What kind of mask should you wear?
Source: VietFactCheck
With the higher infectiousness of the COVID-19 Omicron variant, it is important to wear a mask that will protect you and your loved ones from the virus. The American Conference of Governmental Industrial Hygienists (ACGIH) recently studied which masks are most effective against COVID-19.
The table below shows which masks offer the most protection against COVID-19. If the COVID-19 infected person is not wearing a mask, it would take only 15 minutes for an infectious amount of COVID-19 to be transmitted to another person also not wearing a mask. If both people are wearing cloth masks, it takes about twice as long at 27 minutes.
Surgical masks protect twice as long as cloth masks at 1 hour. N95 masks on both the infected and uninfected person have the most protection at 25 hours. This study was done before the spread of the very infectious Omicron variant so the amount of time to spread the virus may be shorter.
Time to Transmit an Infectious Dose of COVID-19
| Person Not Infected Is Wearing… | ||||
| Person Infected Is Wearing… | Nothing | Cloth Mask | Surgical Mask | N95 Mask |
| Nothing | 15 min | 20 min | 30 min | 2.5 hrs |
| Cloth Mask | 20 min | 27 min | 40 min | 3.3 hrs |
| Surgical Mask | 30 min | 40 min | 1 hr | 5 hrs |
| N95 Mask | 2.5 hrs | 3.3 hrs | 5 hrs | 25 hrs |
Based on this study, we highly recommend wearing N95 masks. N95s respirator masks are regulated by the National Institute of Occupational Safety and Health (NIOSH), a division of the U.S. Centers for Disease Control and Prevention. N95s can be often identified with two elastic bands the wrap behind your head.
If N95s are not available or are too expensive, a surgical mask still gives reasonable protection. Double masking, or wearing a surgical mask with a cloth mask over it could also provide additional protection. We do not recommend cloth masks unless no other types of masks are available.
Other masks, such as KN95s and KF94s, also provide a high level of protection against COVID-19. KN95 respirators have ear loops and are designed to meet Chinese standards for medical-grade masks. KF94s (KF stands for “Korean filter”) fold flat and are usually made in Korea.
It is important to be careful when buying N95s, KN95s, or KF94s because there are many fake masks out there. NIOSH has determined that about 60% of evaluated KN95 respirators were poor quality and they did not properly protect the wearer.
With the increase in fake masks being sold in many places, such as Amazon, it makes it hard to know which ones are safe. The easiest way to tell if your respirator is NIOSH-approved is to search for it on the NIOSH Certified Equipment List (CEL) or buy from a reputable supplier. Another way to identify a NIOSH approved mask is to look for the phrased “NIOSH approved” on the packaging.
The American government is distributing NIOSH-approved N95s throughout the country. You will be able to get free N95 masks from your local pharmacy or community health center.
No matter what type of mask you wear, it is important to have a mask that fits. A properly-fitting mask should cover your mouth, nose, and chin, and should fit snugly over the face without any gaps between the mask and the skin. Masks that have a nose wire across the top can also further prevent air from escaping out of the top of the mask.
Wear N95 or surgical masks properly in public, when in contact with people outside of your household, or when you test positive. Along with getting the COVID-19 vaccines and booster, masks remain a very important way to avoid getting COVID-19 to protect ourselves, our families, and our community.
To find a COVID-19 vaccine or booster near you, go to https://www.vaccines.gov/.
To volunteer for a clinical trial, go to https://www.researchmatch.org/.
