Indoor bioaerosol dynamics

Nazaroff, William W

The air exchange rate (AER) is an important metric for characterizing air quality aspects of buildings. This measure is the volume-normalized flow rate of air from the building to outdoors. As depicted in Figure 6 , the AER would be (Q N +Q L )/V for the residential sche- matic (i) and (Q M +Q L )/V for the commercial schematic (ii). Figure 8 presents a summary of AER data from two large studies conducted in the United States. The measurements in residences ( Figure 8a) show a median in the approximate range of 0.5-1 per hour. Considering individual households, most of the data lie within a range that spans about an order of magnitude, from 0.2 to 3 per hour. The BASE study of~100 commercial buildings (Figure 8b) shows a similar central tendency and a somewhat larger range, especially at the high end of the distribution. Each of these data sets conforms reasonably well to a lognormal distribution.