Dr. Cillian De Gascun:

That is a great question. I am not aware that data exists in that context. We know that masks are not 100% perfect. There are different types of mask so it depends which mask a person is wearing. In essence, if a person has a medical-grade face mask, it is not sealed to the face but tied around the ears. There will be air escaping, typically over the bridge of the nose, around the side and perhaps under the chin. If a person is wearing one of the higher-grade medical masks with a filter, then it should be completely sealed. It depends on the mask the person is wearing. Broadly speaking, a mask is better and being farther away is better, but I cannot try to give Deputy Doherty an absolute number on that.