- First study is an all-Italian study still in preprint: CO2 levels whilst wearing a face mask go beyond the safety threshold. 40% of subjects with surgical masks inhale CO2 over the threshold. 99% of subjects wearing an FFP2 inhale CO2 over the threshold. The safety threshold is 5000ppm. The CO2 concentration with the surgical masks was measured to be 4965 ± 1047ppm. With FFP2, it was 9396 ± 2254ppm. It gets worse the younger the subject is. Up to 3 times the threshold in children wearing an FFP2, with an average of more than 2 times (12,847 ± 2898 ppm).
- Peer-reviewed study: Carbon dioxide rises beyond acceptable safety levels in children under nose and mouth covering: Results of an experimental measurement study in healthy children.
[T]he lack of negative correlations between mask usage and COVID-19 cases and deaths suggest that the widespread use of masks at a time when an effective intervention was most needed, i.e., during the strong 2020-2021 autumn-winter peak, was not able to reduce COVID-19 transmission. Moreover, the moderate positive correlation between mask usage and deaths in Western Europe also suggests that the universal use of masks may have had harmful unintended consequences.
More than 150 Comparative Studies and Articles on Mask Ineffectiveness and Harms ⋆ Brownstone Institute
— Read on brownstone.org/articles/more-than-150-comparative-studies-and-articles-on-mask-ineffectiveness-and-harms/