The influence of the concealed pollution sources upon the indoor air quality in houses

It is necessary to consider the influence of the pollution sources in the concealed spaces as well as to control emission rate from the interior materials for better IAQ. In this study the influences of the concealed pollution sources were investigated. When the ventilation system was changed from the air supply type to the air exhaust type, the concentration of formaldehyde increased. The infiltration ratio from concealed space was almost 100% in the case of the beam spaces and the partitions. The ratio from the crawl space under the first floor and the truss space under the roof were not high. The ratio from the envelope wall was changed with the pressure difference. These results showed that it is necessary to prevent infiltration from the concealed space and to control the emission rate from the concealed pollution sources.