Other than CO₂ and Methane what other gases do humans produce or emit?
For example, does skin decomposition, or aerobic respiration emit any special gases that people don't normally realize or know about.
The gases NO, H₂S, CO even have a function in the human body!
Nitric oxide is produced in endothel and neurons as messenger, and in macrophages as cause of nitrosative stress for imprisoned bacteria. Hydrogen sulfide is produced in cysteine catabolism and functions as messenger (only recently discovered). Carbon monoxide appears to act as messenger, too.
Wu, L; Wang, R (December 2005). "Carbon Monoxide: Endogenous Production, Physiological Functions, and Pharmacological Applications". Pharmacol Rev 57 (4): 585–630. doi:10.1124/pr.57.4.3. PMID 16382109
In addition to the comment above, nitric oxide main function is to cause erection in male sexual part. Nitric oxide causes blood to be clotted in soft tissue of penis.