Rudnick S.B., Milton D.K.
Bibliographic info:
Indoor air, 3/2003, Vol. 13, No. 3, pp 237-245, 2 Fig., 1 Tab., 24 Ref.

Accurate mathematical models of airborne infection are needed to estimate the risk from secondary transmission of biological warfare agents. An equation has been derived by the authors : they determined the fraction of inhaled air that has been exhaled previously by someone in the building by using a CO2 concentration as a marker for exhaled-breath exposure.
There is a critical rebreathed fraction of indoor air below which airborne propagation of common respiratory infections and influenza will not occur.