The YoonNelson
model is a descriptive model that uses experimental data to calculate parameters that are
then entered into the model.
 Yoon, Y.H., J.H. Nelson,
Breakthrough Time and Adsorption Capacity of Respirator Cartridges, American Industrial
Hygiene Association Journal, 53:303316 (1992).
 The basic
equation for the model is:



t = breakthrough time (min)
t =
50% contaminant breakthrough time (min)
k' = rate constant (min1)
P = probability of
contaminant breakthrough. 
 The value of t is determined from experimental
data.


The value of k' has been shown to be
related to t by the following
formula:



k = proportionality constant that is constant
independent of concentration and varies only slightly with humidity. 
 The value of t is related to the contaminant concentration by
the equation:



K", a = constants
that can be derived from
experimental data. They vary with humidity, but for humidities £ 50% they are essentially constant.
C_{I} = contaminant assault
concentration. (ppm)

 It is possible to determine the constants k, K", and a from a minimum of 3 experimental
data points. However, the inclusion of additional data points increases the accuracy of
the model.



