Here in Mauritius, masks are mandatory everywhere where people meet. Do you know the feeling that something is missing when you drive your car without using seat belts? A missing mask in public now gives me the same sensation. Weird.
Most people use their masks correctly, that is, covering mouth and nose. Some are not covering their nose, and they could as well not wear a mask. Keep your distance. As we know by now, Covid-19 is airborne and transmits via droplets. A correctly worn mask will catch most of those droplets, on both inhalation and exhalation. It will protect you from infection by others, and it will protect others from infection by you.
It’s a two-way system, with the purpose of abating the spread of the virus. It’s thus an easy and cheap measure to decrease the risks of infection, and all that comes with it. And it works for all existing and new variants of the virus.1
It even sufficiently works with the light surgical masks, at least for those of us who are not at elevated risks. If you are a health care worker, or come in contact with lots of strangers on a daily basis, say, in customer service, you should use an N95-grade mask. With surgical masks, make sure you have a tight fit. The metal strip across the nose does have a purpose. Breathing slowly also helps, as it avoids building up lots of pressure behind the mask, which can make some of the airflow go around the borders in lieu of through the filtering fabric. This can also happen with N95s.
So far so good.
However, there’s a type of mask that has an exhale valve. It’s the plastic thingie. The valve opens when you breathe out, to make exhalation, and thus wearing a mask, easier. Obviously, that kind of mask defeats half of its purpose: the exhaled air is not being filtered. You protect yourself, but don’t protect the others. It’s the egoist’s mask.
This has been evident to me since I saw this kind of mask for the first time, simply based on logical thinking. I have explained this to people, with or without success. Mostly with. But I had never bothered to check for confirmation. It’s so friggin’ obvious.
I finally did. Check out this article at NIST, and the videos. Scroll down to the second video.
Regarding protection of the others, users of masks with valves could as well not wear one. Keep lots of distance.
To conclude, let me underline two points.
- “Egoist’s mask” gives a catchy title. But most people just purchased their masks at the pharmacy, or on-line, without giving all this any thought. They will understand the reasoning, especially after watching that video, and change their masks for the benefit of the people around them. Most of us are not egoists. Maybe avoid the term when explaining, as your arguments might be received with less resistance.
- The valved masks are not bad masks. They were simply designed for another purpose, namely to protect you when working in a hazardous environment, where you just need to keep yourself safe, not also the other way round. These masks are just being misused now outside their specifications, technically speaking.