Here is updated information from the CDC on Face Coverings.
Evidence for Effectiveness of Masks
Your mask helps protect those around you.
COVID-19 spreads mainly from person to person through respiratory droplets. Respiratory droplets travel into the air when you cough, sneeze, talk, shout, or sing. These droplets can then land in the mouths or noses of people who are near you or they may breathe these droplets in.
Masks are a simple barrier to help prevent your respiratory droplets from reaching others. Studies show that masks reduce the spray of droplets when worn over the nose and mouth.
You should wear a mask, even if you do not feel sick. This is because several studies have found that people with COVID-19 who never develop symptoms (asymptomatic) and those who are not yet showing symptoms (pre-symptomatic) can still spread the virus to other people. Wearing a mask helps protect those around you, in case you are infected, but not showing symptoms.
It is especially important to wear a mask when you are indoors with people you do not live with and when you are unable to stay at least 6 feet apart since COVID-19 spreads mainly among people who are in close contact with one another.
Mask adaptations and alternatives
CDC recognizes that wearing masks may not be possible in every situation or for some people. Those who cannot wear a mask are urged to prioritize virtual engagement when possible. For in-person activities, we have provided a few examples of what you can do to make wearing a mask more feasible and how to reduce the spread of COVID-19, if you cannot wear a mask.
Situations where wearing a mask may not be possible
- Make sure to maintain physical distance from others when you cannot wear a mask.
CDC recommends wearing a mask while dining in a restaurant, particularly indoors and when speaking with restaurant workers and servers, except when actively eating or drinking. The risk of COVID-19 spread increases in a restaurant or bar setting as interactions within 6 feet of others increase. Masks may reduce the risk of COVID-19 spread when worn in any of these risk scenarios.
- Do not wear a mask when doing activities that may get your mask wet, like swimming at the beach or pool. A wet mask can make it difficult to breathe and may not work as well when wet.
High intensity activities
- Masks should always be used in public settings, but if you are unable to wear a mask because of difficulty breathing during high intensity activities, choose a location with greater ventilation and air exchange (for instance, outdoors versus indoors) and where you can keep at least 6 feet of distance from others during the activity. If such a location is not available, opt for low-intensity activities such as walking or yoga that allow for mask wearing.
- If you are able to wear a mask, remove your mask if it gets moist from sweat and replace it with a clean mask.
- Opt for an activity that does not require using mouth guards or helmets. Wearing a mask with these types of protective equipment is not safe if it makes it hard to breathe.
- Supervise children who are wearing a mask while playing sports.
Mask use and carbon dioxide
Wearing a mask does not raise the carbon dioxide (CO2) level in the air you breathe
A cloth mask does not provide an airtight fit across the face. The CO2 completely escapes into the air through the cloth mask when you breathe out or talk. CO2 molecules are small enough to easily pass through any cloth mask material. In contrast, the respiratory droplets that carry the virus that causes COVID-19 are much larger than CO2, so they cannot pass as easily through a properly designed and properly worn cloth mask.
- In cold weather, masks may become wet from breathing, snow, or other precipitation. Change a mask when it becomes wet. A wet mask is harder to breathe through, is less efficient at preventing your respiratory droplets from reaching others, and allows for more respiratory droplets to escape around the edges of the mask. It is especially important to have one or more replacement masks during cold weather. If your reusable mask becomes wet, put it in a sealed plastic bag until you can wash it.
- Scarves and other headwear such as ski masks and balaclavas used for warmth are usually made of loosely knit fabrics that are not suitable for use as masks to prevent COVID-19 transmission. They can be worn over a mask.
- If you wear glasses, find a mask that fits closely over your nose or has a nose wire to help reduce fogging. Consider using an antifogging spray that is made for eyeglasses.