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Computer-automated silica aerosol generator and animal inhalation exposure system.

Authors
McKinney-W; Chen-B; Schwegler-Berry-D; Frazer-D
Source
Inhal Toxicol 2013 Jul; 25(7):363-372
NIOSHTIC No.
20042828
Abstract
Inhalation exposure systems are necessary tools for determining the dose response relationship of inhaled toxicants under a variety of exposure conditions. The objective of this study was to develop an automated computer controlled system to expose small laboratory animals to precise concentrations of uniformly dispersed airborne silica particles. An acoustical aerosol generator was developed which was capable of re-suspending particles from bulk powder. The aerosolized silica output from the generator was introduced into the throat of a venturi tube. The turbulent high-velocity air stream within the venturi tube increased the dispersion of the re-suspended powder. That aerosol was then used to expose small laboratory animals to constant aerosol concentrations, up to 20 mg/m3, for durations lasting up to 8 h. Particle distribution and morphology of the silica aerosol delivered to the exposure chamber were characterized to verify that a fully dispersed and respirable aerosol was being produced. The inhalation exposure system utilized a combination of airflow controllers, particle monitors, data acquisition devices and custom software with automatic feedback control to achieve constant and repeatable exposure environments. The automatic control algorithm was capable of maintaining median aerosol concentrations to within +/- 0.2 mg/m3 of a user selected target concentration during exposures lasting from 2 to 8 h. The system was able to reach 95% of the desired target value in 510 min during the beginning phase of an exposure. This exposure system provided a highly automated tool for conducting inhalation toxicology studies involving silica particles.
Keywords
Inhalation-studies; Aerosol-generators; Aerosols; Aerosol-particles; Silica-dusts; Exposure-methods; Computer-models; Computer-software; Exposure-assessment; Control-systems; Controlled-environment; Laboratory-animals; Laboratory-techniques; Airborne-particles; Dispersion; Exposure-levels; Exposure-chambers; Acoustical-materials; Particle-accelerators; Particle-aerodynamics; Morphology; Respirable-dust; Feedback-controls; Air-flow; Air-monitoring; Toxic-materials; Toxins; Analytical-instruments; Author Keywords: Aerosol; automated; exposure system; inhalation; silica
Contact
Walter McKinney, CDC/NIOSH, 1095 Willowdale Road, Morgantown, WV 26505, USA
CODEN
INHTE5
CAS No.
14808-60-7; 7631-86-9
Publication Date
20130701
Document Type
Journal Article
Email Address
wdm9@cdc.gov
Fiscal Year
2013
NTIS Accession No.
NTIS Price
Identifying No.
B20130718
Issue of Publication
7
ISSN
0895-8378
NIOSH Division
HELD
Priority Area
Manufacturing
Source Name
Inhalation Toxicology
State
WV
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