However, “zero-emission” is also impossible in living areas! Certain volatile substances are always being released into the air – from detergents, clothing, foodstuffs, building materials and basements (e.g. radon). Just the air that is breathed out by people alone causes indoor air pollution; this would quickly become unbearable if no ventilation takes place. That was exactly what Max von Pettenkofer realised already in the 19th century. This is just as true today – in fact it is even more important today because in these modern times we are surrounded by even more substances than before, like it or not.
There are two other things that have changed:
- Buildings are more airtight; draughts are not acceptable any more.
- There are no stoves any more in the homes. From the ventilation perspective, stoves function like exhaust systems.
Consequently, a sensible ventilation concept is of utmost importance today, even if all efforts are being made to keep indoor air pollution as low as possible.