This chart from WHO shows China well down the list. Does it mean something that the five worst offenders are Islamic? And what does PM2.5 mean? This is a catchall definition of pollution that includes all particulate matter under 2.5 micrometers in size. That means four hundred specks would make a row less than one millimeter long. This is stuff that you breathe in and out and can float for ages in the breeze. H/T Zero Hedge.