Respro pollution masks
I was riding my push bike 13km to work, each way, from West London to the city centre and then back again. I wore a carbon filter respro mask. I highly recommend them.
When I rode my motorbike 45km to the office, my shirt collar, poking above my jacket, was almost black from the road pollution. When I cycled, I was really pulling on the air, due to my exertions, so all that crap was going straight to my lungs: a big helping of hydro-carbon derivatives.
I say wear a mask even if its stuffy in summer: your lungs are worth it, plus the extra resistance helps develop your intercostals!
Adventure: it's an experience, not a style!
(so ride what you like, but ride it somewhere new!)