Effects of Size and Morphology of TiO2 and SiO2 Airborne Nanoparticles on their Filtration through Chemical Protective Clothing

Abstract

Titanium dioxide (nTiO2) and silicon dioxide (nSiO2) nanoparticles are employed in numerous products that are used daily and also in building materials such as concrete, plaster or paints. Whether during manufacturing or released by sanding or polishing, nTiO2 and nSiO2 can become airborne, exposing workers to possible health risks. Although the penetration of airborne nanoparticles through the filtering media used in respiratory protective equipment has been studied for several years with different types of airborne nanoparticles, the study of the efficiency of chemical protective clothing (CPC) materials is much more recent. Furthermore, these studies were generally conducted with polydisperse sodium chloride airborne nanoparticles, which are particles that are seldom used in the workplace. The present work focuses on the effect of the size and shape of nTiO2 and nSiO2 airborne nanoparticles on their penetration level through a sample of filtering material directly taken from a model of nonwoven CPC. The clogging effect was also evaluated and its impact on the pressure drop was determined. Results indicate that contrary to the particle size, the shape could have a significant effect on the level of penetration. Moreover, clogging due to the deposit of nanoparticles on the filtering fibers could be seen, in some cases, in terms of penetration, but did not have a significant effect on the pressure drop.