Update: more details on this here. There’s a rationale for this, but it may or may not be a good one!
This will be a very rare link indeed for me, to the People’s Daily Twitter account out of China. I’d seen some clips like this before, but wasn’t sure of their provenance. This, though, is an official organ of the Chinese state – none more so – showing all sorts of white-fog-spraying devices being deployed outdoors, with the caption “Full-front disinfection work has started in #Wuhan, an effort to contain the spread of #coronavirus“.
But what the heck? I am at a loss to say what this stuff might be. I asked the same question on Twitter, and the answers were mostly variants on my own thought, that it’s basically “safety theater”. The problem is, there are such things as aerosol spray insecticides. And there are aerosol spray general antimicrobials (although I have trouble believing that you could get much good out of them deployed in the fashion shown, on city streets). But there are, to my knowledge, no open-spray viricides. I mean, viruses aren’t alive, for one thing, and the sorts of things that are used for viral contamination depend on broad denaturing chemical activity (think bleach) or physical wiping/sequestration (cleaning surfaces off).
I’m not seeing anything like that here that makes any sense. Honestly, I have to wonder if I’m looking at nothing more than fog machine mixture (usually glycerine/water or something of the sort). Maybe there’s something in the mix that someone thinks will do some good against coronavirus particles – I doubt if they’re correct, if so – or maybe the whole thing is just meant to show that the Authorities Are Doing Something. Even if that something is just distributing impressive blasts of white fog under the heading of “full-front disinfection”. Whatever that is. This sort of thing actually makes me have less confidence in the Chinese government, and I wonder how it’s going over among the intended audience.
Ideas, speculation, and pointers to other sources of information are welcome in the comments.