@i_petersen @ZerocovidD @_TheAncientOne_ Italy HEPA classroom study supports this. HEPA filters -> 80% reduction.
@i_petersen @ZerocovidD @_TheAncientOne_ 意大利 HEPA 课堂学习支持这一点。 HEPA 过滤器 -
@i_petersen @ZerocovidD @_TheAncientOne_ Italy HEPA classroom study supports this. HEPA filters -> 80% reduction.
@i_petersen @ZerocovidD @_TheAncientOne_ 意大利 HEPA 课堂学习支持这一点。 HEPA 过滤器 -