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Development and validation of a simple numerical model for estimating workplace aerosol size distribution evolution through coagulation, settling, and diffusion.

Authors
Maynard-AD; Zimmer-AT
Source
Aerosol Sci Tech 2003 Oct; 37(10):804-817
NIOSHTIC No.
20023608
Abstract
Recent research has indicated that the toxicity of inhaled ultrafine particles may be associated with the size of discrete particles deposited in the lungs. However, it has been speculated that in some occupational settings rapid coagulation will lead to relatively low exposures to discrete ultrafine particles. Investigation of likely occupational exposures to ultrafine particles following the generation of aerosols with complex size distributions is most appropriately addressed using validated numerical models. A numerical model has been developed to estimate the size-distribution time-evolution of compact and fractal-like aerosols within workplaces resulting from coagulation, diffusional deposition, and gravitational settling. Good agreement has been shown with an analytical solution to lognormal aerosol evolution, indicating good compatibility with previously published models. Validation using experimental data shows reasonable agreement when assuming spherical particles and coalescence on coagulation. Assuming the formation of fractal-like particles within a range of diameters led to good agreement between modeled and experimental data. The model appears well suited to estimating the relationship between the size distribution of emitted well-mixed ultrafine aerosols, and the aerosol that is ultimately inhaled where diffusion loses are small.
Keywords
Aerosol-particles; Lung-irritants; Diffusion-analysis; Aerosols; Aerosol-generators; Mathematical-models; Measurement-equipment; Analytical-models; Nanotechnology
Contact
National Institute for Occupational Safety and Health, Division of Applied Research and Technology, 4676 Columbia Parkway, Cincinnati, OH 45226
CODEN
ASTYDQ
Publication Date
20031001
Document Type
Journal Article
Email Address
amaynard@cdc.gov
Fiscal Year
2004
NTIS Accession No.
NTIS Price
Issue of Publication
10
ISSN
0278-6826
NIOSH Division
DART
Priority Area
Research Tools and Approaches: Exposure Assessment Methods
Source Name
Aerosol Science and Technology
State
OH
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