B. Trying to estimate the meaning of the results of the calculations on the probability of detection by a static grid of air samplers with a grid constant “a,” one has to consider the effects of the following on the outcome of the study:a. The threshold of detection is a major factor in investigating the possibility of sampling for the detection of illicit activities.In addition, the threshold of detection is very much affected by the background activity at the sampling site, including legitimate activities with the same environmental signatures, and by themethod of analysis (e.g., radioactivity, bulk analysis, single particle analysis).