Building performance evaluation for indoor air quality using occupant contaminant inhalation and attribution to contaminant sources.

The emissions of building materials like volatile organic compounds and indoor airbornecontaminants such as environmental tobacco smoke expose occupants to hazardowsubstances. Although impacts of indoor air quality problems on human health, comfort, andproductivity are quite large, no adequate evaluation methodology exists to assess contaminantsource control techniques and building equipment systems. Even if instant indoorconcentrations of many contaminants are not always high, continuous exposures to thesecontaminants may cause severe problems such as manifested by the sick building syndrome.This paper proposes a method for evaluating long-term building performance in terms ofindoor air quality. The approach applies exposure assessment but focuses on buildingperformance. It employs the concept of using the total amount of substance inhaled bypersons who occupy the room. This indicator is expressed by kilograms of each con taminantinhaled by persons ever present in the building during its operational life. The values includethe effects of occupant rates. Concrete procedures for deriving variations of the indicators forboth gaseous and particulate contaminants are described in detail. Another concept ofcontribution rates of contaminant sources is introduced both for instant values and on theinhalation basis. Evaluation examples of these indicators for a simple office geometry areshown for particulate matter, carbon dioxide, and formaldehyde. The results of the casestudies strongly suggest the importance of indoor material selection and ventilation strategies.The contribution rate of contaminant sources makes it easier to plan a remedy for bad indoorair quality. The applicability of these indicators and future research requirements are alsodiscussed.