Practical methods of reducing airborne contaminants in interior spaces.

Air contaminants include all gases, vapours, liquid droplets and solids, including microogranisms of small size that can be dispersed in air and that are unwanted. Contaminants can be removed by dilution of the air, by deposition of particles on surfaces or by reaction with other materials in air or in space (such as furnishings).< This article discusses in general terms the reduction of contaminants and gives equations of concentrations of contaminants after time t. Discusses types of filters and their effectiveness. Reports field tests using tobacco smoke as the contaminant to test theoretical results and finds excellent agreement. Outlines ways of controlling contaminants. Concludes that it is difficult and expensive to control inside environmental contaminants levels at values less than 20% to 25% of those occurring outside.