Well it says people with a high blood concentration of these chemicals have a 4x increase vs. those with a low concentration. That sounds bad but it might not be. If your odds of developing cancer in the low concentration group are 1 in a million, then your odds in the high concentration group are only 1 in 250,000 which isn't exactly great but isn't terrible either. On the other hand if your odds in the low group are 1 in 10,000, then in the high group it's now 1 in 2,500 which is pretty bad.
All that is also ignoring that the article never directly says cars are responsible, only that the chemicals are present in them, and that people with a high blood concentration of those chemicals have a higher risk. Time is also never discussed. Does it take 80 years of near constant exposure to reach "high blood concentrations", or are we talking like 5 years? The article is just too nebulous and vague. It shows some correlations, but seems to fall short of both causal links and quantifying the actual risks.