THE DANISH TWIN APARTMENT STUDY .2. MATHEMATICAL-MODELING OF THE RELATIVE STRENGTH OF SOURCES OF INDOOR AIR-POLLUTION

This study deals with the modeling of air pollution in apartments from laboratory measurements of source strengths, using formaldehyde and T otal Volatile Organic Compounds (TVOCs) as model pollutants. The sourc es in two test apartments were grouped into two: building-related sour ces and occupant-related sources. The measured source strengths and ve ntilation rates were used for the prediction of concentrations expecte d in the apartments. These predictions were compared to measurements i n the apartment over 12 months. The conclusions were that the model pr edictions based on emission rates measured in the laboratory can be us ed to predict the long-term concentration of the two model pollutants in the apartments. Considering the measured differences in ventilation between the apartments, an occupant emission rate of between 0.2 and 0.3 mg/h/kg body weight could be estimated. Based on previous suggeste d limits of acceptable exposures of humans to VOCs, an acceptable aver age emission rate of VOCs from building materials in general was estim ated to be about 30 mu g/m(2)/h. The modeling showed that during the f irst 200 days, building materials dominated the emissions. After this, sources relating to the occupants dominated. On average about half of the VOC pollution originated from the building materials.