Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (707 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
Fires that occur outdoors in the natural environment caused by natural forces or human activity.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Wildfire; Wild Fires; Fires, Wild; Fire, Wild; Wild Fire; Wildland Fires; Fires, Wildland; Forest Fires.
Where it fits in the MeSH classification
- Broader topics
- Ecological and Environmental Phenomena; Natural Disasters; Fires
Research landscape
PubMed indexes 2,319 records tagged with the MeSH heading “Wildfires” (counts retrieved 2026-10-31). 1,983 of them (85.5%) were published from 2020 onward, and the busiest period so far is 2020 onward with 1,983 records.
Reviews account for 188 records (8.1%) and meta-analyses for 20. Randomized controlled trials number 4 (0.2%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 0 |
| 2000-2009 | 0 |
| 2010-2019 | 352 |
| 2020 onward | 1,983 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 188 | 8.1% |
| Meta-analyses | 20 | 0.9% |
| Randomized controlled trials | 4 | 0.2% |
Method: PubMed query "Wildfires"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in public health and nutrition
Population and nutrition studies mostly observe what people eat, breathe or are exposed to and then look for links with health, which shows association and not proof of cause. Self-reported diet is imprecise, people who eat or live differently also differ in other ways, and effects measured across a population may not apply to one person. Check the study design, how exposure was measured, what else was accounted for and the size of the effect, not only whether it was statistically significant.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Carbon emissions from the 2023 Canadian wildfires | 2024 | Research article Design not recorded in structured metadata | 49 | cc by PMID 39198654 · DOI · PMC11424480 |
| Metal toxin threat in wildland fires determined by geology and fire severity | 2023 | Research article Design not recorded in structured metadata | 33 | cc by PMID 38086795 · DOI · PMC10716285 |
| Forest fire size amplifies postfire land surface warming | 2024 | Research article Design not recorded in structured metadata | 24 | cc by PMID 39322733 · DOI · PMC11424489 |
| Cardiopulmonary hospitalization risks from wildfire-specific and non-wildfire PM2.5 in 20 US states | 2026 | Research article Design not recorded in structured metadata | 1 | cc by PMID 42754610 · DOI · PMC13586224 |
Carbon emissions from the 2023 Canadian wildfires [1]
Abstract reading summary — source excerpts
- Opening excerpt
- The 2023 Canadian forest fires have been extreme in scale and intensity with more than seven times the average annual area burned compared to the previous four decades1.
- Closing excerpt
- Such conditions are likely to drive increased fire activity and suppress carbon uptake by Canadian forests, adding to concerns about the long-term durability of these forests as a carbon sink5-8.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (179 words)
The 2023 Canadian forest fires have been extreme in scale and intensity with more than seven times the average annual area burned compared to the previous four decades1. Here, we quantify the carbon emissions from these fires from May to September 2023 on the basis of inverse modelling of satellite carbon monoxide observations. We find that the magnitude of the carbon emissions is 647 TgC (570-727 TgC), comparable to the annual fossil fuel emissions of large nations, with only India, China and the USA releasing more carbon per year2. We find that widespread hot-dry weather was a principal driver of fire spread, with 2023 being the warmest and driest year since at least 19803. Although temperatures were extreme relative to the historical record, climate projections indicate that these temperatures are likely to be typical during the 2050s, even under a moderate climate mitigation scenario (shared socioeconomic pathway, SSP 2-4.5)4. Such conditions are likely to drive increased fire activity and suppress carbon uptake by Canadian forests, adding to concerns about the long-term durability of these forests as a carbon sink5-8.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 39198654 · DOI · PMC11424480
Metal toxin threat in wildland fires determined by geology and fire severity [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Accentuated by climate change, catastrophic wildfires are a growing, distributed global public health risk from inhalation of smoke and dust.
- Closing excerpt
- Our findings provide new insights into why wildfire smoke exposure appears to be more hazardous to humans than pollution from other sources.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (152 words)
Accentuated by climate change, catastrophic wildfires are a growing, distributed global public health risk from inhalation of smoke and dust. Underrecognized, however, are the health threats arising from fire-altered toxic metals natural to soils and plants. Here, we demonstrate that high temperatures during California wildfires catalyzed widespread transformation of chromium to its carcinogenic form in soil and ash, as hexavalent chromium, particularly in areas with metal-rich geologies (e.g., serpentinite). In wildfire ash, we observed dangerous levels (327-13,100 µg kg-1) of reactive hexavalent chromium in wind-dispersible particulates. Relatively dry post-fire weather contributed to the persistence of elevated hexavalent chromium in surficial soil layers for up to ten months post-fire. The geographic distribution of metal-rich soils and fire incidents illustrate the broad global threat of wildfire smoke- and dust-born metals to populations. Our findings provide new insights into why wildfire smoke exposure appears to be more hazardous to humans than pollution from other sources.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 38086795 · DOI · PMC10716285
Forest fire size amplifies postfire land surface warming [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Climate warming has caused a widespread increase in extreme fire weather, making forest fires longer-lived and larger1-3.
