@PSQ17266 @Kit_Yates_Maths If the classroom has suitably configured windows, AND the windows are open (weather permitting) AND there is sufficient breeze, then yes the filters don't do much and could be turned off. But the former is not always the case. So filters in every classroom is a baseline.
@PSQ17266 @Kit_Yates_Maths 如果教室有适当配置的窗户，并且窗户是打开的（天气允许的话）并且有足够的微风，那么是的，过滤器不会做太多并且可以关闭。但前者并非总是如此。因此，每个教室的过滤器都是一个基线。