Wearing a face mask has been shown to be one of the best ways to stop the SARS-CoV-2 coronavirus, the virus responsible for the COVID-19 disease, from spreading.1,2 Masks can block infectious droplets and aerosols from being transmitted from person to person.
But should everyone be wearing the same mask? Let’s break down how exactly masks help stop the SARS-CoV-2 coronavirus from spreading and look at which type of mask is best for your lifestyle.
How do face masks stop COVID-19?
The COVID-19 coronavirus (SARS-CoV-2) is a mucosal-based virus. It spreads by infecting mucus that lines your nose, throat, windpipe, and lungs.
There are three main ways that mucosal-based viruses are spread: via large droplets, shared saliva, and airborne aerosols.
Large Droplets from Coughing and Sneezing
When you cough or sneeze, you send mucus flying through the air in the form of coarse or fine droplet particles. Most of these droplets fall out of the air quickly due to sheer gravity.3,4
These droplets land on the ground and on nearby surfaces that other people can touch. Another person can infect themselves by touching these contaminated surfaces and then touching their own eyes, nose, or mouth.
Saliva on Shared Surfaces and Objects
Mucosal-based viruses can also be spread by sharing saliva when you, for example, drink out of the same glass, use the same utensils, or kiss a person.
Keeping your mask on can help stop the spread of the SARS-CoV-2 coronavirus through saliva.
Microscopic Airborne Aerosols
Mucus-based viruses can also spread through airborne, fine and ultrafine particles as small as 0.003 microns in the air from breathing, talking, and singing.5
Ultrafine respiratory particles are small enough to remain in the air indefinitely. These particles are also small enough to penetrate many basic mask materials.
What is the best face mask?
When it comes preventing the spread of the SARS-CoV-2 coronavirus, there are two ways.6
First, stop infected persons from spreading the virus by wearing masks. Second, healthy persons can protect themselves from getting it by masks.
Face coverings prevent the spread of large droplets and reduce the spread of aerosols. But they don’t provide the wearer with full protection of microscopic airborne aerosols.
However, the more people that wear face coverings, the more the entire population is protected.
Other masks protect you better than others – these are premium masks that are classified as personal protective equipment (PPE). There is limited supply for these types of high-level protective masks, as they are in high demand for medical workers.
Therefore, the most popular types of masks that help prevent the spread of the SARS-CoV-2 coronavirus are face coverings. There are several types of these masks available: scarves, fabric, and surgical/spit masks.
Scarves & Fabric Masks
This type of mask helps prevent you launching large droplets and infectious aerosols. They also prevent you from touching your nose and mouth and thus from contaminating yourself.
These masks DO NOT fully protect you from fine and ultrafine airborne mucus particles, so make sure you stay 6 feet away.
Surgical Masks (AKA Spit Masks)
Surgical masks are also good for helping stop coarse and fine airborne mucus particles from coughs and sneezes from escaping and infecting others. They also prevent you from contaminating yourself by touching your nose and mouth. Surgical masks are good for everyday wear if you stay six feet away from others.
Because the material/layers are denser than most scarves and fabrics, these masks will be more effective at filtering finer particles than scarves or fabric masks. But these masks also DO NOT provide full protection for fine and ultrafine airborne mucus particles and aerosols.
KN95, N95, & FFP2 Respirator Masks
These are premium masks (aka PPE) – they protect you and others from infection.
There are two types of these masks: those with valves and those without valves. While the masks with valves make breathing easier, there is a concern that valve allow infectious particles to be released, when worn by an infected individual.
N95 respirator masks are critical for medical professionals who need protection from coarse, fine, and ultrafine airborne, mucus-based particulates. This is because aerosols can build to high concentrations in hospitals and medical offices, where there can be infected patients in a concentrated area.
The most effective respirator masks are made to meet stringent standards. Please make sure your respirator mask meets one of the following standards before buying:7
- N95: United States NIOSH-42CFR84 standard in the United States
- KN95: China GB2626-2006 standard
- FFP2: European EN 149-2001 standard
Respirator masks that don’t meet these standards above may not provide full protection from airborne aerosols and particles.
Remember – these are respirators. Therefore, fit is very important for these types of masks. If the seal around the edge of the mask is not flush with your skin, infected mucus particles can still bypass the mask and cause infection.
During the COVID-19 pandemic, the global supply of PPE respirator masks is scarce, leading to shortages that put medical professionals who need them at higher risk of infection in hospitals and medical clinics.8,9,10,11
Look to the Centers for Disease Control and Prevention (CDC) or World Health Organisation (WHO) for guidance on when there’s a global shortage.12 Although there are no shortages of KN95 masks, there is concern about the quality of such masks. Therefore, make sure you obtain your mask from a reputable source.
Wearing a mask is one of the most important ways we can all help stop the spread of the SARS-CoV-2 coronavirus.
But not all masks are created equal. A cloth face mask is most effective against large droplets if you stay six feet away from others.
Cloth face masks aren’t effective against filtering ultrafine aerosolized viruses.13 You’ll need a KN95, N95, or FFP2 respirator mask for aerosols and for medical environments where particles build up to high concentrations in areas with infected individuals, whether in homes, hospitals or clinics.
No matter what, wear a mask and take every precaution you can!
 Lyu W, et al. (2020). Community use of face masks and COVID-19: Evidence from a natural experiment of state mandates in the US. DOI: 10.1377/hlthaff.2020.00818
 Leffler C, et al. (2020). Association of country-wide coronavirus mortality with demographics, testing, lockdowns, and public wearing of masks. DOI: 10.1101/2020.05.22.20109231
 Van Doremalen N, et al. (2020). Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1. DOI: 10.1056/NEJMc2004973
 Furukawa NW, et al. (2020). Evidence supporting transmission of severe acute respiratory syndrome coronavirus 2 while presymptomatic or asymptomatic. DOI: 10.3201/eid2607.201595
 Anfinrud P, et al. (2020). Visualizing speech-generated oral fluid droplets with laser light scattering. DOI: 10.1056/NEJMc2007800
 Mayo Clinic Staff. (2020). COVID-19: How much protection do face masks offer?
 Centers for Disease Control and Prevention (2020). NPPTL respirator assessments to support the COVID-19 response.
 Chu DK, et al. (2020). Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: A systematic review and meta-analysis. DOI: 10.1016/S0140-6736(20)31142-9
 Centers for Disease Control and Prevention. (2020). Older adults.
 Centers for Disease Control and Prevention. (2020). People of any age with underlying medical conditions.
 Food and Drug Administration (2020). N95 respirators, surgical masks, and face masks.
 Centers for Disease Control and Prevention. (2020). Strategies for optimizing the supply of facemasks.
 Leung NHL, et al. (2020). Respiratory virus shedding in exhaled breath and efficacy of face masks. DOI: 10.1038/s41591-020-0843-2