Ammonia (NH3)
Normally there is only a trace of ammonia in air. It is produced by the decomposition of organic matter. This accounts for the larger amount being found in the air near the ground. Ground air may contain ammonia in sufficient quantity to be perceptible to the senses.
Other Constituents
Hydrogen peroxide is a very active oxidizing agent. Rain water and snow contain very small traces of it. Hydrogen peroxide is not constant in air, but may be found in very small quantities.
Air also contains small traces of helium, krypton, neon, xenon, which have no important bearing from a hygienic standpoint. Nitric, sulphuric and other acids will at times be found in the atmosphere. These acids are formed principally from industrial processes and will, therefore, be found near industrial centers, rather than in the open country or at sea.
AIR PRESSURE
Normal Air Pressure
Ordinary air pressure on the surface of the earth at sea level is, in round numbers, fifteen pounds to the square inch. It has been found that the average sized man is exposed to about 34,000 pounds of pressure. This pressure may be increased or decreased, and if the change takes place gradually so that Innate Intelligence will have time to adapt the body to the change, no harm will result. There is a limit, however, either in a decrease or in an increase of pressure to which the body may be adapted.
This intellectual adaptation obtains in every tissue cell of the body as well as in all of its secretions and chemicals so it can be seen that any sudden change in the atmospheric pressure will disturb the equilibrium of the entire body.