The International Society for Respiratory Protection

pdf Vol. 38, No. 1, 2021 pp. 16 - 25 Kavouras (open access)

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JISRP_38_1_2021_Kavouras.pdf

The Effect of Particle Size, Membrane Type, and Face Velocity on TiO2-Containing Paint Dust Filtration

Adam W. Nored, Marie-Cecile G. Chalbot, Jin Y. Shin and Ilias G. Kavouras

Interdisciplinary Engineering Program, School of Engineering, University of Alabama at Birmingham, Birmingham, 1075 13th St S, Birmingham, AL 35205, USA

Department of Environmental Health Sciences, Ryals School of Public Health, University of Alabama at Birmingham, 1665 University Blvd, Birmingham, AL 35233, USA

Department of Biological Sciences, School of Arts and Sciences, New York City College of Technology, 300 Jay St, Brooklyn, NY 11201, USA

Department of Chemical and Environmental Sciences, School of Science, Health and Technology, CUNY Medgar Evers College 1638 Bedford Ave., Brooklyn, NY, 11225, USA

Department of Environmental, Occupational and Geospatial Health Sciences, CUNY Graduate School of Public Health and Health Policy, 55 W 125th Street, New York, NY 10024, USA

The U.S. Centers of Diseases Control suggests the use filtering facepiece respirators (FFRs) for painters and related construction occupations. Engineered titanium dioxide (TiO2) nanoparticles, shown to be more tumorigenic than bulk TiO2, are prevalent in paint formulations. Specific occupational protection protocols are developed to manage tasks associated with TiO2-containing paints and dust. In this study, the efficacy of different types of filtration membranes, namely, packed polypropylene (used in N95 FFRs), cellulose acetate, polycarbonate and polytetrafluoroethylene to remove paint dust containing TiO2 nanoparticles was examined at various conditions. The particle mass size distribution of paint dust was measured using real-time 10-stage Quartz Crystal Microbalance (QCM) cascade impactor. Particles above 300 nm were more efficiently removed by cellulose acetate and polytetrafluoroethylene membranes. The filtration efficiency dropped rapidly for smaller particles in the 100-300 nm range. The results showed that the filtration efficiency of packed polypropylene membrane increased as particle size decreased with the highest computed for particles below 100 nm. This may be due diffusion by Brownian motion and electrostatic attraction. The low collection efficiency of cellulose acetate for the most penetrating and harmful particles below 100 nm was improved by increasing the face velocity. These results can be used by manufacturers to select materials for their respirators. The results can also facilitate future studies on the design and optimization of respirators using polypropylene or cellulose acetate membranes to remove the most potent TiO2-containing ultrafine paint dust particles.

Keywords: Engineered TiO2 nanoparticles, paint dust, ultrafine particles, N95 membrane, cellulose acetate