Health outcome · symptom
Wheeze
Also: wheezing, recurrent wheeze
A high-pitched whistling sound made during breathing, usually on breathing out, caused by air moving through narrowed airways. It is a symptom, not a diagnosis: it occurs in asthma, in infections and in other conditions, and in young children it often occurs without either.
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
Wheeze is the symptom that indoor exposure studies in children most often measure, for two reasons: parents notice and report it reliably, and it appears earlier than any diagnosis. Studies distinguish recurrent wheeze — repeated episodes — from ever wheeze, and often from wheeze treated with inhaled corticosteroids, because those describe different degrees of severity and are not interchangeable.
Reading a study about wheeze as if it were a study about asthma is the commonest error in this literature. Many children who wheeze never develop asthma, and the association of an indoor exposure with wheeze does not establish that it causes asthma.
What helps
The evidence Coridum holds concerns which indoor exposures are associated with wheeze, not which measures reduce it. No intervention study is currently in the library for this symptom, and no claim about what helps is made here. Where the associated compounds have a known indoor source — cleaning products, personal care products, renovation — source control and ventilation are the general levers, but that is reasoning from the source, not evidence about the symptom.
What to measure
Wheeze itself is recorded by a clinician or by a validated parental questionnaire, not by a sensor. What can be measured in the room are the exposures the studies associate with it: total volatile organic compounds, and where a laboratory analysis is available, the individual compounds those studies name.
Indoor factors with evidence
12 of 21 Findings — those with the strongest study design.
| Factor | Effect | Population | Study design | Source | Checked |
|---|---|---|---|---|---|
| Nitrogen dioxide (NO₂) | OR 1.38 (1.04–1.83) | school children · classroom | double-blind, cluster-randomised crossover trial in Australian school classrooms: low-NOx unflued gas heaters against non-indoor-emitting flued gas heaters, NO2 and formaldehyde measured with passive diffusion badges, children recorded symptoms, medication use and lung function twice daily | F-0692 Respiratory Health Effects of Exposure to Low-NOx Unflued Ga… (2010) | machine |
| Nitrogen dioxide (NO₂) | OR 1.41 (1.05–1.90) | persons living with HIV and persons at risk for HIV · home | Baltimore cohort of persons living with HIV and persons at risk for HIV (SHIELD): 1997 participants with baseline questionnaires and spirometry for reported household exposures, plus a 36-home pilot (SHIELD Home) with weeklong direct measurement of household PM2.5 and NO2; logistic and quantile regression adjusted for age, sex, smoking, race, HIV serostatus and lung function | F-0700 Unraveling the impact of indoor air pollution on respiratory… (2025) | machine |
| Cleaning products | OR 1.22 (1.00–1.47) · borderline | — · home | birth cohort analysis of indoor volatile organic compound concentrations and wheezing in children: the measured compounds were reduced to factors and each factor related to ever wheeze, ever wheeze with inhaled corticosteroids and recurrent wheeze by logistic regression | F-1365 Association between volatile organic compound concentrations… (2026) | machine |
| Carbon dioxide (CO₂) | OR 1.20 per 100 ppm | office workers · office | cross-sectional analysis of the 100-building 1994-1998 USEPA BASE office dataset: workday time-averaged indoor minus outdoor CO2 (dCO2) against sick building syndrome symptoms, multivariate logistic regression adjusted for age, sex, smoking, carpet, thermal exposure and a marker of entrained automobile exhaust | F-0394 Indoor carbon dioxide concentrations and sick building syndr… (2002) | machine |
| Carbon monoxide (CO) | OR 0.47 (0.26–0.87) | 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-0877 Pathirathna Impact of solid fuel usage on respiratory symptoms among rep… (2022) | machine |
| Carbon monoxide (CO) | OR 5.78 (1.62–20.70) | preschool children · kindergarten classroom | cross-sectional study of indoor air quality and respiratory health in preschools in Selangor, Malaysia: PM2.5, carbon monoxide and carbon dioxide measured in classrooms of an industrial study area and of a comparative area, with symptom questionnaires and spirometry among Malay preschool children | F-0933 Indoor Air Quality and Respiratory Health among Malay Presch… (2015) | machine |
| — | prevalence 8.4 | pupils aged 11 to 15 · classroom | cross-sectional study in a coal-burning city in northern China: a questionnaire on respiratory health and home environment was answered by 1,993 pupils aged 11 to 15 in ten urban schools of Taiyuan, and indoor and outdoor air pollutants and climate factors were measured in the same schools in winter | F-1289 Lotz Asthmatic Symptoms among Pupils in Relation to Winter Indoor… (2008) | machine |
| Sulfur dioxide (SO₂) | a stated direction without a coefficient; the sentence names the three pollutants together and ozone is not among them | pupils aged 11 to 15 · classroom | cross-sectional study in a coal-burning city in northern China: a questionnaire on respiratory health and home environment was answered by 1,993 pupils aged 11 to 15 in ten urban schools of Taiyuan, and indoor and outdoor air pollutants and climate factors were measured in the same schools in winter | F-1291 Lotz Asthmatic Symptoms among Pupils in Relation to Winter Indoor… (2008) | machine |
| Nitrogen dioxide (NO₂) | a stated direction without a coefficient; the sentence names the three pollutants together and ozone is not among them | pupils aged 11 to 15 · classroom | cross-sectional study in a coal-burning city in northern China: a questionnaire on respiratory health and home environment was answered by 1,993 pupils aged 11 to 15 in ten urban schools of Taiyuan, and indoor and outdoor air pollutants and climate factors were measured in the same schools in winter | F-1292 Lotz Asthmatic Symptoms among Pupils in Relation to Winter Indoor… (2008) | machine |
| Formaldehyde (CH₂O) | a stated direction without a coefficient; the sentence names the three pollutants together and ozone is not among them | pupils aged 11 to 15 · classroom | cross-sectional study in a coal-burning city in northern China: a questionnaire on respiratory health and home environment was answered by 1,993 pupils aged 11 to 15 in ten urban schools of Taiyuan, and indoor and outdoor air pollutants and climate factors were measured in the same schools in winter | F-1293 Lotz Asthmatic Symptoms among Pupils in Relation to Winter Indoor… (2008) | machine |
| Coal | OR 1.57 (1.07–2.29) | seventh-grade pupils · home | cross-sectional study of 5051 seventh-grade pupils in 22 randomly selected schools of the greater metropolitan area of Wuhan, China: a self-administered in-class questionnaire on respiratory health and the home environment, analysed with logistic regression | F-1321 Respiratory symptoms in relation to residential coal burning… (2004) | machine |
| Coal | OR 1.44 (1.05–1.97) | seventh-grade pupils · home | cross-sectional study of 5051 seventh-grade pupils in 22 randomly selected schools of the greater metropolitan area of Wuhan, China: a self-administered in-class questionnaire on respiratory health and the home environment, analysed with logistic regression | F-1322 Respiratory symptoms in relation to residential coal burning… (2004) | 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.
How strong is the evidence
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In children attending daycare, a single French study suggests that higher indoor concentrations of two solvents — methyl isobutyl ketone and 1-methoxy-2-propyl acetate — go together with recurrent wheeze; for two further compounds the association did not survive correction for multiple testing.
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.
In the literature
- Association between volatile organic compound concentrations in daycares and child wheeze: the French CRESPI study (2026). Environ Health. doi:10.1186/s12940-026-01307-6 CKB 1230
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. Wheeze. Coridum Knowledge G-0105, 16 September 2026. https://coridum.com/k/G-0105/