With a normal virus you would be right... Let's hope you're right with an engineered one...
I'm concerned the Chinese were spraying down cars... cars that are out in the sunshine most of the time. We need to watch what they're doing (not what they're saying)... because they know the nature of this virus. And what it lives on and what kills it.
Spraying down surfaces in public is probably going after the bottoms of human cell chunks or mucus particles. Sunlight only penetrates so deeply and there are probably numerous dark pockets on surfaces at that level of tiny.