Why does outside air smell like metal?

Question

You know in cities that are hot and humid or if it's hot and it just rained, the outside air smells like metals? I don't know if it's from the trees or from pollution or it's just natural? And if someone goes outside and then comes back inside, that smell is all over their hair and clothes. What causes that? Ions?

Answer 1

Mostly it's pollution from IC engines and rubber particles abraded off of tires.  After a rain there is usually a small amount of ozone and carbonic acid in the air. giving the air a slightly sharp odor.  There might be some small amount of metallic odor coming from air conditioners, and vehicle exhaust pipes.