I Remember It Well

If you've never smelled New York City, you've got a chance now. I can't vouch for the accuracy of the smells but from the descriptions it sounds right to me.

http://www.guardian.co.uk/books/2011/sep/20/scratch-n-sniff-guide-new-york

I would add a seasonal line.
New York in the Summer- urine wafting up from the subway vents, hot pretzels at night, pizza, stale trash juice, beer vomit, cotton candy, sweating fire escapes...
New York at Christmas- chestnuts, wet wool, metallic steam radiators, pine boughs, soups in the delis, peppermint, people's coffees...
New York in Spring- defrosting gray snowbanks, uncovered trash, that rusty smell after it rains, the earthy Central Park smell, cut flowers outside the corner stores...

It could even get particular to the boroughs, as they all have their own idiosyncratic odors too.
Yes, New York is a feast for the senses. I hope the book does it justice. She has more planned.