Those masks are not effective in filtering out viruses. I think it is mainly a politeness thing, though talking to a person wearing one is pretty irritating.
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Name : CaroleK, Gender : F, Sexual Orientation : Straight, Race : White/Caucasian, Age : 39, City : Mito, State : NA, Country : Japan, Occupation : teacher/writer, Education level : Over 4 Years of College, Social class : Middle class,