Fig. 5.

Average total CFU normalized to sampler’s horizontal surface area (CFU/cm², mean ± 1SD) of culturable bacteria (a) and culturable fungi (b) collected by passive samplers. For REPS, projected surface area was used (380 mm², bottom of sampler has a 22 mm diameter). The number of samples presented here by sampler are: agar settling plates (n=30 per campaign per microbe type), passive PTFE filter (n=6 per campaign per microbe type), REPS (n=6 per campaign per microbe type). Agar settling plates were deployed daily for four hours in triplicate for bacteria and fungi. Campaign total was determined as the sum of averaged daily enumerated CFU multiplied by six to scale up to continuous 24-hour sampling. For the passive samplers, agar spread plates were made at the end of each campaign for the two out of six REPS and the two out of six passive PTFE filters with the highest number of stained bacteria + fungi as determined by microscopy.