The nature of the weave or mesh of fabric making up a mask, as well as its closeness of fit against the face, determine the chances infected droplets will pass into a new host.
Most kinds of material held in front of the nose and mouth are considered to be better than no barrier at all, though tests using lasers to detect particle transmission hint that polyester neck fleeces could break larger droplets down, helping proliferate them further as aerosols.
In the very least, wearing a layer of cotton such as that provided by a t-shirt could reduce the risk of an infection being passed by as much as 24 percent over 20 minutes of exposure.
But there are better solutions.
Do I need a N95 face mask?
Ideally, a properly fitted mask regulated to screen virtually all concerning airborne particles would virtually eliminate the risk of infection, even while standing in a room swarming with virus particles for a quarter of an hour or so.
Such specialised resources are in short supply, so highly efficient N99, N95, and surgical masks should be left to healthcare workers who face a high risk of infection, or people who face significant risk of complications from symptoms.
Can I make my own face mask?
For most people moving through a public space, homemade masks consisting of two to three layers of high-thread-count cotton or chiffon are considered to be more than adequate.
Remember to wear them responsibly, remove them properly, and give them a good wash regularly.
Masks that contain valves do little to protect others from your virus-packed mucus droplets, so are inappropriate for community protection. Leave them in your drawer for next bushfire season.
All Explainers are determined by fact checkers to be correct and relevant at the time of publishing. Text and images may be altered, removed, or added to as an editorial decision to keep information current.