Collection of Airborne Microorganisms into Liquid by Bubbling through Porous Medium
Abstract:A new method for the removal of airborne particles by air bubbling through fibrous filters immersed into a liquid has recently been developed (Agranovski et al. 1999) and shown to be very efficient for cleaning air environments with ultra-fine aerosol particles. The principal objective of the present study was to evaluate the new bubbling technique for the collection of airborne bacteria into a liquid for subsequent physical and microbiological analysis. It was found that the technique is capable of achieving a physical collection efficiency of 98.5% or higher for particles larger than 0.3 m in aerodynamic diameter. The physical collection efficiency of the prototype bubbler remained at that high level for 8 h of continuous operation with negligible variation of the pressure drop across the device. Evaporation of the collection fluid did not exceed 20% during 8 h, and the reaerosolization effect on the physical collection efficiency of the bubbler prototype was <8%. The recovery rate of gram-negative Pseudomonas fluorescens bacteria collected for 20 min was shown to be as high as 74% ± 10%. Its decrease with time was not statistically significant: the recovery rate reached 63% ± 15% and 58% ± 16% after 4 and 8 h of continuous operation, respectively. Thus the bubbling technique was demonstrated to be suitable for collecting viable airborne bacteria even if they are sensitive to the stress.
Document Type: Research Article
Affiliations: 1: Faculty of Environmental Sciences, Griffith University, Brisbane, QLD, Australia 2: Centre for Medical and Health Physics, Queensland University of Technology, Brisbane, QLD, Australia 3: Aerosol Research and Exposure Assessment Laboratory, Department of Environmental Health, University of Cincinnati, Cincinnati, Ohio
Publication date: 2002-04-01