Nanoparticles-containing spray can aerosol: characterization, exposure assessment, and generator design.
Chen-BT; Afshari-A; Stone-S; Jackson-M; Schwegler-Berry-D; Frazer-DG; Castranova-V; Thomas-TA
Inhal Toxicol 2010 Nov; 22(13):1072-1082
This is the first report demonstrating that a commercially available household consumer product produces nanoparticles in a respirable range. This report describes a method developed to characterize nanoparticles that were produced under typical exposure conditions when using a consumer spray product. A well-controlled indoor environment was simulated for conducting spray applications approximating a human exposure scenario. Results indicated that, while aerosol droplets were large with a count median diameter of 22 mu m during spraying, the final aerosol contained primarily solid TiO2 particles with a diameter of 75 nm. This size reduction was due to the surface deposition of the droplets and the rapid evaporation of the aerosol propellant. In the breathing zone, the aerosol, containing primarily individual particles (> 90%), had a mass concentration of 3.4 mg/m3, or 1.6 x 10(5) particles/cm3, with a nanoparticle fraction limited to 170 mu g/m3, or 1.2 x 10(5) particles/cm3. The results were used to estimate the pulmonary dose in an average human (0.075 mu g TiO2 per m2 alveolar epithelium per minute) and rat (0.03 mu g TiO2) and, consequently, this information was used to design an inhalation exposure system. The system consisted of a computer-controlled solenoid ''finger'' for generating constant concentrations of spray can aerosols inside a chamber. Test results demonstrated great similarity between the solenoid ''finger''-dispersed aerosol compared to human-generated aerosol. Future investigations will include an inhalation study to obtain information on dose-response relationships in rats and to use it to establish a No Effect Exposure Level for setting guidelines for this consumer product.
Aerosol-particles; Aerosols; Aerosol-sampling; Analytical-processes; Inhalation-studies; Laboratory-testing; Nanotechnology; Particulate-dust; Particulates; Particulate-sampling-methods; Risk-analysis; Statistical-analysis
Bean T.Chen, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, 1095 Willowdale Road, Morgantown, WV 26505, USA