Atmospheric Environment 36 (2002) 889–898 Development and evaluation of a new personal sampler for culturable airborne microorganisms Igor E. Agranovski a, *, Victoria Agranovski b , Tiina Reponen c , Klaus Willeke c , Sergey A. Grinshpun c a FacultyofEnvironmentalSciences,GriffithUniversity,Brisbane,QLD4111,Australia b CentreforMedical,HealthandEnvironmentalPhysics,QueenslandUniversityofTechnology,Brisbane,QLD,Australia c CenterforHealth-RelatedAerosolStudies,DepartmentofEnvironmentalHealth,UniversityofCincinnati, Cincinnati,OH45267-0056,USA Received 2 April 2001; received in revised form 29 August 2001; accepted 17 September 2001 Abstract The objective of this study was to develop a new personal sampler for viable airborne microorganisms and to evaluate its performance under controlled laboratory conditions and in a field. In the sampler, air is bubbled through a porous medium submerged in a liquid layer, as has earlier been demonstrated to be highly efficient for air purification. The prototype had the physical collection efficiency >95% for particles >0.32 mm in aerodynamic diameter during 8 h of continuous operation. The pressure drop across the sampler was below 1700 Pa, much lower than that of most conventional bioaerosol samplers. The collection liquid losses due to evaporation and aerosolization did not exceed 18% in 8 h and the culturability of sampled microorganisms remained high: the recovery rate of stress-sensitive gram- negative P.fluorescens bacteria was 61720%; for stress-resistant B.subtilis bacteria and A. versicolor fungal spores it was 9579% and 9776%, respectively. Six identical personal samplers were tested simultaneously on a simplified human manikin in an office environment. The culturable microbial concentration data obtained during 2, 4 and 8-h sampling were not affected by the sampling time. Inter-sample variation did not exceed 30%. The laboratory and field evaluations have demonstrated that the new sampler is capable of long-term personal sampling of airborne culturable microorganisms. The estimation of the detection limits has indicated that the sampler is capable of monitoring microbial exposure in the environments with the bacterial concentrations above 15 CFU/m 3 and fungal concentrations above 5 CFU/m 3 when using a sampling time of 8 h. r 2002 Elsevier Science Ltd. All rights reserved. Keywords: Bioaerosol; Personal sampling; Viable microorganisms; Liquid collection; Collection efficiency 1. Introduction Bioaerosols in occupational and residential environ- ments are generally complex mixtures that may include microorganisms (viable and dead) as well as their fragments (e.g., cell wall fragments and flagella) and metabolites (e.g., mycotoxins and volatile organic compounds). They are known to cause various health effects, including infections (e.g., acute viral infection, legionellosis, or tuberculosis), hypersensitivity (allergy; e.g., allergic rhinitis, asthma, or hypersensitivity pneu- monitis), toxic reactions (e.g., humidifier fever), irrita- tions (e.g., sore throat), and inflammatory responses (e.g., sinusitis or conjunctivitis) (Crook and Olenchock, 1995; Burge, 1995b; Macher, 1999). The infectious effects can be caused only by viable pathogen or opportunistic pathogens (viruses, bacteria, and fungi) and, thus, an exposure to infectious microorganisms and the related health risk are determined by their *Corresponding author. Tel.: +617-3875-7923; fax: +617- 3875-7459. E-mail address: i.agranovski@mailbox.gu.edu.au (I.E. Agranovski). 1352-2310/02/$-see front matter r 2002 Elsevier Science Ltd. All rights reserved. PII:S1352-2310(01)00488-5