@RidleyDM @DrLeanaWen I've even noticed color effects, where in some areas people wear lot of surgical masks but in certain neighborhoods you see a lot more black ones rather than the standard blue.
@RidleyDM@DrLeanaWen我甚至注意到了颜色效应，在一些地区人们戴很多外科口罩，但在某些社区，你会看到更多的黑色口罩，而不是标准的蓝色口罩。