call the mayor's office, they have a hotline for stuff like this. Not sure how useful it is

(201) 547-4900
(201) 547-5555.

I'd suggest that the fumes are a health hazard, if not carcinogenic. Most of the workers wear face masks and are ignorant of the dangers due to the fact that they are often new immigrants. I'd call the health inspector or even the EPA to look at the chemicals involved with the process.
It doesn't matter who was in the building first - A health hazard is a health hazard and even the workers need to be protected and especially the clients - Full disclosure should be available on the chemicals used.

Not to sound like an a$$ but was the nail salon there when you moved in?

HI I live on top of a nail salon (west side ave)
My building doesnt have windows in the hallway...most of the time i can smell nail salon fumes walking up the stairs...I try opening the doors to get air in but my landlord is a pain in the neck and complains when I do so

I have called the inspectors to come which they did and the guy said dont call them again he will fix it...who should I call next? I forgot the # i called the 1st time...also are these fumes dangerous????