# Locate people by Oxygen/Carbon Dioxide levels [closed]

I've been challenged to think of some really out-of-the-box ways to locate people, and I had one. I'm 90% sure this isn't reasonably possible (probably only in laboratory settings), but I couldn't find a real answer to this question, so now I'm genuinely curious.

It is possible to locate people's location by fluctuations in the Oxygen/Carbon Dioxide levels in the area (from people breathing)?

I realize this is a really general question, and would depend on a ton of factors (size of the area, number of people, proximity of people to an appropriate sensor, etc). I'm really just looking for a general answer, but in case it helps, I'm referring to a general case of detecting people in outdoor settings (it would be part of a sensor suite that is outdoors and just trying to count/locate people in the general area).

Even just a link to a technical paper that explains human impact on immediate area $\sf{O/CO_2}$ levels would be great - I've come up completely empty looking, everything I find just refers to global warming/overall environment/over thousands of years. Nothing for immediate impact, if there is any.

Edit: This was marked as off-topic? Seriously? This is 100% earth science.

## closed as off-topic by Siv, Daniel Griscom, Jan Doggen, Fred, PontApr 24 '16 at 19:00

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "This question does not appear to be about earth science, within the scope defined in the help center." – Siv, Daniel Griscom, Jan Doggen, Fred, Pont
If this question can be reworded to fit the rules in the help center, please edit the question.

• Indoors, over minutes to hours? Yes. Outdoors? No. – EnergyNumbers Apr 21 '16 at 19:23
• Common sense agrees, and knows this is likely a silly question, but I'd still like some real details and facts to back it up. Don't want to make assumptions. – Chris Burrus Apr 21 '16 at 19:25
• My main worry would be plants since they "breathe in" CO2 and "breathe out" O2. – Barry Carter Apr 21 '16 at 22:13
• Mosquitoes do find you this way, so why not... – AtmosphericPrisonEscape Apr 21 '16 at 23:37
• For what it's worth, this approach is used for detecting stowaways in containers, or otherwise for detecting (but not localising) people in enclosed environments. See armstrongmonitoring.com/store/shop/… for an example product. I'm doubtful as to whether it could be usefully applied outdoors, though. – Semidiurnal Simon Apr 22 '16 at 13:16