Relatively little information exists on the organic contaminants in indoor air, except for some toxic materials in industrial occupational environments. In view of the extended exposures of individuals to indoor air in spaces other than in industry, information on such contaminants is needed before meaningful definitions of the indoor air quality with respect to organic contaminants can be devised. Presently, methods used for the determination of organic contaminants in air fall into two groups:

l. methods used for outdoor air: determination of methane, and all other organics taken together as non-methane hydrocarbons, 2. methods specified by NIOSH for certain harmful substances for which permissible 8-h exposure limits have been defined by OSHA.

The present project was designed to assess the nature and approx. concentrations of organic substances in vapor form which occur in indoor air in typical enclosed spaces. It also sought to determine whether these substances are present in the outside air as well, and thus, are not reducible merely by ventilation.

The project was planned in two phases, the first of which was covered with the development of methodology and initial field trials, while the second dealt with data collection from many sites. This paper presents the results obtained for both phases of this project.