Humans exhale all kinds of stuff aside from just CO2, including moisture and other metabolic byproducts depending on what you’re eating. Probably some bacterial

Humans exhale all kinds of stuff aside from just CO2, including moisture and other metabolic byproducts depending on what you’re eating. Probably some bacterial metabolic products from our mouths too. I guess I’m less into the semantic difference between “smell” and “detect” and more whether it’s the CO2 they’re following or something else we exhale regularly.