Loads of people say, “How can there be any downside to wearing a mask to stop #Coronavirus?” And it's true, you'd think at the very least a facemask outdoors can do no harm. Since I've now done about 25 interviews on the subject I thought I would summarise the arguments against: 
1. You touch your face more. You may even touch *under* the mask because your nose and lips itch.
2. Masks become dirty, and could well be a place where germs gather, like the handkerchief you've kept in your pocket every day this week.
3. Masks are needed by doctors and nurses. There is a powerful argument that any mask worn by a non-medical person is a mask stolen from the NHS. If 45 million members of the public decide they need masks, what does the health service do?
4. The novel Coronavirus microbe is so small that you could put 10,000 in a queue and it would be only 1mm long. Stopping microbes with a facemask is like trying to catch plankton with a dolphin net.
5. People don't know how to wear masks. Already the @nytimes has felt the need to publish an article instructing people not to wear them on their chins; or on the mouth only; or to chew them while wearing them. This does not bode well. nytimes.com/2020/04/10/wel…
6. Masks give a false sense of security. You might well have seen people in masks behaving in a way that suggests they think the 2m distancing rules do not apply; someone in a mask leant across me in the supermarket the other day, presumably thinking they were invulnerable.
7. We may have misunderstood why people in Asian countries wear masks. For many it is convention to wear one when you yourself are ill, so you don't pass the illness on. They're also worn in Asia because of pollution.
8. Social distancing has reduced our ability to communicate with each other. Masks reduce it even more. Not only that, a person who speaks while wearing a mask is often difficult to hear. Thus people move closer to them, which puts them in more danger.
Important note — these are not my personal views, and although I don't wear one, I'm not anti-mask myself ... I'm just summarising all the arguments against which I've heard since the crisis began, and trying to answer the question: “But if it does no harm, why not?”
I'll add this, because it shows that the way something is used is just as important as the thing itself. This photo basically destroyed the argument for gloves.
This further point has only just been made to me:
At least this shopper thought about it.
