A very interesting question that I also have pondered before. In the first episodes it is mentioned that she needs to mask the human scent as Vulcans find it revolting.
Ergo she does not smell "human"
I would think that human scent is a combination of all our secretions however miniscule they are up to the famous old people smell.
So the question arises. What is the Vulcan urinary tract like? How do they sweat if at all, saliva - tons of it? Vaginal secretions? Tears? Earwax?
How much of all this is documented in trek lore?
But now that I have ruined our image of T'Pol and reduced her to a bunch of glands on two lovely feet I want to finish with this.
In my dreams there is a sweet flowery scent that fills my entire universe as she gets closer and whispers " I find you agreeable Surak"
Well in that case one may as well ask what Vulcans smell like in general. I wasn't really going to such an in depth scale, but it is interesting to find someone who is as interested in some of the most obscure scientific facts of Trek as I am.
One thing I can gather ( and mind you I am working from some assumptions based entirely on observation here) is that T'pol can't smell too different from us. The crew has no reaction to her scent. (Lets just skip the "writers never thought about it." argument for now.) Now this could be because they don't care, or more likely, that their sense of smell simply can't detect enough of a difference to actually acknowledge it.
Also T'pol later pointed out, that she had become used to the human odor, but that it was difficult to mask. We probably don't smell too bad to Vulcans, so much as our odor is probably more pungent than anything.
Speaking of which, from a Vulcan perspective, and what I know about Human biology, we probably exhibit a strong a strong/ pungent musk odor to them. (Much like the way a Red-tailed fox smells to us.)
Given that it seems they are put off by how pungent our odor is, I gather Vulcan's don't exhibit such strong odors. My guess is she probably doesn't have a very strong scent and would probably smell more like nothing to us. (Maybe something akin to sawdust.)
However all of this is based on circumstance, inference, and extrapolation based on and assumed context. So I could be way off.
I probably should have worded my original question differently. I was referring to her scent based on what you think her personal grooming preferences are. I.E. Does she smell like nothing, soap, or some kind of light fragrance?
Personally, I too believe that she smells sweetly of flowers. It just seems to suit her.
