A new sampling approach for assessing indoor air quality

Continuous sampling has been widely adopted for assessing indoor pollutant level. It is believed that the longer the measurement time, the higher the accuracy and improved error rate of the measured average pollutant concentration can be achieved. This study proposes an alternative sampling scheme in which the average pollutant concentration is obtained from two short sampling periods in two sampling sessions when a building was occupied. Two indoor pollutant concentration databases for a 1-year continuous measurement of carbon dioxide (CO2) and radon concentration in a typical open-plan office building in Hong Kong were used to investigate the probable errors of the proposed scheme regarding the sampling period. The results showed that these errors deviated from a long-term average value and correlated with the required measurement time. At certain confidence levels, the potential reductions in measurement time of the proposed sampling scheme would be up to 30% and 50% for CO2and radon, respectively, as compared with an 8-h continuous one.