Places that sell new tires have a unique smell. Chemically what is that smell?
Pep Boys always has that smell.
Tires are made of synthetic rubber and are a petroleum product (main reason they’re so expensive) so that has a lot to do with the smell.
I like that smell. Especially when I’ve just put new tires on the car my garage is saturated with that smell in the morning. Smells like double the recommended speed limit on the on/off ramp. 
That smell is due to volatile organic compounds (VOC) in the vulcanizing accelerators in the tires (that helps crosslink and mechanically stiffen the styrene-butadiene “rubber” of the tire matrix), the phthalates (that help selectively elasticize the tire) and the mold release compound (which helps the tire come out of the mold after curing). The VOCs boil off pretty rapidly during cure. Mold release (which also makes new tires shiny) wears off after a few hundred miles. The tire will continue to outgas entrained phtalates as it wears through its life.
Stranger
I was going to say rubber but nm.