Effect of ventilation rate on contaminant emission rates from diffusion-controlled materials

The contaminant emission rate is an important parameter describing the potential for materials to affect indoor air quality through the release of volatile organic compounds (VOCs). Emission rates have traditionally been inferred from gas-phase concentration measurements obtained through chamber studies. However, models suggest that the rate at which VOCs are emitted by diffusion-controlled materials may be influenced by ventilation rates. This study describes an emissions model developed for diffusion-controlled materials and shows how emission rates are theoretically related to ventilation rates. Small chamber experiments were conducted to experimentally determine the effect of ventilation rate on VOC emissions from vinyl flooring. A field study in a house also measured the effect of ventilation rate on VOC emissions. Both laboratory and field results show that an increase in ventilation rate causes an increase in VOC emission rates. The effect is not as pronounced at longer time periods or if the material/air partition coefficient for the specific VOC is small.