A children's day care centre in Finland was the site of a study on the effect of ventilation and air filtration systems on indoor air quality. Indoor and outdoor concentrations of NO, NO2, TSP and PM10 were measured using automatic nitrogen oxide analysers and dust monitoring. Nitrogen oxides and particulate matter from traffic penetrated easily in the absence of filters.50%-70% of nitrogen oxides were excluded with chemical filtration. At holidays and weekends, the particle levels fell less than 10% of the outdoor level, rising to 25% on weekdays.
Mathematical models have been used by various researchers to provide both a fundamental understanding of indoor air quality dynamics and a platform for estimation of IAQ constituents in lieu of experimental measurements. Due to the diverse nature of these applications the complexity and hence applicability and accuracy of the models varies tremendously. Some models have been specifically developed for evaluation of the impact of a broad range of environmental conditions on IAQ constituents.
The primary objective of this study was to evaluate the effectiveness of different commercially available portable indoor air cleaning technologies in removing dust particulates from the indoor air. Suspended respirable particles are of great concern and often identified as important source of indoor air quality problems. The concentrations of particulate and gaseous pollutants encountered in the indoor environment frequently exceed those found outdoors by factor ranging from 2 to 20.