Health outcome · disease
Respiratory infections
Part of: Respiratory tract diseases
Also: respiratory tract infection, respiratory tract infections, acute respiratory infection, respiratory system infection
Infections of the airways and lungs, from the common cold and sinusitis to bronchiolitis and pneumonia. Indoors they are both transmitted through the air people share and made more likely by what else that air carries.
Not reviewed by a clinician. This entry describes a disease or a symptom. We are introducing clinical review for pages of this kind; until that reviewer is in place, this page has been written and checked by the Coridum team but not reviewed by a clinician. It is general information and not medical advice. How this library is built is described in How we build this library.
Why it matters indoors
Indoor air enters the question twice, and the two routes call for different measures.
The first is transmission. A pathogen leaving one person’s airway travels on particles that stay aloft in a closed room, so the exposure of everyone else depends on how much air that room brings in and how long it holds what is already in it. This is why ventilation belongs to infection as much as to comfort, and why carbon dioxide is read here as a proxy for shared exhaled air rather than as a pollutant in its own right.
The second is susceptibility. Combustion emissions and particulate matter irritate and inflame the airway lining and impair the clearance that removes what lands on it, so the same encounter with a pathogen is more likely to become an illness. Children in homes where cooking and heating happen on an open flame are the population in which this has been measured most often.
Coridum keeps the diagnosis separate from the symptom: a cough recorded in a diary is a respiratory symptom, not an infection.
Indoor factors with evidence
12 of 14 Findings — those with the strongest study design.
| Factor | Effect | Population | Study design | Source | Checked |
|---|---|---|---|---|---|
| Solid fuel | prevalence 13.56 (11.88–15.25) | children under five · home | systematic review and meta-analysis of acute respiratory infection among children under five exposed to indoor air pollution, with subgroup analysis, meta-regression, sensitivity analysis and publication bias tests | F-1513 Indoor air pollution exposure and acute respiratory infectio… (2025) | machine |
| Biomass fuel | ratio 0.54 (0.30–0.98) | infants · home | trial of an improved stove intervention against traditional cooking: incidence of acute respiratory infection in infants followed in both arms, with subgroups by sex and by household size | F-1514 Enyew Impact of improved stove intervention on infant acute respir… (2026) | machine |
| Carbon dioxide (CO₂) | RR 3.17 (1.96–5.17) | — · classroom | study of respiratory virus transmission in school classes: close-range proximity time, shared classroom time and air quality measured against transmission with pairwise accelerated failure time models | F-1506 Banholzer The relative contribution of close-proximity contacts, share… (2025) | machine |
| Tobacco smoke (secondhand smoke) | difference 16 | children · home | analysis of Indian national survey data on acute respiratory illness in children: the illness related to indoor tobacco smoke exposure, to the type of residence, to the age of the child and to the anti-smoking laws in force in the state | F-1338 Verma The association between anti-smoking legislation and prevale… (2024) | machine |
| Ventilation | prevalence 5 per 5 % | college students · dormitory | two-phase study of college dormitories in China: self-reported common cold infections of the students in Phase I and measured outdoor-to-indoor air flow rates per person in the dorm rooms during the heating season in Phase II, related to each other as a dose-response | F-1435 In China, Students in Crowded Dormitories with a Low Ventila… (2011) | machine |
| Ventilation | prevalence 35 per 1 % | college students · dormitory | two-phase study of college dormitories in China: self-reported common cold infections of the students in Phase I and measured outdoor-to-indoor air flow rates per person in the dorm rooms during the heating season in Phase II, related to each other as a dose-response | F-1436 In China, Students in Crowded Dormitories with a Low Ventila… (2011) | machine |
| Ventilation | share-above 90 per 8.3 % | college students · dormitory | two-phase study of college dormitories in China: self-reported common cold infections of the students in Phase I and measured outdoor-to-indoor air flow rates per person in the dorm rooms during the heating season in Phase II, related to each other as a dose-response | F-1437 In China, Students in Crowded Dormitories with a Low Ventila… (2011) | machine |
| Ventilation | difference 2 | college students · dormitory | two-phase study of college dormitories in China: self-reported common cold infections of the students in Phase I and measured outdoor-to-indoor air flow rates per person in the dorm rooms during the heating season in Phase II, related to each other as a dose-response | F-1438 In China, Students in Crowded Dormitories with a Low Ventila… (2011) | machine |
| Solid fuel | OR 3.15 (2.41–4.13) | children under five · home | analysis of Demographic and Health Survey data from Chad: acute respiratory infection in children under five related to the household cooking fuel and to neighbourhood characteristics with multilevel logistic regression | F-1502 Aremu et al. Effect of Household Air Pollution and Neighbourhood Deprivat… (2025) | machine |
| Biomass fuel | prevalence 26.4 | children · home | study of solid biomass fuel use and respiratory health: acute and chronic respiratory infections of women and children compared between households using unimproved and improved cooking fuels | F-1515 Solid Biomass Fuel Use and Respiratory Health Among Women an… (2026) | machine |
| Solid fuel | prevalence 3.3 (3.1–3.4) | children · home | analysis of survey data on acute respiratory infection in children: the prevalence compared between households by cooking fuel, by indoor smoking and by the presence of a separate ventilated kitchen | F-1562 Re-examining the Nexus Between Maternal Smoking Behavior and… (2023) | machine |
| Tobacco smoke (secondhand smoke) | prevalence 3.5 (3.4–3.7) | children · home | analysis of survey data on acute respiratory infection in children: the prevalence compared between households by cooking fuel, by indoor smoking and by the presence of a separate ventilated kitchen | F-1563 Re-examining the Nexus Between Maternal Smoking Behavior and… (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
- D012141
Cite this page
Coridum Research. Respiratory infections. Coridum Knowledge G-0112, 16 September 2026. https://coridum.com/k/G-0112/