Flat on busy road - exhaust fumes a major problem?

[absolutelyflawed]

Not sure how big an issue this is - am looking at a flat where DC bedroom would overlook a crossroads / traffic lights where cars are queuing for most of the day.
So... If I wanted the window open would this be a health hazard?

Awful imo.
Near me there are flats next to a busy road and they have some sort of air purification system. But what if you just want to open the window - you can't because it's so grim.

What level of traffic are we talking though? I think you can check air quality in your neighbourhood online - maybe try that? Is there anywhere slightly less polluted you could move to? I don't think you should chance it really.

Horrible for adults, never mind kids.