By “unique” I don’t mean relative to every other person on the planet at any one time.
By “consistent” I mean over some physiologically healthy time-period in years, when, at least for this question, the person’s GI track is operating on all four cylinders.
The biggest variable, I would think, is the diet.
For the sake of argument–and here I expect the parameters of the argument to change–let’s start with one relatively consistent national/ethnic “cuisine.” That is, someone doesn’t suddenly switch to an all garlic and beans diet (but again, perhaps consistent physiological processing produces a consistent chemical signal).
Whether a dog can inform us of such discrimination is immaterial. I suggest them because I believe their odor discrimination is finer than any gas analysis system developed, but I may be wrong. Along those lines, that dogs can analyze in real time is amazing, but again I’ll leave that out as a factor.
You’ll never guess in which room I was sitting when I formulated (but not typed) this post.
My farts are not even consistent to my own nose from day to day. So you’re going to have to find some invariant part of a pretty widely varying signal if this is going to work.
I believe our best hope is that the unique communities of gut bacteria that inhabit us all may leave a slight signature. But I’m not sure how that would work. Perhaps a small amount of fecal matter makes its way into the gas cloud that could be collected and genetically analyzed?
You’re probably out of luck if you think the ratios between each gas/volatile component will be both consistent and distinct for each individual though.
Compared to most birds our noses are a marvel of efficiency ;).
Short hijack:
Not accusing you of this, but there is a tendency to downplay humans as being all brain with no physical advantages at all of other animals. Lots of emphasis on where we fall down compared to other critters. But we’re actually very well-designed for what we’re designed for - your cat may have better night vision than you, but it has worse close focus, color vision and fine detail perception.
After reading the OP I wasn’t sure if a dog was being eliminated from this question.
If a bloodhound can track a person’s scent from their clothing I don’t see why one wouldn’t be able to pick up that scent within a fart, sneeze or breath.
No real reason to believe the latter claim, though some animals are able to detect certain smells at considerably lower concentrations than humans are.
As for consistency, it’s hard to tell, because while the most salient odorants may be variable, day-to-day, there may well be other, detectable, odorants, which are consistent on a per-person basis. I would guess that the colon-cancer sniffing dog work is the first place to look.
Fart odors are also mediated by your intestinal bacteria. I can always tell the difference between my farts and someone else’s, during the unfortunate times when someone else farts in my vicinity. Of course I know intellectually that it couldn’t have been my fart because I know I didn’t do it, but I can still smell the difference. Although to be sure we’d have to have a double-blind test. :eek: