That’s an interesting angle. In my work I’ve learned that plant odors can be as telling as fingerprints, but only if you know what to look for. The key is how long the volatile compounds linger and how they mix with the air around them. If someone walked through a garden full of mint, rosemary or even certain nightshades, those scents can trail for hours and, with the right equipment, you can link them to a specific spot and time. So yes, herbs can give clues, but you need a baseline and a way to isolate the compounds before you can make a solid connection.

You’re right, the air in a crowded place is like a jumble of scents, and picking out one herb’s trail is tricky. It’s like trying to hear a single song in a packed club. The trick is to use a device that can separate the chemical fingerprints from the background chatter—think of it as a very selective eavesdropper that only listens to the herb’s voice. In practice it’s a lot of work, but a focused sampling and a good baseline can make the difference between noise and evidence.

Right, the numbers are what keep the theory honest. With the portable GC‑MS I’m usually looking at parts‑per‑billion levels for menthol or cineole—good enough to pick up a plant that’s been in the room for a day or two. The key is keeping the air in the sampling chamber as still as possible so the vapours don’t dilute with the background. A practical set‑up would be a small, sealed chamber with a low‑flow pump that pulls air through a sorbent tube every few minutes. Then, on the lab side, you run the tube through the GC‑MS and look for the characteristic peaks. If you keep the sampling points the same in every scene, the only thing that changes is the presence or absence of that herb’s signature. That’s how you make the scent stand out instead of getting lost in the noise.