paving industries are troubled with epitheliomatous cancer or ulceration of the skin or of the corneal surface of the eye, owing to constant exposure to pitch and tar compounds; that workers with chromates, tanners, and dyers have "chrome ulceration" of the skin; and that there are various trade eczemas, often of a troublesome nature.

Virtually no accidents have been recorded with hydrogen chlorid gas, and accidents with hydrocyanic acid gas and arseniuretted