That's the finding of researchers in Europe, who studied children in 10 cities and recently published their findings in the European Respiratory Journal. In fact, as much as 14 percent of all asthma cases are being blamed on traffic exhaust. This makes car exhaust more harmful than previously thought, since previous research stated that traffic simply made already-existing asthma cases worse.
What happens now is, well, who knows. Last year, the World Health Organization found that diesel fumes causes cancer, but as best we can tell, there haven't been any big new regulations issued because of that finding. The story is becoming clearer, though: the sooner we eliminate dirty vehicles from the environment, the healthier we'll be.