Air Quality Monitor Indoor & Outdoor for PM2.5 Particulate Matter, Compact Portable Pollution Detector Meter BAIVON Air Quality Tester for Home Office Car Travel Use

So much in the media about PM2.5 pollution: it's terrible levels, London mayor's ULEZ expansion, wood burners dangerous etc. etc. But getting this simple meter showed be what a load of political rubbish nearly all of that is. With 'excellent' being anything below 50, I'm seeing 4-12 in my house in London, and much the same outside. Same in a house with a wood burner. Maybe dangerous PM2.5 levels in a few places in London (e.g. at diesel bus stops) and one the deep tube lines (350+ we're told - but not by TfL of course)