Indoor bioaerosol dynamics

Nazaroff, William W

Some important observations should be made about equation (1). First, the symbol '~' is used instead of an equal sign because the expression is only approximately true. Among the considerations that limit its strict applicability are that some of the parameters on the right-hand side are time dependent. If applied over short time intervals, one must also be concerned that accumulation, that is, the increase or decrease in the amount of bioaerosol in the indoor space, is not incorporated in equation (1). Also, on a time-averaged basis, the equation is only approximately correct because it does not account for the possibility that time-varying parameters may correlate in such a way that the average of the product is not the same as the product of the averages. A second key point is that some of the processes exhibit strong dependence on particle size. This aspect is addressed in detail in subsequent sections of the study. A third feature of this equation is that it implicitly assumes that the indoor space can be represented as well mixed. That is not always the case. Finally, the equation is specific to the particular schematic representation of the indoor environment depicted in Figure 6a . This configuration accommodates some common conditions in residences, such as air exchange by a combination of natural ventilation