Research

From PubMed/NIH...

 "For tea towel fabric, studied with aerosol-sized particles, filtration efficiency in experiments using a bacterial marker was 83% with 1 layer and 97% with 2 layers, compared with 96% for a medical mask. In experiments using virus, 1 layer of tea towel had 72% efficiency and 1 layer of T-shirt fabric 51%, compared with 90% for a medical mask. A 2020 study confirms that some fabrics block clinically useful percentages of transmission, even for aerosols and even in single layers; multiple layers improve efficiency." 

 In comparison, an N-95 mask has a filtration efficiency of 95%. This evidence suggests that cloth masks could reduce risk of infection through aerosol more than previously thought .

Testing in a recent study showed that cloth masks are 72 to 89 percent effective at preventing aerosols from escaping the mask. This means a cloth mask would perform well at preventing transmission from the wearer to others.  Another study found that cultures that have traditionally used masks had lower rates of infection. They also predicted that if 80% of the population wore cloth masks it would be three times more effective at reducing the rates of infection than a total lock-down for the duration of the pandemic.

Several studies have shown that CO2 build up N-95 respirators has no negative effects in the average healthy adult, even under moderate exercise. There is no scientific evidence that slightly higher CO2 exposure found in N95 respirators will cause the wearer to faint. Cloth masks have lower rates of filtration and higher rates of gas diffusion, so they cause very little CO2 build-up. All evidence shows that cloth masks cause little to no negative heath effect on a healthy individual. 

Most likely, yes. Twenty six of the fifty states as well as the district of Colombia and Puerto Rico have mandated wearing masks in all public spaces. These restrictions apply in all public places, public transport included. Even in states that do not mandate masks, it is still a good idea to don one.

No, face shields can protect the face from direct aerosols produced by coughs and sneezes, but they will not prevent circulating airborne particles from being inhaled. These particles can remain in the air for up to three hours, circulating underneath the shield into facial cavities.  Face shields also lack the ability to prevent the wearer from infecting others. The optimal way to use face-shields is in conjunction with a mask.

To put on a mask, grab by the strings and place behind ears. Masks should fit tightly from below the chin up to the bridge of the nose. Do not ever touch the front of the mask. The side of the mask that is in contact with the face should never be in contact with any potentially contaminated surface.  For more guidelines go to the CDC  website