Eveline Verleysen et al.

Although titanium dioxide (TiO2) is a suspected human carcinogen when inhaled, fiber-grade
TiO2 (nano)particles were demonstrated in synthetic textile fibers of face masks intended for the
general public … No assumptions were made about the likelihood of the release of TiO2 particles itself, since direct measurement of release and inhalation uptake when face masks are worn could not be assessed. The importance of wearing face masks against COVID-19 is unquestionable. Even so, these results urge for in depth research of (nano) technology applications in textiles to avoid possible future consequences caused by a poorly regulated use and to implement regulatory standards phasing out or limiting the amount of TiO2 particles, following the safe-by-design principle.