Health outcome · marker · measured in ppm
Exhaled carbon monoxide
Also: exhaled CO, breath carbon monoxide, end-tidal CO, eCO
The concentration of carbon monoxide in a breath sample, used as a marker of how much a person has absorbed rather than of what a room contains. It reflects recent exposure from smoking, cooking or heating and falls over hours once the exposure stops.
What it is
A breath measurement is a measurement in a person, not in a room, and Coridum keeps the two apart deliberately. A room concentration describes what was available to breathe; exhaled carbon monoxide describes what a particular person’s blood actually took up, integrating the time they spent near the source and how hard they were breathing.
It is read through the equilibrium between the gas in the blood and the gas in the alveoli, which is why the figure is usually reported alongside an estimated carboxyhaemoglobin percentage derived from it. The measurement is quick and non-invasive, and it is used both in smoking-cessation work and in field studies of cooking exposure, where it gives a per-person number that a fixed monitor in the kitchen cannot.
Its limit is its memory. Carbon monoxide leaves the blood over several hours, so a breath sample says what happened this morning, not this month.
Indoor factors with evidence
12 of 17 Findings — those with the strongest study design.
| Factor | Effect | Population | Study design | Source | Checked |
|---|---|---|---|---|---|
| Carbon monoxide (CO) | beta 0.038 per one additional minute of cooking in a kitchen without a chimney ppm | pregnant women and their newborns · home | communication from Sri Lanka: pregnant women's exposure to second-hand tobacco smoke and to wood-fuel smoke recorded by questionnaire, expired-air carbon monoxide measured with a breath monitor, and neonatal birth weight and gestational age recorded at delivery | F-0990 Pathirathna et al. Effects of Prenatal Tobacco and Wood-Fuel Smoke Exposure on … (2017) | machine |
| Carbon monoxide (CO) | mean 2.84 | reproductive-aged women · home | descriptive cross-sectional study among 403 reproductive-aged women (15 to 49 years) in the Central Province of Sri Lanka: cooking fuel and respiratory symptoms from an interviewer-administered questionnaire, exposure assessed with a breath carbon-monoxide monitor and carboxyhaemoglobin estimated from it, with logistic regression adjusted for confounders | F-0879 Pathirathna Impact of solid fuel usage on respiratory symptoms among rep… (2022) | machine |
| Carbon monoxide (CO) | mean 1.08 | reproductive-aged women · home | descriptive cross-sectional study among 403 reproductive-aged women (15 to 49 years) in the Central Province of Sri Lanka: cooking fuel and respiratory symptoms from an interviewer-administered questionnaire, exposure assessed with a breath carbon-monoxide monitor and carboxyhaemoglobin estimated from it, with logistic regression adjusted for confounders | F-0880 Pathirathna Impact of solid fuel usage on respiratory symptoms among rep… (2022) | machine |
| Carbon monoxide (CO) | mean 5.27 | reproductive-aged women · home | descriptive cross-sectional study among 403 reproductive-aged women (15 to 49 years) in the Central Province of Sri Lanka: cooking fuel and respiratory symptoms from an interviewer-administered questionnaire, exposure assessed with a breath carbon-monoxide monitor and carboxyhaemoglobin estimated from it, with logistic regression adjusted for confounders | F-0881 Pathirathna Impact of solid fuel usage on respiratory symptoms among rep… (2022) | machine |
| Carbon monoxide (CO) | mean 1.47 | reproductive-aged women · home | descriptive cross-sectional study among 403 reproductive-aged women (15 to 49 years) in the Central Province of Sri Lanka: cooking fuel and respiratory symptoms from an interviewer-administered questionnaire, exposure assessed with a breath carbon-monoxide monitor and carboxyhaemoglobin estimated from it, with logistic regression adjusted for confounders | F-0882 Pathirathna Impact of solid fuel usage on respiratory symptoms among rep… (2022) | machine |
| Carbon monoxide (CO) | mean 4.09 | reproductive-aged women · home | descriptive cross-sectional study among 403 reproductive-aged women (15 to 49 years) in the Central Province of Sri Lanka: cooking fuel and respiratory symptoms from an interviewer-administered questionnaire, exposure assessed with a breath carbon-monoxide monitor and carboxyhaemoglobin estimated from it, with logistic regression adjusted for confounders | F-0883 Pathirathna Impact of solid fuel usage on respiratory symptoms among rep… (2022) | machine |
| Carbon monoxide (CO) | mean 1.29 | reproductive-aged women · home | descriptive cross-sectional study among 403 reproductive-aged women (15 to 49 years) in the Central Province of Sri Lanka: cooking fuel and respiratory symptoms from an interviewer-administered questionnaire, exposure assessed with a breath carbon-monoxide monitor and carboxyhaemoglobin estimated from it, with logistic regression adjusted for confounders | F-0884 Pathirathna Impact of solid fuel usage on respiratory symptoms among rep… (2022) | machine |
| Carbon monoxide (CO) | mean 1.46 | — · home or other indoor setting with smoking | cross-sectional study in Turkey: exhaled carbon monoxide and carboxyhaemoglobin measured in 100 people exposed to passive tobacco smoke indoors, 100 exposed outdoors and a control group, alongside a questionnaire on awareness of passive smoking | F-0919 Evaluation of Exhaled Carbon Monoxide Levels in Individuals … (2023) | machine |
| Carbon monoxide (CO) | mean 1.1 | — · outdoors where smoking took place | cross-sectional study in Turkey: exhaled carbon monoxide and carboxyhaemoglobin measured in 100 people exposed to passive tobacco smoke indoors, 100 exposed outdoors and a control group, alongside a questionnaire on awareness of passive smoking | F-0920 Evaluation of Exhaled Carbon Monoxide Levels in Individuals … (2023) | machine |
| Carbon monoxide (CO) | mean 1.1 | — | cross-sectional study in Turkey: exhaled carbon monoxide and carboxyhaemoglobin measured in 100 people exposed to passive tobacco smoke indoors, 100 exposed outdoors and a control group, alongside a questionnaire on awareness of passive smoking | F-0921 Evaluation of Exhaled Carbon Monoxide Levels in Individuals … (2023) | machine |
| Carbon monoxide (CO) | mean 0.88 | — | cross-sectional study in Turkey: exhaled carbon monoxide and carboxyhaemoglobin measured in 100 people exposed to passive tobacco smoke indoors, 100 exposed outdoors and a control group, alongside a questionnaire on awareness of passive smoking | F-0922 Evaluation of Exhaled Carbon Monoxide Levels in Individuals … (2023) | machine |
| Carbon monoxide (CO) | mean 0.8 | — | cross-sectional study in Turkey: exhaled carbon monoxide and carboxyhaemoglobin measured in 100 people exposed to passive tobacco smoke indoors, 100 exposed outdoors and a control group, alongside a questionnaire on awareness of passive smoking | F-0923 Evaluation of Exhaled Carbon Monoxide Levels in Individuals … (2023) | 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. Exhaled carbon monoxide. Coridum Knowledge G-0119, 16 September 2026. https://coridum.com/k/G-0119/