Experts have just resolved the public health controversy regarding face masks. Right now, the best thing to do is to wear it.
Joseph G. Allen, director of the Safe Buildings program at Harvard, told The New York Times, "you protect yourself, protect others, and prevent yourself from touching your face" when you wear a mask.
With coronavirus cases still growing, it's more important than ever to wear a mask. You can see just how significant a swath of fabric can be in battling the pandemic in this animation.
How do masks really work?
Masks come in many types and fabrics, but they work in the same way in general. Layers of fibers collect large respiratory droplets and smaller airborne particles known as aerosols that can carry the coronavirus.
This process is known as filtration, and filtration efficiency is called a substance's capacity to capture particles.
Most common fabrics outperform tightly woven cotton. The most powerful is a nonwoven material like that of an N95 mask.
What makes an N95 mask so unique?
Let's look at how filtration functions at the microscopic level in more detail.
Here is how a cotton mask's fibers are compared to aerosol particles of varying sizes. The smallest particles' scale is around the coronavirus, but it usually moves within the larger ones.
As they pass with the air stream, the fibers present a dense forest that the particles must traverse. The laws of physics impact how the fibers interact with the particles and how well the mask can absorb them.
What about those other masks?
Loose-fitting masks or those rubbed against facial hair make it possible to leak aerosols. There will be a wide surface area for a good mask, a close fit around the edges, and a form that leaves room around the nostrils and mouth.
This provides a broader breathing zone for the particles to catch and increases the chance of a fiber being encountered. Some masks have valves that make exhaling smoother, but these valves do not capture the aerosols you breathe out without filters, so they do nothing to protect others.
I don't have an N95 mask; what happens?
The gold standard is a well-fitting N95, but do not panic if you can't get your hands on one. The combined filtration efficiency improves when everyone wears a mask.
Let's assume half of the particles you exhale are removed by the mask you wear. The particles that escape scatter and are diluted further through the air. The particles that ultimately enter the front of someone else are filtered again and the amount that gets through is reduced.
"It's become clear that cloth masks, even though they're not as effective as the N95s, are still effective at reducing transmission," said Linsey Marr, an aerosol expert at Virginia Tech. "Even if you're not achieving that 95 percent reduction, something is better than nothing."
The risk of transmission is further minimized by adequate ventilation and social distancing. And the mutual gain goes up if everybody wears a mask and keeps their distance.
Check out more news and information about COVID-19 in Science Times.
