Main pollution and cause of many diseases = nuclear tests conducted from 1945 to present days. Just try adding radiation from at least all know nuclear explosion together and you'll see that pollution from cars is a joke compared to nukes.
For example, nuclear bombs thrown in Japan were tiny compared with amount of radiation from Chernobyl.
Chernobyl released
890 times as much caesium-137 as the Hiroshima bomb, released
87 times as much strontium-90 as the Hiroshima bomb and when the iodine-131 release is compared between the events (decay corrected to three days after the event) then Chernobyl released
25 times as much as the Hiroshima bomb. When the xenon-133 release is compared between the events (decay corrected to three days after the event) then Chernobyl released 31 times as much as the Hiroshima bomb.
Air traffic is something different. I remember reading one old analysis which said that one 747 pollutes as much as 1500 cars. Multiply flights per day with 1500 and compare that with number of cars in use AND, most important of all remember that airplanes don't have catalysts.
Sorry for the post with no particular order