The main factors of urban air pollution are nitric oxides, carbon monoxide, and what is called in german "Feinstaub" (very small carbon-rich particles from diesel exhaust). However, do not forget heavy metals: street dust is especially metal-rich and is swept into the soil near the streets where children and farmed plants can take it up. Lead is a heavy metal that can be breathed in with the air. Last not least noise over a certain threshold is proven to be a cause of illness, even loss of life time (10 years near an airport, if I recall correctly, but airport noise is getting better while machines become more fuel-efficient).
To answer your question one would have to look at every single factor. Lead accumulates in bones and destroys your brain. I just see Brazil banned it too in the 80's so this one killer is no more.
I have found a meta-study that reviews about 80 papers on the subject, especially the Sao Paulo studies, so this should fit exactly your questions: