Regarding old buildings - it also applies to cities. I once seen somewhere that Wrocław was designed to have air flow through the streets freely to take out co

Regarding old buildings - it also applies to cities. I once seen somewhere that Wrocław was designed to have air flow through the streets freely to take out coal hearing induced smog. Now, after the war, Polish architects unaware of that redesigned some of these airways and even though coal burning is almost non-existent smog levels are rising. Cars and loss of greenery contribute to it but one can only wonder how good air would have been if they would follow the original plan.