Wearing face masks as a potential source for inhalation and oral uptake of inanimate toxins - A scoping review.

BACKGROUND: From 2020 to 2023 many people around the world were forced to wear masks for large proportions of the day based on mandates and laws. We aimed to study the potential of face masks for the content and release of inanimate toxins. METHODS: A scoping review of 1003 studies was performed (database search in PubMed/MEDLINE, qualitative and quantitative evaluation). RESULTS: 24 studies were included (experimental time 17 min to 15 days) evaluating content and/or release in 631 masks (273 surgical, 228 textile and 130 N95 masks). Most studies (63%) showed alarming results with high micro- and nanoplastics (MPs and NPs) release and exceedances could also be evidenced for volatile organic compounds (VOCs), xylene, acrolein, per-/polyfluoroalkyl substances (PFAS), phthalates (including di(2-ethylhexyl)-phthalate, DEHP) and for Pb, Cd, Co, Cu, Sb and TiO2. DISCUSSION: Of course, masks filter larger dirt and plastic particles and fibers from the air we breathe and have specific indications, but according to our data they also carry risks. Depending on the application, a risk-benefit analysis is necessary. CONCLUSION: Undoubtedly, mask mandates during the SARS-CoV-2 pandemic have been generating an additional source of potentially harmful exposition to toxins with health threatening and carcinogenic properties at population level with almost zero distance to the airways.

Carbon dioxide rises beyond acceptable safety levels in children under nose and mouth covering: Results of an experimental measurement study in healthy children.

Nose and mouth covering (NMC) has been made compulsory for children in many countries during the Covid-19 pandemic. We wanted to determine the average CO2 levels in inhaled air with NMC in children between age 6 and 17. We used short term measurements under surgical masks and FFP2 masks according to European norm EN 149, compared to baseline in an experimental, intra-individually controlled study over 25 min. CO2 content was measured every 15 s using an automated dual-wavelength infrared CO2 measurement device (G100, Geotech, Leamington Spa, UK) over 25 min in a short-term experimental setting, with children seated. After baseline measurement children were provided with two types of commonly worn NMC: surgical masks and FFP2--masks in randomized sequence for 3 min each. We kept ambient CO2-levels below 1000 parts per million (ppm) through frequent ventilation. We measured breathing frequency and pulse as potential physiological moderator variables. Forty-five children, 25 boys, 20 girls, with a mean age of 10.7 years (standard deviation 2.6) were measured. We measured 13,100 ppm (SD 380) under surgical mask and 13,900 ppm (SD 370) under FFP2 mask in inhaled air. A linear model with age as a covariate showed a highly significant effect of the condition (p < 1*10-9). We measured 2,700 ppm (SD 100) CO2 at pre-baseline and 2,800 ppm (SD 100) at post-baseline, a non-significant small difference. Appropriate contrasts revealed that the change was due to the masks only and the difference between the two types of masks was small and not significant. Wearing of NMC (surgical masks or FFP2- -masks) raises CO2 content in inhaled air quickly to a very high level in healthy children in a seated resting position that might be hazardous to children's health.

Comparison of primary human fibroblasts and keratinocytes with immortalized cell lines regarding their sensitivity to sodium dodecyl sulfate in a neutral red uptake cytotoxicity assay.

Cell lines present a valuable tool for in vitro assessment of skin damage caused by application of cosmeticals or pharmaceuticals. They form a reproducible test system under controllable test conditions and, in many cases, can be used as alternatives to animal testing in order to assess the compatibility of drugs or cosmetics and human skin. Yet, it can not necessarily be assumed that the behavior of cultured cells, when treated with different substances, is exactly consistent with the behavior of cells being part of a live organism. Becoming immortal, cells exhibit changes in genotype and/or phenotype, possibly resulting in modified reactions to external influences. Therefore, to obtain results close to in vivo studies, it seems apparent to use primary cells for testing that have not yet undergone any modifications. To compare the properties of primary fibroblasts (Normal Human Dermal Fibroblasts, NHDF) and primary keratinocytes (Normal Human Epidermal Keratinocytes, NHEK) with those of immortal cell lines (3T3 (ACC 173) Swiss albino mouse fibroblasts and HaCaT (human, adult, low calcium, high temperature, human adult skin keratinocytes) cells), their sensitivities in cytotoxicity assays have been assessed. While both fibroblast cell cultures showed similar sensitivities towards sodium dodecyl sulfate (SDS), primary keratinocytes died at SDS concentrations about three times lower than the immortal HaCaT cells.