Source · category
Indoor fuel combustion
Also: household air pollution, solid fuel use, biomass fuel
Burning fuel inside a dwelling for cooking or heating — wood, coal, charcoal, dung, crop residue, kerosene or gas — with or without a flue. It is the dominant source of indoor particles and combustion gases in households that rely on solid fuels, and a measurable one in kitchens with gas appliances.
Why it matters indoors
Combustion inside a dwelling puts the emission and the person in the same room, which is what separates it from outdoor sources. Particles, carbon monoxide, nitrogen dioxide and a mixture of organic compounds appear together within minutes, at concentrations that depend on the fuel, the appliance and whether anything carries the smoke outside.
What the evidence supports, and what it does not
For respiratory disease and for cardiovascular outcomes the evidence from households using solid fuels is substantial. For skin disease it is weaker than it first appears: a pooled analysis of studies on household fuel use and atopic dermatitis reported a raised odds ratio, but once publication bias was corrected the effect fell close to none — a reminder that a positive pooled estimate is not the same as an established effect.
What the studies report
| Linked to | Effect | Population | Study design | Source | Checked |
|---|---|---|---|---|---|
| Atopic dermatitis (eczema) | OR 1.040 (0.930–1.164) · borderline | — | systematic review and meta-analysis (publication-bias correction) | F-0004 Lang No conclusive link between indoor fuel use and atopic dermat… (2025) | person |
| Atopic dermatitis (eczema) | OR 1.158 (1.051–1.276) | — | systematic review and meta-analysis (publication-bias correction) | F-0003 Lang No conclusive link between indoor fuel use and atopic dermat… (2025) | machine |
| Formaldehyde (CH₂O) | mean 658 | elderly residents of Tujia dwellings · traditional dwelling | field measurements of indoor air quality in traditional Tujia dwellings in Hunan (Zuozi and L-shaped house types) with numerical simulation and mitigation strategies; residents keep open fires by custom | F-0340 Zhang et al. Indoor Air Quality in Tujia Dwellings in Hunan, China: Field… (2022) | machine |
| Respiratory infections | OR 3.6 (1.2–10.1) | — · home | cross-sectional study of 245 households in South Africa: heating and cooking fuel recorded by questionnaire together with dwelling characteristics, and respiratory infections in the household reported over the preceding period | F-1765 Buthelezi et al. Household Fuel Use for Heating and Cooking and Respiratory H… (2019) | 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. The studies are curated in the Coridum Knowledge Base; the reading of them together is a Claim, shown separately.
How strong is the evidence
-
Indoor combustion of household fuels shows no conclusive link with atopic dermatitis: the pooled odds ratio of 1.158 falls to 1.040 once publication bias is corrected.
A Claim is Coridum reading the Findings together, not a quotation from one study — according to Coridum. The grade follows the study designs behind it: A is the strongest, D means a single study or a mechanism.
Frequently asked questions
Does gas cooking count as indoor fuel combustion?
Yes, and it is the form most common in European and Emirati homes. A gas hob without an extractor raises nitrogen dioxide measurably during cooking. The health evidence is strongest for solid fuels used without a flue, which is a different scale of exposure.
How much of the world is exposed?
Household use of solid fuels remains widespread across sub-Saharan Africa and parts of Asia, which is why the World Health Organization treats household air pollution as a leading environmental risk. In homes with electricity or piped gas the exposure is smaller but not absent.
What reduces it most?
Changing the fuel or the appliance beats every other measure — an electric or induction hob removes the source entirely. Where the fuel stays, an extractor vented outside and a flue that works are what separates a manageable exposure from a serious one.
In the literature
- Lang No conclusive link between indoor fuel use and atopic dermatitis: a systematic review and meta-analysis with rigorous publication bias correction (2025). Front Public Health. doi:10.3389/fpubh.2025.1672618 CKB 1424
- Solid Biomass Fuel Use and Respiratory Health Among Women and Children in South Asian… (2026). Cureus. doi:10.7759/cureus.104012 CKB 1552
- Insights into household air pollution: A systematic scoping review on perceptions of solid biomass fuel use in South Asian countries (2025). J Family Med Prim Care. doi:10.4103/jfmpc.jfmpc_1817_24 CKB 1413
Studies in the Coridum Knowledge Base in which this term is used. The definition follows standard usage in WHO, ISO and textbook sources; it is not quoted from these papers.
CKB = document number in the Coridum Knowledge Base, our curated library of peer-reviewed studies. Follow the DOI for the original paper.
Cite this page
Coridum Research. Indoor fuel combustion. Coridum Knowledge G-0093, 16 September 2026. https://coridum.com/k/G-0093/