Occupational nanoparticle exposure

There is an increased concern that due to the emergence and proliferation of nanotechnology manufacturing, workers in this industry may be exposed to nanoparticles through inhalation. This dissertation helps to address these concerns by evaluating nanoparticle aerosol generation methods for toxicological animal exposure studies; developing methods for estimating particle counts in the nanometer size range using instruments accessible to health and safety personnel, and evaluating the effectiveness of respirators for preventing inhalation exposure to nanoparticles.;The ability of a variety of dry dispersion and wet aerosolization techniques to produce an acceptable nanoparticle aerosol from the bulk powder form for use in a small, whole-body, exposure chamber was evaluated. The nebulizer appears to be the best nanoparticle aerosolization technique tested even though it did not satisfy all of the criteria of producing an acceptable aerosol.;Methods were evaluated for determining if an OPC and CPC can accurately measure counts of engineered nanoparticle aerosols with diameters smaller than 300 nm and acceptably estimate counts of particles with diameters smaller than 100 nm. The effect of physical and chemical properties of aerosol particles on OPC measurement was evaluated and it was observed that the sizing of particles by the OPC is influenced by the refractive index or shape of the particle and accounts for some of the percent error observed in calculating counts. Overall most of the methods overestimated counts which is good in regards to occupational exposure because it errs on the side of caution.;The filtration efficiency of N95 respirators and P100 cartridges against a variety of engineered nanoparticle aerosols in comparison to sodium chloride aerosol was tested. It was observed that average penetrations for all aerosols which challenged N95 respirators were not statistically different from each other. However, for the P100 cartridge the SWCNT aerosol percent penetration was statistically different from NaCl and the other engineered nanoparticles. The most penetrating particle size (MPPS) range of all the test aerosols for the N95 respirator was between 35 nm to 50 nm and for the P100 cartridge was between 100 nm to 200 nm.