Masks don't work unless they're sealed, have an air filtration system and you never touch them. Even N95 masks provide very little in the way of protection unless used in a sterile environment:
There have been studies about this from decades ago showing that standard cloth masks don't work to reduce the spread of influenza-type diseases because they don't filter out the particulate matter, especially if they're unsealed:
https://www.tandfonline.com/doi/pdf/10.1080/15459620903120086
Common fabric materials and cloth masks showed a wide variation in penetration values for polydisperse (40–90%) as well as monodisperse aerosol particles in the 20–1000 nm range (40–97%) at 5.5 cm s−1 face velocity. The penetration levels obtained for fabric materials against both polydisperse and monodisperse aerosols were much higher than the value for the control N95 respirator filter media but were in the range found for some surgical masks in previous studies. Penetrations of monodisperse aerosol particles slightly increased at 16.5 cm s−1 face velocity, while polydisperse aerosols showed no significant effect except one fabric mask with an increase. The penetration values obtained for common fabric materials indicate that only marginal respiratory protection can be expected for submicron particles taking into consideration face seal leakage.
Thirty-two health care workers completed the study, resulting in 2464 subject days. There were 2 colds during this time period, 1 in each group. Of the 8 symptoms recorded daily, subjects in the mask group were significantly more likely to experience headache during the study period (P < .05). Subjects living with children were more likely to have high cold severity scores over the course of the study.
Face mask use in health care workers has not been demonstrated to provide benefit in terms of cold symptoms or getting colds. A larger study is needed to definitively establish noninferiority of no mask use.
TL;DR For public use, unless you're wearing a fully sealed mask that you NEVER touch, masks don't work.
Masks don't work unless they're sealed, have an air filtration system and you never touch them. Even N95 masks provide very little in the way of protection unless used in a sterile environment:
There have been studies about this from decades ago showing that standard cloth masks don't work to reduce the spread of influenza-type diseases because they don't filter out the particulate matter, especially if they're unsealed: https://www.tandfonline.com/doi/pdf/10.1080/15459620903120086
Here's the results from one study done back in 2010: https://academic.oup.com/annweh/article/54/7/789/202744
And here's a study specifically related to healthcare professionals wearing masks in Japan: https://pubmed.ncbi.nlm.nih.gov/19216002/
The results...
TL;DR For public use, unless you're wearing a fully sealed mask that you NEVER touch, masks don't work.