Source · category
Wildfire smoke
Also: wildfire, bushfire smoke, forest fire smoke, landscape fire smoke, smoke event
The mixture of particles and gases from burning vegetation and, where fires reach settlements, from burning buildings and their contents. It is an outdoor event that becomes an indoor exposure, because smoke enters every building that is not sealed against it.
Where it comes from indoors
Wildfire smoke is the one major exposure in this vocabulary that no household action creates and none can prevent. What a household can change is how much of it gets in, and how much of what gets in stays.
Indoor concentrations during a smoke episode are set by infiltration: the fraction of outdoor particulate matter that survives the journey through the building envelope. A tight, closed house holds a fraction of the outdoor level; a leaky one holds most of it; and the same house is a refuge on a smoky day and a trap on the day after, when outdoor air has cleared and indoor air has not.
Two further features distinguish it from steady urban pollution. Episodes are short and extreme, so exposure is measured in days rather than years; and smoke from a fire that burned houses carries what those houses contained.
What the studies report
12 of 13 Findings — those with the strongest study design.
| Linked to | Effect | Population | Study design | Source | Checked |
|---|---|---|---|---|---|
| Particulate matter (PM₂.₅ and PM₁₀) | difference 3.83 (0.22–7.44) | — | panel study relating wildfire days to blood pressure: systolic and diastolic pressure of the participants compared between survey periods with and without wildfire days, and against the fine particulate matter of those periods | F-1482 Walker et al. Associations between fine particulate matter and in-home blo… (2025) | machine |
| Particulate matter (PM₂.₅ and PM₁₀) | difference 2.36 (-0.06–4.78) · borderline | — | panel study relating wildfire days to blood pressure: systolic and diastolic pressure of the participants compared between survey periods with and without wildfire days, and against the fine particulate matter of those periods | F-1483 Walker et al. Associations between fine particulate matter and in-home blo… (2025) | machine |
| Particulate matter (PM₂.₅ and PM₁₀) | mean 18.98 | — · home | study of do-it-yourself air cleaners in homes: indoor and outdoor fine particulate matter measured in phases during a wildfire season and during a wintertime wood stove season, with the infiltrated indoor fraction separated | F-1484 Turner Self-reported health impacts of do-it-yourself air cleaner u… (2024) | machine |
| Particulate matter (PM₂.₅ and PM₁₀) | mean 10.89 | — · home | study of do-it-yourself air cleaners in homes: indoor and outdoor fine particulate matter measured in phases during a wildfire season and during a wintertime wood stove season, with the infiltrated indoor fraction separated | F-1485 Turner Self-reported health impacts of do-it-yourself air cleaner u… (2024) | machine |
| Particulate matter (PM₂.₅ and PM₁₀) | other 0.30 (0.21–0.43) | — · laboratory animal facility | indoor air quality study of a laboratory animal facility: fine particulate matter measured in the room and inside a cage with a high efficiency particulate air filter, indoors and outdoors, on wildfire and non-wildfire days, with the infiltration factor estimated | F-1486 Schuller et al. Indoor Air Quality Considerations for Laboratory Animals in … (2022) | machine |
| Particulate matter (PM₂.₅ and PM₁₀) | mean 162 | pregnant women · home | study of wildfire smoke infiltration and the exposure of pregnant women: indoor, outdoor and personal fine particulate matter measured with a sensor network and personal samplers in the wildfire season and in the non-wildfire season | F-1478 Ardiyani The infiltration of wildfire smoke and its potential dose on… (2023) | machine |
| Particulate matter (PM₂.₅ and PM₁₀) | mean 187 | pregnant women · outdoors at the homes | study of wildfire smoke infiltration and the exposure of pregnant women: indoor, outdoor and personal fine particulate matter measured with a sensor network and personal samplers in the wildfire season and in the non-wildfire season | F-1479 Ardiyani The infiltration of wildfire smoke and its potential dose on… (2023) | machine |
| Particulate matter (PM₂.₅ and PM₁₀) | mean 61 | pregnant women · home | study of wildfire smoke infiltration and the exposure of pregnant women: indoor, outdoor and personal fine particulate matter measured with a sensor network and personal samplers in the wildfire season and in the non-wildfire season | F-1480 Ardiyani The infiltration of wildfire smoke and its potential dose on… (2023) | machine |
| Particulate matter (PM₂.₅ and PM₁₀) | mean 58 | pregnant women · outdoors at the homes | study of wildfire smoke infiltration and the exposure of pregnant women: indoor, outdoor and personal fine particulate matter measured with a sensor network and personal samplers in the wildfire season and in the non-wildfire season | F-1481 Ardiyani The infiltration of wildfire smoke and its potential dose on… (2023) | machine |
| — | prevalence 41.7 | — · home | survey during a wildfire episode: reported health symptoms and perceived indoor air quality of the respondents, related to the wildfire smoke concentration by a mediation model | F-1487 Lee et al. Wildfire smoke-related PM2.5 concentration measurements, per… (2026) | machine |
| Polycyclic aromatic hydrocarbons | share-above 58 | — · home | study of polycyclic aromatic hydrocarbons indoors and outdoors during and outside wildfire episodes, with silicone passive samplers at several locations and the air quality index recorded | F-1488 Wildfire Impact on Indoor and Outdoor PAH Air Quality (2022) | machine |
| Volatile organic compounds (VOCs) | other 20 | — · home | field measurement campaign in homes affected by a wildland-urban interface fire: volatile organic compounds measured indoors by proton-transfer-reaction time-of-flight mass spectrometry over the weeks following the fire, with mitigation tests using activated-carbon air cleaners and window opening | F-1586 Volatile Organic Compounds Inside Homes Impacted by Smoke fr… (2025) | 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. Wildfire smoke. Coridum Knowledge G-0122, 16 September 2026. https://coridum.com/k/G-0122/