To reduce the concentration after occupancy, the mitigation techniques by ventilation or air cleaning are effective. This paper reports the concentration reduction effects of the measures such as continuous mechanical ventilation, the passive product for removing gaseous HCHO and air cleaners for pollutants from the full-scale tests in the newly constructed multi-family residential building. The results are following; 1. The mechanical ventilation was most effective. 2. The sheet-form passive products were effective in the storage, besides the particulate products scarcely affect. 3. The operation of an air cleaner had a little influence on HCHO concentration in the room.
