While medical 𝗡𝟵𝟱 𝗺𝗮𝘀𝗸𝘀 are the most effective, these as well as medical surgical masks should be allocated to those in clinical and healthcare settings only.

𝗛𝘆𝗯𝗿𝗶𝗱 𝗺𝗮𝘀𝗸𝘀 – 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.

𝗧𝘄𝗼 𝗹𝗮𝘆𝗲𝗿𝘀 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 𝗡𝗢𝗧 𝗲𝗳𝗳𝗲𝗰𝘁𝗶𝘃𝗲:

1- 𝗦𝗰𝗮𝗿𝘃𝗲𝘀, 𝗯𝗮𝗻𝗱𝗮𝗻𝗮𝘀: 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- 𝗩𝗲𝗻𝘁𝗶𝗹𝗮𝘁𝗲𝗱 𝗺𝗮𝘀𝗸𝘀: 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- 𝗡𝗲𝗰𝗸 𝗴𝗮𝗶𝘁𝗲𝗿𝘀: These unfortunately seem to convert large particles into smaller droplets, using this is actually worse than not having a mask on!

4- 𝗣𝗹𝗮𝘀𝘁𝗶𝗰 𝗺𝗼𝘂𝘁𝗵 𝗴𝘂𝗮𝗿𝗱𝘀/𝘀𝗵𝗶𝗲𝗹𝗱𝘀: 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.

𝗪𝗵𝗲𝗿𝗲 𝘄𝗲 𝗹𝗮𝗰𝗸 𝗶𝗻𝗳𝗼𝗿𝗺𝗮𝘁𝗶𝗼𝗻:

𝗙𝗮𝗰𝗲 𝘀𝗵𝗶𝗲𝗹𝗱𝘀: 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 𝗯𝗼𝘁𝗵 𝗺𝗮𝘀𝗸 𝗮𝗻𝗱 𝗳𝗮𝗰𝗲 𝘀𝗵𝗶𝗲𝗹𝗱. In these situations, face shields protect against direct forceful expulsion of large particles, and are especially useful in protecting eyes.

𝗦𝘁𝗮𝘆 𝘀𝗮𝗳𝗲 𝗮𝗻𝗱 𝗺𝗮𝘀𝗸 𝘂𝗽!

Signed,

Unambiguous Science