Nanotechnology Project

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Environment, Health and Safety Research

Filter Efficiency of Typical Respirator Filters for Nanoscale Particles

Project Information

Principal InvestigatorDavid Pui
InstitutionUniversity of Minnesota
Project URLView
Relevance to ImplicationsHigh
Class of NanomaterialGeneric
Impact SectorHuman Health
Broad Research Categories Exposure
NNI identifier

Funding Information

Anticipated Total Fundingn/a
Annual Fundingn/a
Funding SourceNIOSH
Funding MechanismIntramural
Funding SectorGovernment
Start Year2005
Anticipated End Year2006


Manufactured nanoparticles may exist as separate particles of only a few nanometers. Respirator theory predicts that as particle size decreases from 300 nm, diffusion becomes increasingly effective in capturing the particles on the filter filters. However, a recent study suggests that as particles reach sizes of a few nanometers, capture efficiency begins to decline. The goals of this project are to determine (1) whether single-fiber filtration theory is valid for engineered nanoparticles, (2) the possible boundaries of the most penetrating particle size range, and (3) the filtration boundaries of nanosized particles in the diffusional capture mechanism range. The findings from this study will enable the extension of single fiber theory beyond the traditionally described particle range. These findings will also allow NIOSH to make recommendations regarding the effectiveness of respirator filter media for engineered nanoparticles on the basis of experimental data.