Spatial–Temporal Dispersion of Aerosolized Nanoparticles During the Use of Consumer Spray Products and Estimates of Inhalation Exposure

We evaluated the spatial-temporal dispersion of airborne nanomaterials during the use of spray consumer products and estimated the level of consumer inhalation exposure. A total of eight spray products including five propellant and three pump types were selected to evaluate the dispersion of airborne nanoparticles across time and space in a cleanroom which could control the background particles. Four products were advertised to contain silver and one contained titanium nanoparticles, while three products were specified no ENM but as being manufactured through the use of nanotechnology. We used direct-reading instruments with a thermodesorber unit to measure the particles (number, mass, surface area), as well as filter sampling to examine physicochemical characteristics. Sampling was conducted simultaneously at each location (1 m, near-field; 2, 3 m, far-field) by distance from the source. We estimated the inhaled doses at the breathing zone, and the doses deposited in each part of the respiratory tract using the experimental data and mathematical models. Nanoparticles released from the propellant sprays persisted in the air and dispersed over a large distance due to their small size (1466-5565 particles/cm 3 ). Conversely, the pump sprays produced larger droplets that settled out of the air relatively close to the source, so the concentration was similar to background level (<200 particles/cm 3 ). The estimates of inhalation exposure also suggested that exposure to nanoparticles was greater with propellant sprays (1.2 × 10 8 ± 4.0 × 10 7 particles/kgbw/day) than pump sprays (2.7 × 10 7 ± 6.5 × 10 6 particles/kgbw/day). We concluded that the propellant sprays create a higher risk of exposure than the pump sprays.