CMHC residential indoor air quality parametric study.

The purpose of this study was to carry out a mathematical modelling analysis of the effect of indoor pollutant source strengths and ventilation rates on the concentration of pollutants. These concentrations are then compared to various human exposure limits and targets. The modelling was carried out for a variety of ages of residential detached housing for a range of Canadian climatic conditions. Although a literature search was performed, pollutant source strength data for housing was not generally available. A few houses had been surveyed for CMHC and had concurrent pollutant concentrations and passive tracer gas air change rate measurements. These were used to establish pollutant source strengths or emission rates. The study was directed at building generated pollutants. Soil gas pollutants and combustion appliance spillage were not modelled in this study. Air change rates including air leakage and mechanical ventilation were estimated using a computerized model. Pollutant concentrations were calculated and analyzed for periods, system types and house types which were potentially undesirable. For some pollutants including Volatile Organic Compounds (VOCs), no established residential exposure limits have been established. Industrial limits and proposed guidelines are discussed relative to the concentrations predicted. Formaldehyde was compared to Canada's exposure guidelines. Emission limits and ventilation strategies appropriate for housing can be developed through this kind of research work. Further work is needed.