Abstract
Building occupants are increasingly concerned about the presence of chemicals in indoor air, their contribution to “tight-building syndrome,” and their effects on health. Chemical measurements were made in 17 buildings in Quebec to determine contaminant sources and airborne concentrations and to establish their interrelation. The feasibility of using carbon di-oxide as an air quality indicator for other airborne chemical contaminants also was evaluated. The results indicate that chemicals present in office buildings can arise from both outside and inside; that the emission sources can be continuous, instantaneous, or local; and that some contaminants are related to occupancy and occupant activity. Airborne concentrations of chemical contaminants are lower than the recommended values for an industrial environment, but for dust, carbon monoxide, and carbon dioxide, some results are higher than the values recommended for nonindustrial indoor air. Although contaminant levels are low, the presence of these chemicals in indoor air is of concern, because many of them have individually recognized toxic effects that can be amplified by the others. These synergetic effects, as well as the long-term ones regarding exposure to multiple contaminants present in small amounts, are unknown. Carbon dioxide can be used as an air quality indicator for contaminants related to occupant activity. If local contaminant emission sources (internal or external) are present, they have to be evaluated separately.