Health outcome · disease
COVID-19
Part of: Respiratory infections
Also: coronavirus disease 2019, SARS-CoV-2 infection, covid
The disease caused by the SARS-CoV-2 coronavirus. Its importance in this vocabulary is not clinical: it is the event through which ventilation and air cleaning became building requirements rather than comfort preferences.
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
The pandemic settled an argument that had been open for decades. Once it was accepted that the virus spread through particles suspended in room air, everything about a room became part of its transmission: how much outdoor air it receives, how many people share it, how long they stay, and whether the air is filtered.
The practical legacy is in this vocabulary. Carbon dioxide monitors were installed in classrooms and offices as proxies for shared exhaled air; portable air cleaners were deployed at a scale that finally produced field data on what they achieve in occupied rooms; and ventilation rates that had been guidance became policy.
What the evidence from that period supports and does not support needs care. Studies linking measured ventilation to infection in real buildings are few and observational, and much of what was published rests on modelling rather than on measurement — which Coridum records as such.
Indoor factors with evidence
| Factor | Effect | Population | Study design | Source | Checked |
|---|---|---|---|---|---|
| Nicotine | OR 1.21 (1.01–1.51) | members of multigenerational Tribal households · home | community-engaged cross-sectional study in a Great Plains Tribal community (Cheyenne River Sioux Tribe): 290 multigenerational households, week-long passive monitors for airborne nicotine and nitrogen dioxide, saliva serology for SARS-CoV-2 and a questionnaire on COVID-19 outcomes; multilevel logistic regression grouped by household, adjusted for age, sex, household income and household size | F-0706 Tillery et al. Indoor Air Nicotine, Nitrogen Dioxide Exposure, and COVID-19… (2026) | machine |
| Nitrogen dioxide (NO₂) | OR 3.69 (1.11–16.6) | members of multigenerational Tribal households · home | community-engaged cross-sectional study in a Great Plains Tribal community (Cheyenne River Sioux Tribe): 290 multigenerational households, week-long passive monitors for airborne nicotine and nitrogen dioxide, saliva serology for SARS-CoV-2 and a questionnaire on COVID-19 outcomes; multilevel logistic regression grouped by household, adjusted for age, sex, household income and household size | F-0707 Tillery et al. Indoor Air Nicotine, Nitrogen Dioxide Exposure, and COVID-19… (2026) | 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. COVID-19. Coridum Knowledge G-0182, 16 September 2026. https://coridum.com/k/G-0182/