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Thoracic size-selection of fibres: dependence of penetration on fibre length for five thoracic sampler types.

Authors
Maynard-AD
Source
Ann Occup Hyg 2002 Aug; 46(6):511-522
NIOSHTIC No.
20022243
Abstract
It has been suggested that the non-size-selective sampling methods currently used for fibrous aerosols potentially lead to the presence of large compact particles, agglomerates and fibre clumps in samples, which in turn reduce the accuracy and precision of the manual fibre counting techniques employed to analyse samples. The use of thoracic size-selective samplers has been proposed as an alternative, leading to the prevention of large particles reaching the collection substrate while at the same time bringing fibre sampling into line with general occupational aerosol sampling methodologies. Thoracic samplers should give good agreement with current sampling methods under ideal conditions based on aerodynamic fibre properties. However, the effect of fibre length on sampling efficiency is not known. The sampling efficiency of five thoracic samplers was therefore measured as a function of fibre length for respirable fibres between 10 and 60 microm long. These included the commercially available GK2.69 cyclone and the CATHIA sampler, the IOM thoracic sampler, a modified version of the SIMPEDS cyclone and a modified version of the IOM inhalable sampler. Length-monodisperse fibres were generated using a dielectrophoretic fibre classifier and sampler penetration was measured as a function of fibre length. No length-dependent sampling effects were observed for the CATHIA, GK2.69, modified SIMPEDS and modified IOM inhalable samplers for fibres <60 microm. Data for the IOM thoracic sampler showed a significant trend of reducing sampling efficiency for fibres >30 microm. Overall, the laboratory results indicated that the five sampler types are likely to perform as well as or better than the currently used 25 mm cowled sampler in the field.
Keywords
Aerosols; Particulates; Particulate-dust; Dusts; Sampling-methods; Sampling-equipment; Fibrous-dusts
Contact
National Institute of Occupational Safety and Health, Division of Applied Research and Technology, 4676 Columbia Parkway, Cincinnati, OH, 45226
CODEN
AOHYA3
Publication Date
20020801
Document Type
Journal Article
Email Address
amaynard@cdc.gov
Fiscal Year
2002
NTIS Accession No.
NTIS Price
Issue of Publication
6
ISSN
0003-4878
NIOSH Division
DART
Priority Area
Research Tools and Approaches: Exposure Assessment Methods
Source Name
Annals of Occupational Hygiene
State
OH
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