Indoor environment factor · measured in µg/m³
Acetaldehyde
Also: ethanal, acetic aldehyde, acetaldehyde
A small, highly volatile aldehyde with a sharp fruity smell. Indoors it is the second most abundant carbonyl after formaldehyde, produced by combustion, by fermentation and by the reaction of ozone with the terpenes a household brings in.
Where it comes from indoors
Acetaldehyde arrives by three routes that rarely act at once, and telling them apart is most of the interpretation.
It is a combustion product, so tobacco smoke, candles, cooking and any unvented flame raise it. It is released by materials, particularly wood and wood-based products, and by alcoholic drinks and fermenting food. And it is made in the room itself: the reaction of ozone with terpenes and with skin oils produces it as a secondary product, which is why a room can hold more of it than anything in the room emits.
It is almost always measured alongside formaldehyde, by the same sampling method, and usually found at a lower concentration. The two are not interchangeable: they have different sources, different reactivity, and different health classifications, and a value for one says nothing about the other.
What the studies report
| Linked to | Effect | Population | Study design | Source | Checked |
|---|---|---|---|---|---|
| — | other 36.0 | — · car cabin | measurement study of 24 car cabins in Japan: volatile organic compounds and aldehydes sampled inside the cabins with outdoor air for comparison, against the advisable values of the Japanese Ministry of Health, Labour and Welfare, with a screening-level risk assessment | F-1120 Car indoor air pollution by volatile organic compounds and a… (2016) | 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.
Identifiers
Cite this page
Coridum Research. Acetaldehyde. Coridum Knowledge G-0200, 16 September 2026. https://coridum.com/k/G-0200/