I'm sure with fuel cell technology, in 10 or 15 years cars and buses will be spewing harmless Oxygen and water vapour directly on cyclists as they ride by
The auto companies are all working on this technology, one of them (Daimler-Chrysler?) has bought a large chunk of Ballard Technology in Vancouver. Ballard is the company that has come up with a lot of the fuel cell advances and the trial buses.