Hi pebee2,
It varies to some degree by manufacturer depending on the specifics of their compounding formula but they each tend to have their own type of smell. There is more about the “typical” smell of Talalay and Dunlop latex in post #2 here.
All the latex you are likely to encounter (either synthetic, blended, or natural in Talalay or Dunlop) has been tested by Oeko-Tex or Eco-Institut for harmful substances and VOC’s so the smell isn’t harmful.
Phoenix