The waste products of life and industrial processes that interfere with indoor occupations are :

(a) Carbon dioxide and moisture from the lungs and skins of animals.

(6) The products of combustion from lamps, gas burners, and other artificial lights.

(c) Gases that are the products of cooking and manufacturing processes.

(d) Irritating and poisonous dusts and gases.

The human body is constantly giving off heat, carbon dioxide, and perspiration. The heat is due to the chemical combination of the oxygen in the air we breathe with the carbon of the body. The products formed are heat and carbon dioxide. The heat given off keeps the temperature of the body at about 98 2/5° F. As we are constantly breathing, there is a continual supply of heat which would increase the temperature of the body above normal, unless it were radiated in this manner to the air and surrounding objects. Some of the heat is given off to the air in immediate contact with the body, by conduction, and some is lost by evaporation and perspiration.