I get far less pollution whenever I commute by bike. Part of my commute involve riding a train which rail is high above city street. When I do have to drive, I usually inhaling my daily dose of smog in stopped freeway traffic.

Part of life irony is that one of my car is a gross polluter which is going to the junk yard soon (reason why I commute by bike). With that being said, I worry more about pollution while driving instead of biking. I seldom get other car tailing me behind the "curtain of smoke" but too bad I cannot use some of that smoke to keep cars off of me when I am biking