I have no certainties and you won't find any in that post. Even if the science re masks became miraculously strong (which it can't, for reasons I've given, but hey ho), there STILL wouldn't be any certainties. There never are in science. The science behind global heating is rock-solid but still there are no certainties. Ironically, you make this assertion, which is unsupportable by evidence, as a certainty: "So I mask for myself and my neighbor and make encounters 70% safer." Like to tell me how you arrived at that??