A two-stage cyclone using microcentrifuge tubes for personal bioaerosol sampling

Abstract

Personal aerosol samplers are widely used to monitor human exposure to airborne materials. For bioaerosols, interest is growing in analyzing samples using molecular and immunological techniques. This paper presents a personal sampler that uses a two-stage cyclone to collect bioaerosols into disposable 1.5 ml Eppendorf-type microcentrifuge tubes. Samples can be processed in the tubes for polymerase chain reaction (PCR) or immunoassays, and the use of multiple stages fractionates aerosol particles by aerodynamic diameter. The sampler was tested using fluorescent microspheres and aerosolized fungal spores. The sampler had first and second stage cut-off diameters of 2.6 microm and 1.6 microm at 2 l min(-1)(geometric standard deviation, GSD = 1.45 and 1.75), and 1.8 microm and 1 microm at 3.5 l min(-1)(GSD = 1.42 and 1.55). The sampler aspiration efficiency was >or=98% at both flow rates for particles with aerodynamic diameters of 3.1 microm or less. For 6.2 microm particles, the aspiration efficiency was 89% at 2 l min(-1) and 96% at 3.5 l min(-1). At 3.5 l min(-1), the sampler collected 92% of aerosolized Aspergillus versicolor and Penicillium chrysogenum spores inside the two microcentrifuge tubes, with less than 0.4% of the spores collecting on the back-up filter. The design and techniques given here are suitable for personal bioaerosol sampling, and could also be adapted to design larger aerosol samplers for longer-term atmospheric and indoor air quality sampling.

Characterization of Bioaerosols from Dairy Barns: Reconstructing the Puzzle of Occupational Respiratory Diseases by Using Molecular Approaches

“…These results are not surprising considering the fact that the majority of the particles captured had an aerodynamic diameter of 2.1 m (Fig. 3), which is in the capture range of all three samplers (1,7,31). Therefore, even while using different particulate trapping systems, data were similar, so results from different studies can be compared.…”

“…Airborne dust was sampled at one site each from 13 Holstein dairy barns (eastern Quebec, Canada). Three different air samplers were used, namely, the Institute of Occupational Medicine cassettes (SKC, Ancaster, ON, Canada) or IOM samplers, loaded with 25-mm-diameter gelatin membranes (SKC) and plugged into a Giliar-5 pump (Levitt-Sécurité Limitée, Dorval, QC, Canada), at 2 liters/min (50% cutoff size of 4.0 m); the Coriolis (Bertin Technologies, Montigny-le-Bretonneux, France), which collects 100% of the particles of 4.4 m, at 100 liters/min and loaded with 15 ml of 0.9% saline solution; and the NIOSH two-stage bioaerosol cyclone (BC 251) sampler (31,42), plugged into an AirCon-2 pump (Gilian) and sampling at 10 liters/min for particulate size separation. The size distribution for each stage (50% cutoff size) of the NIOSH sampler was as follows: 2.1 m for the first stage and 0.41 m for the second stage.…”

Indirect Immunodetection of Fungal Fragments by Field Emission Scanning Electron Microscopy

“…Other studies that focused on the occurrence of submicronic fragments in mold-contaminated indoor or outdoor air used methods to detect ␤-glucan (14,16,18,47) and NAHA (21) as biomarkers of fungal fragments in size-fractionated samples. However, these studies were limited by the imprecise fractionation of particles due to confounding variables such as spore bounce (18,47,48). Further, these studies could not predict the number of submicronic fragments present in the air.…”

Physical performances and kinetics of evaporation of the CIP 10-M personal sampler's rotating cup containing aqueous or viscous collection fluid

“…For example, the collection efficiency of the CIP 10-M is close to that of the tube in the 2 L/min one-stage cyclone (Chen et al 2004) and of the first tube of the 2 L/ min two-stage cyclone (Lindsley et al 2006), developed by the National Institute for Occupational Safety and Health (NIOSH). Other wet-type personal bioaerosol samplers (tested using water) such as the Frit-Bubbler (Agranovski 2007) and the PAS-4 or PAS-5 (Tolchinsky et al 2011) have better collection efficiencies than the CIP 10-M for particles smaller than around 3 mm, but show comparable collection efficiencies (»100%) for larger particles.…”