Source · category
Bioeffluents (occupant emissions)
Also: bioeffluent, human emissions, occupant emissions, body odour, human bioeffluents
Everything people themselves release into the air of a room — carbon dioxide, water vapour, body odour compounds, skin particles and the products of skin oils reacting with ozone. In a well-built, lightly furnished room, the occupants are the main source.
Where it comes from indoors
Ventilation standards were built on this source before any of the others: the rate of outdoor air per person exists because a room full of people becomes unacceptable to the people in it, and the rate was set by what it takes to keep it acceptable.
The emission has several parts. Carbon dioxide and water vapour come from breathing and are the largest by mass. Volatile compounds come from skin, breath and the bacteria living on both, and they are what body odour is. Particles come from shed skin and from clothing, and are resuspended by movement.
The part discovered most recently is chemical. Skin oil contains squalene, which reacts with ozone within seconds, so a person in an ozone-containing room generates aldehydes and other oxidised compounds at the surface of their own skin — an emission that exists only because the occupant is there.
What the studies report
| Linked to | Effect | Population | Study design | Source | Checked |
|---|---|---|---|---|---|
| Volatile organic compounds (VOCs) | emission-rate 6.3 | — · university classroom | measurement campaign in an occupied university classroom: time-resolved concentrations of volatile organic compounds in room air and in supply air measured continuously with a proton-transfer-reaction time-of-flight mass spectrometer during occupied and unoccupied periods, with the emission factor of each human-emitted compound obtained by dividing the occupant-associated source rate by the occupancy | F-1575 Volatile organic compound emissions from humans indoors (2016) | machine |
| Volatile organic compounds (VOCs) | the compounds compared are carbon dioxide, acetone and isoprene; for acetaldehyde the study found the emission rates equivalent | — · cinema auditorium | measurement campaign in a cinema: volatile organic compounds emitted by seated audiences measured at high frequency with a proton-transfer-reaction time-of-flight mass spectrometer across multiple screenings of three films in a room flushed at a known rate, so that emission rates could be calculated for adults and for children | F-1585 Real world volatile organic compound emission rates from sea… | machine |
Each row is one Finding — a sentence as printed in one study, recorded with its page in the Coridum Knowledge Base. Follow the Finding number for the exact wording and the citation. Checked says who verified the row: machine means every automatic check passed and the surrounding text was read; person means someone read the sentence in the document. Rows are re-checked by a person over time. The studies are curated in the Coridum Knowledge Base; the reading of them together is a Claim, shown separately.
Cite this page
Coridum Research. Bioeffluents (occupant emissions). Coridum Knowledge G-0186, 16 September 2026. https://coridum.com/k/G-0186/