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Characterization of an aerosol chamber for human exposures to endotoxin.

Authors
Taylor-L; Parker-CR; Boehlecke-BA; Jacobs-RR
Source
Appl Occup Environ Hyg 2000 Mar; 15(3):303-312
NIOSHTIC No.
20020829
Abstract
The objective of this study was to develop and characterize an exposure chamber in which human subjects could be exposed to low dust concentrations carrying an endotoxin coating. An exposure chamber, dust dispersion method, and endotoxin characterization technique were developed for inhalation exposures. A 6.27 m3 exposure chamber was designed and constructed from cinder block, glass windows, and Plexiglas. Using an acetone adhesion process, Enterobacter agglomerans were adsorbed onto respirable cellulose particles to create the endotoxin aerosol. The size distribution of the endotoxin-treated particles was verified using light microscopy and cascade impactors. A dry powder dust generator was refined to consistently disperse small quantities of the aerosol into the chamber to maintain dust concentrations at approximately 250 mug/m3. Dust levels during the chamber exposures were monitored using a portable continuous aerosol monitor (PCAM). During initial exposure runs, PCAM monitoring stations were positioned at different locations within a 0.5-meter matrix to document mixing patterns. Total dust and cascade impactor samples were collected throughout each exposure period to characterize the chamber operating system and insure the mean airborne dust concentration fulfilled target levels. A one-factor analysis of variance at the 95 percent confidence interval illustrated that there was not a statistically significant difference in the mean dust concentration throughout the exposure runs compared to the individual runs. Together the consistency of the total dust filters, endotoxin concentrations, and aerosol-monitoring instrument were adequate to allow use of the chamber for experimental studies involving human volunteers.
Keywords
Endotoxins; Exposure-chambers; Aerosols; Aerosol-particles; Dusts; Dust-particles; Dust-exposure; Inhalation-studies; Microscopy; Monitors; Monitoring-systems
CODEN
AOEHE9
Publication Date
20000301
Document Type
Journal Article
Fiscal Year
2000
NTIS Accession No.
NTIS Price
Issue of Publication
3
ISSN
1047-322X
NIOSH Division
DSHEFS
Source Name
Applied Occupational and Environmental Hygiene
State
OH
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