@RidleyDM @DrLeanaWen There doesn't seem to be much to explain it (for example, if local officials were pushing people to upgrade or providing better masks or such, but I don't think any of that is true in general). It's just a mystery of human behavior.
@RidleyDM@DrLeanaWen似乎没有太多的解释（例如，如果地方官员正在推动人们升级或提供更好的口罩之类的，但我不认为所有这些都是正确的）。这只是人类行为的一个谜。