@kprather88 @CollignonPeter Also explain how filtering out vehicle exhaust, wildfire smoke, mold, asbestos, lead, common dust, and other pathogens from air in dirty old schools is not beneficial regardless.
@kprather88 @CollignonPeter 还要解释如何从肮脏的旧学校的空气中过滤掉汽车尾气、野火烟雾、霉菌、石棉、铅、普通灰尘和其他病原体无论如何都是无益的。