- Closing excerpt
- Given the projected increase in fire size in northern forests14,15, climate-smart forestry should aim to mitigate the climate risks of large fires, possibly by increasing the share of broadleaf trees, where appropriate, and avoiding active pyrophytes.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (199 words)
Climate warming has caused a widespread increase in extreme fire weather, making forest fires longer-lived and larger1-3. The average forest fire size in Canada, the USA and Australia has doubled or even tripled in recent decades4,5. In return, forest fires feed back to climate by modulating land-atmospheric carbon, nitrogen, aerosol, energy and water fluxes6-8. However, the surface climate impacts of increasingly large fires and their implications for land management remain to be established. Here we use satellite observations to show that in temperate and boreal forests in the Northern Hemisphere, fire size persistently amplified decade-long postfire land surface warming in summer per unit burnt area. Both warming and its amplification with fire size were found to diminish with an increasing abundance of broadleaf trees, consistent with their lower fire vulnerability compared with coniferous species9,10. Fire-size-enhanced warming may affect the success and composition of postfire stand regeneration11,12 as well as permafrost degradation13, presenting previously overlooked, additional feedback effects to future climate and fire dynamics. Given the projected increase in fire size in northern forests14,15, climate-smart forestry should aim to mitigate the climate risks of large fires, possibly by increasing the share of broadleaf trees, where appropriate, and avoiding active pyrophytes.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 39322733 · DOI · PMC11424489
Cardiopulmonary hospitalization risks from wildfire-specific and non-wildfire PM2.5 in 20 US states [4]
Abstract reading summary — source excerpts
- Opening excerpt
- Increasing wildfire activity in the US has made wildfire-specific fine particulate matter (PM2.
- Closing excerpt
- 5, underscoring wildfire smoke as a growing public health threat that requires targeted mitigation alongside conventional air quality control strategies.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (177 words)
Increasing wildfire activity in the US has made wildfire-specific fine particulate matter (PM2.5) an important and growing source of air pollution, yet its long-term health impacts and relative toxicity compared with non-wildfire PM2.5 remain unclear. Using a self-controlled design, we examine associations between 2-year average wildfire-specific and non-wildfire PM2.5 and cardiopulmonary hospitalization risks across 20 US states during 2006-2019. Per 1 µg/m3 increase, wildfire-specific PM2.5 is associated with significantly higher hospitalization risks for all cardiopulmonary diseases, with relative risks ranging from 10% for heart failure to 16% for asthma. In contrast, a 1-µg/m3 increase in non-wildfire PM2.5 is associated with smaller risk elevations, ranging from 4.7% for chronic obstructive pulmonary disease to 8.5% for hypertension. Stronger associations for both wildfire-specific and non-wildfire PM2.5 are observed among minorities, metropolitan residents, those with fewer years of education, and more deprived communities. Overall, at an equivalent concentration increase, long-term exposure to wildfire-specific PM2.5 poses greater cardiopulmonary hospitalization risks than non-wildfire PM2.5, underscoring wildfire smoke as a growing public health threat that requires targeted mitigation alongside conventional air quality control strategies.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42754610 · DOI · PMC13586224
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Wildland fire smoke and human health [5]
- Research article Mortality risk attributable to wildfire-related PM2·5 pollution: a global time series study in 749 locations [6]
- Research article Wildfire smoke exposure and human health: Significant gaps in research for a growing public health issue [7]
- Research article Global climate change and mental health [8]
- Research article Fire and biodiversity in the Anthropocene [9]
- Research article Cardiovascular health impacts of wildfire smoke exposure [10]
References
- Byrne B, Liu J, Bowman KW, Pascolini-Campbell M, Chatterjee A, Pandey S, et al.. Carbon emissions from the 2023 Canadian wildfires. . 2024. PMID 39198654 · DOI · PMC11424480
- Lopez AM, Pacheco JL, Fendorf S. Metal toxin threat in wildland fires determined by geology and fire severity. . 2023. PMID 38086795 · DOI · PMC10716285
- Zhao J, Yue C, Wang J, Hantson S, Wang X, He B, et al.. Forest fire size amplifies postfire land surface warming. . 2024. PMID 39322733 · DOI · PMC11424489
- Zhang M, Castro E, Qiu M, Danesh Yazdi M, Li B, Wright RJ, et al.. Cardiopulmonary hospitalization risks from wildfire-specific and non-wildfire PM2.5 in 20 US states. . 2026. PMID 42754610 · DOI · PMC13586224
- Cascio WE. Wildland fire smoke and human health. Sci Total Environ. 2018. PMID 29272827 · DOI · PMC6697173
- Chen G, Guo Y, Yue X, Tong S, Gasparrini A, Bell ML, et al.. Mortality risk attributable to wildfire-related PM2·5 pollution: a global time series study in 749 locations. Lancet Planet Health. 2021. PMID 34508679 · DOI
- Black C, Tesfaigzi Y, Bassein JA, Miller LA. Wildfire smoke exposure and human health: Significant gaps in research for a growing public health issue. Environ Toxicol Pharmacol. 2017. PMID 28892756 · DOI · PMC5628149
- Palinkas LA, Wong M. Global climate change and mental health. Curr Opin Psychol. 2020. PMID 31349129 · DOI
- Kelly LT, Giljohann KM, Duane A, Aquilué N, Archibald S, Batllori E, et al.. Fire and biodiversity in the Anthropocene. Science. 2020. PMID 33214246 · DOI
- Chen H, Samet JM, Bromberg PA, Tong H. Cardiovascular health impacts of wildfire smoke exposure. Part Fibre Toxicol. 2021. PMID 33413506 · DOI · PMC7791832
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-11-04; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-11-04.
See how EvidenceLib is built. Spotted an error? Email support@evidencehelix.com.
Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.