@grrttweaver @TaakiTiki @BrianLenzkes Depends for what. To provide a high degree of personal safety in a hazardous environment? No. To reduce overall spread by a measurable amount? Yes.
In terms of physical aerosol particles, CDC measured reduced concentration at about 70%, enough to claim some (least) protection.
@grrttwaver@TaakiTiki@BrianLenzkes取决于什么。在危险环境中提供高度的人身安全？否。以可测量的数量减少总体差价？对
在物理气溶胶粒子方面，CDC测量到的浓度降低约为70%，足以要求一些（最少）保护。