Relationship among Concentrations of Indoor Air Contaminants, Their Sources, and Different Mitigation Strategies on Indoor Air Quality

To ensure that indoor air quality mitigation approaches, such as ventilation, are providing the desired indoor air quality, it is necessary to better understand the varied sources of indoor air contaminants and how different mitigation approaches will affect those sources. This article describes a generalized model that describes the efficacy of different indoor air quality improvement strategies as a function of the primary source(s) of indoor air contaminants of concern. The model is then used as a framework to compare the impact of two different ventilation approaches (a continuous exhaust ventilation strategy compared to a runtime ventilation strategy) on two indoor air compounds (CO2 and formaldehyde) based on primary data gathered in 10 homes in Gainesville, FL. The findings from the Gainesville data suggest that the two approaches provided similar efficacy for reducing CO2 concentrations, but the continuous exhaust system was not as effective at decreasing interior concentrations of formaldehyde, as compared to the runtime ventilation strategy. The simplified, generalized model could be used as a framework to analyze and compare existing detailed modeling and experimental results to bring about a greater understanding of the relative efficacy and tradeoffs of different IAQ mitigation strategies in homes, as well as inform guidance or standards addressing indoor air quality in residential buildings and serve as a decision-making tool for building industry professionals responsible for specifying ventilation systems in homes.