On the basis of the measurement results of airborne radionuclide concentrations in the Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency, the committed effective dose to adults and the committed equivalent dose to thyroid of infants by inhalation were estimated for various indoor and outdoor exposure scenarios. It was demonstrated that the indoor to outdoor airborne radionuclide concentration ratio had a dominant effect on the dose estimate. The committed effective dose to adults was estimated to 0.098 mSv, and the committed equivalent dose to thyroid of infants was 1.8 mSv. These doses were about 1/6 and about 1/9, respectively, compared to the provisional ones with such assumptions as continuous outdoor stay.