Around the world we see different ethnical groups who have different physical characteristics.
Same goes for smell, which is a combination of the sweat and bodely fluis you produce over the skin, natural feromonal effect and the microbial culture that inhabits your skin and sweat intense regions like groin, armpits, etc.
An african descendend person will smell different from a mexican for example. Nothing to do with hygiene. (well, if its extremely bad everyone stinks, but this is about natural odor).
Why do we sense the african smell more quickly ? Simple. we are used to familiar smells, and notice them less, the body will be less sensitive towards it (which is why you can stand your own farts, but not from someone else). However, when picking up other odor's, they can appear stronger.
According to the 40 y/o blonde, for some women the scent is attactive, for others not.