The effect upon most people of breathing over-respired air is to cause heaviness, sleepiness, headache, giddiness, fainting, and sometimes vomiting. When the air is still more impure death may result, as in the case of the 146 prisoners kept in the Black Hole of Calcutta, for a single night, of whom 123 died; and also when 150 passengers were shut up on a very stormy night in a small cabin of the steamer Londonderry, of whom seventy died before morning. The breathing of, impure air day after day causes people to become pale, lose their spirits, strength and appetite, and, as a result, they easily contract any infectious disease which is in the district; and this remark especially applies to consumption, which is particularly common in communities, who live in bad impure air, and the frequency of which tends to diminish in proportion as the air habitually breath-e d is improved.


The solid particles o f carb o n from the smoke of fires, and the fumes of burning sulphur, are harmful to the respiratory apparatus. The gaseous products, such as carbon dioxide and carbon monoxide, may cause death if present in large quantities, and even in small quantities cause pallor, headache, heaviness, and oppression.

Sewer Gas

If an atmosphere is very largely contaminated with sewer gas, death may occasionally result. In smaller quantities this form of impurity will cause sleepiness, headache, loss of appetite, vomiting, diarrhoea, colic, and prostration. Diarrhoea, typhoid fever, and almost certainly diphtheria are not uncommonly set up by sewer gas getting into houses, but at present there is no certain proof that scarlatina can be caused in this way. The air coming from rivers polluted with sewage, or from land on which sewage has been thrown, has been known to cause dyspepsia, and even dysentery.

Other Causes

The air from marshy or newly-broken ground is apt to produce ague. Workmen exposed to the dust arising from various occupations are liable to lung disease. Lead poisoning not unfrequently occurs from lead dust from dyed goods ; wool sorters occasionally get a fatal disease called anthrax from germs coming from the wool of animals which have been similarly affected, and various other diseases arise from the unhealthy air of work-rooms.