I used to smoke. I think that the tobacco smoke I used to inhale regularly was WAY worse for me than whatever I might breathe as a result of bike commuting.

A slight non sequitor, but I'm reminded of when I was in Peace Corps, and volunteers wanted an official ruling from medical staff about the real health impact of going to the Chernobyl zone. Answer in a nutshell - smoking exposes people to WAY more carcinogens and cancer risk than a day trip to Chernobyl.

I don't mean to discount efforts to clean up our air, but just suggesting there's no real reason to be all freaked out by this article/study, which, as many have pointed out, contains some serious flaws anyway.