Comparative Testing and Evaluation of Nine Different Air Samplers: End-to-End Sampling Efficiencies as Specific Performance Measurements for Bioaerosol Applications

Abstract

Accurate exposure assessments are needed to evaluate health hazards caused by airborne microorganisms and require air samplers that efficiently capture representative samples. This highlights the need for samplers with well-defined performance characteristics. While generic aerosol performance measurements are fundamental to evaluate/compare samplers, the added complexity caused by the diversity of microorganisms, especially in combination with cultivation-based analysis methods, may render such measurements inadequate to assess suitability for bioaerosols. Specific performance measurements that take into account the end-toend sampling process, targeted bioaerosol and analysis method could help guide selection of air samplers.Nine different samplers (impactors/impingers/cyclones/ electrostatic precipitators/filtration samplers) were subjected to comparative performance testing in this work. Their end-to-end cultivation-based biological sampling efficiencies (BSEs) and PCR-/microscopy-based physical sampling efficiencies (PSEs) relative to a reference sampler (BioSampler) were determined for gram-negative and gram-positive vegetative bacteria, bacterial spores, and viruses.Significant differences were revealed among the samplers and shown to depend on the bioaerosol's stress-sensitivity and particle size. Samplers employing dry collection had lower BSEs for stresssensitive bioaerosols than wet collection methods, while nonfilterbased samplers showed reduced PSEs for 1 μm compared to 4 μm bioaerosols. Several samplers were shown to underestimate bioaerosol concentration levels relative to the BioSampler due to having lower sampling efficiencies, although they generally obtained samples that were more concentrated due to having higher concentration factors.Our work may help increase user awareness about important performance criteria for bioaerosol sampling, which could contribute to methodological harmonization/standardization and result in more reliable exposure assessments for airborne pathogens and other bioaerosols of interest.

Collection efficiency of liquid‐based samplers for fungi in indoor air

“…Thus, the samples of the Coriolis were free of potential cell loss inherent in centrifugation processing. With such advantage, however, the current results of R values (Figure D and D) and GLM analyses clearly indicate that the Coriolis collected fungi significantly less than the BioSampler, in line with previous findings on bacteriophage MS2, Bacillus atrophaeus spores and Serratia marcescens . While both samplers are swirling aerosol collectors with similar collection principle, the collection efficiency differs between samplers.…”

“…Previous studies also illustrated that the Coriolis sampler provides equivalent recovery of fungal spores compared with the Hirst spore trap method . However, to our best knowledge, the CE of the Coriolis and the BioSampler has not been simultaneously assessed for airborne fungi although such information is available for bacteria, viruses, and bacteriophages . Whether the Coriolis is equivalent to the BioSampler in terms of fungal collection efficiency remains unknown.…”

Efficient collection of viable virus aerosol through laminar‐flow, water‐based condensational particle growth

“…It has been used as a refere‐nce sampler for many virus aerosol studies (Woo ; Dybwad et al . ; Fennelly et al . ).…”

Highly efficient collection of infectious pandemic influenza H1N1 virus (2009) through laminar-flow water based condensation

“…Although known to be inefficient in collecting submicrometer-sized aerosols (Hogan et al, 2005), the BioSampler has been used as a reference sampler for many virus aerosol studies (e.g., Lednicky and Loeb [2013] and Dybwad et al [2014]). Additionally, impinger-based collection methods often inactivate viruses, especially "stress-sensitive viruses," reducing the usefulness of data acquired by these methods (Agranovski et al 2005).…”