Conventional sampling of bioaerosols into liquid impingers can only be perf
ormed with water or another low-viscosity liquid as the collection medium.
Since these liquids evaporate quickly, sampling is generally limited to sho
rt-time periods of 15-30 min. In this study, our recently developed "BioSam
pler", has been used with a non-evaporating, higher viscosity liquid that d
oes not kill nor grow microorganisms, and thus has been used to sample airb
orne bacteria and fungi for several hours. In side-by-side comparisons with
the conventional AGI-30 impinger, sampling indoor air environments over sh
ort-time periods, the BioSampler yielded equivalent or higher culturable co
unts for bacteria and fungi than the AGI-30 when both samplers were operate
d for 30 min with 20 ml of phosphate buffer as the collection medium. The b
io-efficiency of the AGI-30 decreased rapidly with sampling time until the
liquid had evaporated after about 1 1/2 h. When the BioSampler was operated
for 4 h with non-evaporating heavy white mineral oil, the collection effic
iency decreased only moderately due to minimal reaerosolization of collecte
d particles and gentle collection of the viable microorganisms. Samples obt
ained through long-term sampling with the BioSampler may detect culturable
bacteria and fungi at lower ambient concentration levels than is possible t
hrough conventional liquid impingement sampling over short-time periods. (C
) 1999 Elsevier Science Ltd. All rights reserved.