In the aerobiological sampling methodology, an impinger and a cyclone were used to sample aerosols of airborne organisms. Aerobiological samplers are thus vitally important in the detection of containment breaches in bioprocess plants. For the purpose of this report the term "aerobiological samplers" is used to describe devices which can collect process microorganisms, which can then be counted by various means. Settle plates and impactors rely on airborne organisms settling or impacting onto solid media, while impingers and cyclones impinge organisms into a collection fluid. Microbial adenosine triphosphate (ATP) can be assayed by a bioluminescent reaction. In microbial assays of food and medical samples, nonmicrobial cells must first be treated to release their ATP into solution. Rapid methods of enumeration such as ATP assay and the direct epifluorescent technique may provide a means of detecting and counting the viable but nonculturable cells.