Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

NIOSHTIC-2 Publications Search

Search Results

Investigation of cut-off sizes and collection efficiencies of portable microbial samplers.

Authors
Yao-M; Mainelis-G
Source
Aerosol Sci Tech 2006 Aug; 40(8):595-606
NIOSHTIC No.
20044414
Abstract
This research investigated the physical collection efficiencies and cut-off sizes of SMA MicroPortable, BioCulture, Microflow, Microbiological Air Sampler (MAS-100), Millipore Air Tester (MAT), SAS Super 180, and RCS High Flow portable microbial samplers when collecting Polystyrene Latex particles ranging from 0.5 to 9.8 um in aerodynamic size. Traditional collection efficiency measurements often directly compare particle concentrations upstream and downstream of the sampler without considering the particle losses. Here, we developed a new approach which tests collection efficiencies of the sampler with and without agar collection plate loaded. This method thus allows estimating the effective collection efficiency, i.e., the fraction of incoming particles deposited onto the agar collection medium only. The experimental cut-off sizes, or d50, of the investigated samplers ranged from 1.2 um for the RCS High Flow, 1.7 um for the MAS-100, 2.1 um for SAS Super 180, to 2.3 um forMAT; for other three samplers they were close to or above 5 um. In most cases the theoretical d50 was lower than the experimental value, which was likely due to the dissipation of impactor jets and the influence of cross-flow in the multi-nozzle impactors. For most samplers, we observed a notable difference between the collection efficiency obtained by the traditional measurement method and the effective collection efficiency. In general, all samplers collected 10% or less of 0.5 um particles onto the agar medium. This study indicates that the use of most of the tested bioaerosol samplers may result in a substantial underestimation of bacterial concentrations, especially of single bacterial cells with diameter 0.5-1.0 um. On the other hand, most of the investigated samplers would be more efficient when collecting larger fungal spores.
Keywords
Microbial-test-systems; Microbiology; Airborne-particles; Inhalation-studies; Air-contamination; Air-quality; Air-samples; Air-sampling-equipment; Air-sampling; Bacteria; Particulate-dust; Particulate-sampling-methods; Particle-aerodynamics; Sampling-methods; Sampling; Exposure-assessment; Exposure-methods; Fungi; Analytical-processes
CODEN
ASTYDQ
Publication Date
20060801
Document Type
Journal Article
Email Address
mainelis@envsci.rutgers.edu
Funding Type
Grant
Fiscal Year
2006
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-K01-OH-008029
Issue of Publication
8
ISSN
0278-6826
Source Name
Aerosol Science and Technology
State
NJ
Performing Organization
Rutgers, The State University of New Jersey, New Brunswick
TOP