Source
Natural gas
Also: piped gas, methane, town gas, shale gas, mains gas
Methane delivered by pipe and burned in hobs, ovens, boilers and heaters. Counted as a clean fuel because it produces almost no particles, it remains a combustion source in the room whenever the appliance has no flue.
Where it comes from indoors
What distinguishes natural gas from bottled gas indoors is not the flame but the supply: it arrives continuously, by pipe, so the appliance is never out of fuel and the household never has a reason to fall back on something dirtier.
The flame’s own contribution is nitrogen dioxide, made from the air rather than from the fuel, and it is produced by every gas appliance — the difference between a boiler and a hob being that the boiler sends it up a flue and the hob does not.
Two further points have emerged from recent measurement work. The delivered gas is not pure methane: it carries trace components including benzene and other hydrocarbons, and these enter the room from fittings, from the connection at the appliance, and in the seconds of gas flow before ignition. And a switched-off hob can still leak, so a kitchen has a small continuous source as well as an intermittent one.
What the studies report
| Linked to | Effect | Population | Study design | Source | Checked |
|---|---|---|---|---|---|
| Nitrogen dioxide (NO₂) | difference 47 | households · dwelling | measurement of indoor NO2, CO, formaldehyde and acetaldehyde in 344 homes in four Canadian cities in winter and summer, with mixed models and general linear models relating concentrations to sources and housing characteristics, city-specific and pooled | F-0658 Sun Associations between residential fossil fuel combustion and … (2025) | machine |
| Nitrogen dioxide (NO₂) | difference 54 | households · dwelling | measurement of indoor NO2, CO, formaldehyde and acetaldehyde in 344 homes in four Canadian cities in winter and summer, with mixed models and general linear models relating concentrations to sources and housing characteristics, city-specific and pooled | F-0659 Sun Associations between residential fossil fuel combustion and … (2025) | machine |
| Carbon monoxide (CO) | prevalence 11.70 | residents of Jinan City · dwelling | registry study of non-occupational carbon-monoxide poisoning in Jinan City, Shandong, China, 2007 to 2021: 6588 reported cases from the China Public Health Emergency Information System, with incidence density and mortality per person-year and a spatial comparison of urban and rural districts | F-0792 Li An urgent health problem of indoor air pollution: results fr… (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.
Identifiers
- MeSH
- D059206
Cite this page
Coridum Research. Natural gas. Coridum Knowledge G-0168, 16 September 2026. https://coridum.com/k/G-0168/