Presents a mathematical model of the formaldehyde concentrations in rooms containing particle boards with known emission rates of formaldehyde. Tests the model in 3 rooms in a new house. Finds agreement within +-15% between calculated and measured formaldehyde concentrations in the rooms before painting and without furniture, carpets etc. Concludes that the combined mathematical model and the analytical method may be suitable for the classification of particle boards according to their emission of formaldehyde and for predictions of formaldehyde concentrations in the indoor environment. The final recommendation however, must await the setting of test conditions, as discussed in the paper.