India, Delhi is currently suffering from air pollution
which is 7 times higher than the limit rated there as harmless
The inhalable lethal particles PM2.5 fine dust are 418 µg/m3. The WHO classifies 10 µg/m3 as harmless
Among other things, fine dust is produced during the combustion of fossil fuels.
A limit value of 25 µg/m³ has been in force in the EU since 2015 and is to be reduced to 20 µg/m³ from 2020.
The operation of laser printers also releases fine dust, referred to here as toner dust.