While medical ??? ????? are the most effective, these as well as medical surgical masks should be allocated to those in clinical and healthcare settings only.

?????? ????? – combining two layers of 600-thread count cotton paired with another material such as silk, chiffon or flannel are the next best. These filter 94% of small particles and 96% of larger particles.

??? ?????? of 600-thread count cotton are a close second, filtering out large particles effectively but not as effective in filtering out smaller particles.

What are ??? ?????????:

1- ???????, ????????: use these as a last resort if you are caught off-guard without a mask handy. They filter under 50% of large and small particles.

2- ?????????? ?????: These are masks that have a valve in the front. These masks do not filter air that you exhale, making them ineffective in reducing transmission.

3- ???? ???????: These unfortunately seem to convert large particles into smaller droplets, using this is actually worse than not having a mask on!

4- ??????? ????? ??????/???????: There is simply no point in this, it’s a complete waste of money. They do not protect yourself or others as droplets escape easily from all sides.

????? ?? ???? ???????????:

???? ???????: Not enough data to compare efficacy of wearing just a face shield vs a mask. These likely protect against direct large droplets, but will have no efficacy on smaller suspended in air particles. In airflow visualization studies, face shields were only able to block 68% of small particles. In addition, there exists a few case reports of infections in individuals wearing just a face shield.

Where face shields can help are for a double layer of protection in conjunction with a mask, ie ???? ???? ??? ???? ??????. In these situations, face shields protect against direct forceful expulsion of large particles, and are especially useful in protecting eyes.

???? ???? ??? ???? ??!

Signed,

Unambiguous Science