I remember back in 2004/2005 I was in Taunton, Somerset and usually had to go to London for some meetings. I usually took the FGW train to London Paddington and while I had to wait for my train there I discovered that almost all the trains leave their diesel engines on while waiting for the next departure. As you can see in the pictures London Paddington railway station has a roof and all the diesel fumes will stay inside this station. It's not like it is totally full of it but you can see the deposits of the Diesel fumes everywhere especially in the upper half of the dome. And of course you can smell it.
It was really smelly and I reckon it's not really healthy. I was only a frequent traveller but what about people who work there. I was never able to ask an employee about this but it has to be really dangerous for your lung, I guess.
For the London residents or people who travelled through Paddington recently.
Is it still full of Diesel Fumes or has something changed there. Or is it not really dangerous but just a bit smelly?