@ElRay Good point. The room filter does not replace peronal protection masks! Of course, whenever possible and needed (orbital sanding, routing, ...) I wear an FFP2 mask and connect a vacuum cleaner for dust extraction. But this one in addition reduces particles floating around in the air significantly quicker and filters down to 1 micron size. A lot of the critical particle matter between 1 and 10 micron is filtered within a 10 minute break this way. At least in a small workshop like mine.