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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.

I ask because of a discovery I made during research is that while being poisonous to the central nervous system, methanol is a natural endogenous compound found in normal, healthy human individuals.

One study found a mean of 4.5 ppm in the exhaled breath of the subjects. https://iopscience.iop.org/article/10.1088/0967-3334/27/7/007

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  • $\begingroup$ The probably origin of exhaled methane is anaerobic gut bacteria and archaea (yes there are always a few archaea in the gut). $\endgroup$
    – R Stephan
    Commented Dec 18, 2020 at 7:10

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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.

http://en.wikipedia.org/wiki/Biological_functions_of_nitric_oxide

http://en.wikipedia.org/wiki/Hydrogen_sulfide#Function_in_the_body

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

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    $\begingroup$ I always understood that NO, when used as a neurotransmitter / second messenger, is in solution, i.e. not gaseous. $\endgroup$
    – Konrad Rudolph
    Commented Aug 15, 2012 at 21:01
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    $\begingroup$ Would these gases be extreated from the body in gasous form? $\endgroup$
    – Gabriel Fair
    Commented Jun 9, 2015 at 22:21
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H₂O is emitted through respiration and perspiration.

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There are 100+ gas phase compounds that come from humans.

enter image description here

Find other information about most of these families of compounds from wiki.

Full list of compounds is here

Methods and findings are here

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    $\begingroup$ A few spontaneous comments: 1-octen-3-ol and similar compounds are fungal products from lipid breakdown (probably on the skin) so not directly human metabolites. Also, cymene (and others, I didn't look up the full list) are plant secondary metabolites, i.e. essential oil components presumably from eating plant food with subsequent exhaling and/or pooping. Humans cannot make these themselves. $\endgroup$
    – R Stephan
    Commented Dec 16, 2020 at 17:34
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    $\begingroup$ Oh golly that's interesting. Perhaps that would be a comment for the OP, i.e. that methane is not actually made by the cells of the human body. There are perhaps symbiont funghi on humans according to current research on microbiology. $\endgroup$
    – bandybabboon
    Commented Dec 16, 2020 at 18:10
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    $\begingroup$ Yes human skin fungi are mainly from genus Malassezia. $\endgroup$
    – R Stephan
    Commented Dec 17, 2020 at 21:26
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A key component of body odour is the volatile thioalcohol, 3-methyl-3-sulfanylhexan-1-ol (3M3SH). The structure may be visualized as hexan-1-ol "substituted by a methyl group and a thiol group at position 3 " (pubchem)

A major contributor to the formation of 3M3SH is the commensal bacterium, Staphylococcus hominis, which produces it as a by-product of the metabolism of (odourless) Cys-Gly-3M3SH.

Cys-Gly-3M3SH, "an L-cysteinylglycine dipeptide-conjugated alcohol that is secreted onto the surface of the skin by apocrine glands" (Ref 2), is itself produced as a by-product of human metabolism in sweat glands.

The key enzyme is a cysteine-thiol lyase (C-T lyase), which (among many other interesting attributes), contains pyridoxal phosphate.

References

Ref 1: Structural basis of malodour precursor transport in the human axilla (Minhas et al., 2018)

Ref 2: The molecular basis of thioalcohol production in human body odour (Rudden et al., 2020; Nature (Scientific Reports))

Ref 3: Know sweat: scientists solve mystery behind body odour (The Guardian, July 2020)

Ref 4: Structure of 3M3SH at pubchem.

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