Scientific American: Ironically, many communities build dedicated bike lanes right next to busy bus routes, unintentionally ensuring that bicyclists breathe in maximal diesel exhaust Aside from the obvious physical safety considerations (especially when talking on a cell phone!), biking on highly trafficked roads exposes riders to considerable amounts of fine particles, nitrogen dioxide and volatile organic compounds spewing out of tailpipes. Getty Images Dear EarthTalk: I ride my bike to …