Abstract
Ministry of Land, Infrastructure and Transport provides "Ventilation for 30 minutes" and "Seal up for 5 hours or more" before it begins to sample the air. However, a simpler procedure is hoped for on the business. Then, we showed the following three kinds of simplification method. 1. shortening or omission of "Ventilation for 30 minutes" 2. Change in passive sampler installation time 3. Conversion of concentration measured at shortened sealing up time Afterwards, we confirmed the effectiveness of these methods with measurement of the contaminant concentration in the room under sealing up.