Wildfire smoke in Europe linked to higher short-term mortality, study finds

Research highlights mortality risks from wildfire smoke

The Lancet – Planetary Health has published a study showing that wildfire smoke increases short-term mortality across Europe, with respiratory deaths most affected.

The study analysed daily mortality records from 654 regions across 32 countries between 2004 and 2022, covering a population of 541 million people.

Researchers found that fine particulate matter (PM2.5) from wildfire smoke carried greater health risks than PM2.5 from other sources.

Relative risks for cardiovascular and respiratory deaths were higher when linked specifically to wildfire smoke, with respiratory mortality showing the strongest association.

The authors concluded that previous studies underestimated the health burden of wildfire smoke when treating it as equivalent to other types of particulate pollution.

Methodology and dataset explained

The study used the EARLY-ADAPT database to obtain mortality records alongside PM2.5 exposure estimates from the SILAM atmospheric model.

The dataset included more than 95 million daily all-cause deaths, nearly 20 million cardiovascular deaths, and almost 4 million respiratory deaths recorded during the study period.

Associations were calculated using quasi-Poisson regression, assessing the impact of incremental increases in wildfire-related PM2.5.

The researchers noted that fire-related PM2.5 exposure led to stronger mortality associations compared with non-fire sources of PM2.5.

The analysis indicated that using general PM2.5 measures underestimated deaths from wildfire smoke by as much as 93 per cent.

Findings on mortality associations

The study reported that pooled results showed a relative risk of 1.007 for all-cause mortality, 1.009 for cardiovascular mortality, and 1.013 for respiratory mortality per 1 μg/m³ increase in wildfire PM2.5.

The team found that respiratory mortality was particularly sensitive to wildfire-related particles compared with other causes.

Comparisons with previous studies showed similar patterns in France, Italy and Romania, where risk estimates aligned with global datasets.

The researchers suggested that higher toxicity, oxidative potential, and exposure intensity during wildfire events could explain the stronger associations.

Wildfire smoke exposure was described as distinct from background pollution, with periods of very high exposure followed by little to none, unlike continuous urban air pollution.

Climate change and wildfire exposure

The analysis explained that climate change is a key driver of wildfire frequency and intensity across Europe.

Estimates suggest burned areas in Europe could rise by 200 per cent this century if no adaptation measures are introduced.

Even moderate climate change scenarios predict major increases in catastrophic fire risk in southern Europe, with central and northern Europe also becoming more vulnerable during droughts.

Human activity was identified as the cause of 96 per cent of wildfire ignitions in Europe, but weather, vegetation and topography determined fire spread.

The researchers linked climate change, wildfire spread, and smoke exposure in a feedback loop, with each element amplifying the others.

Regional variations in effects

The study indicated that health impacts varied across European regions.

For Portugal and Spain, associations between wildfire smoke and mortality were weaker or imprecise, which researchers said might reflect fire management strategies or adaptation efforts.

Rural populations were reported to be more heavily exposed than urban populations because of their proximity to wildfire sources.

The analysis found that mortality risks were consistent even when accounting for additional pollutants such as ozone.

However, it noted that disentangling the independent effects of wildfire smoke and ozone remains an area requiring further research.

Strengths and limitations of the study

The researchers highlighted that the multicountry dataset provided comprehensive coverage across urban and rural populations.

The SILAM model allowed the team to distinguish wildfire-related PM2.5 from other sources, supporting direct comparison between exposure types.

Limitations included reduced statistical power in estimating risks by age or sex, as fire-related PM2.5 exposure was less variable than general pollution.

Mortality data availability differed by country, which limited subnational analysis in certain areas.

The study added that exposure misclassification could not be fully ruled out and may have led to underestimates of health effects.

Relevance for fire and safety professionals

The findings demonstrate the direct public health burden linked to wildfire smoke exposure across Europe.

Fire and safety professionals may need to factor air quality impacts into wildfire risk management and community protection strategies.

Emergency planning, firefighter safety, and post-fire recovery measures can benefit from understanding the mortality risks linked to smoke exposure.

The research also reinforces the importance of considering climate change as a driver of future wildfire hazards in Europe.

Wildfire smoke in Europe linked to higher short-term mortality, study finds: Summary

The Lancet – Planetary Health reported that wildfire smoke is linked to increased short-term mortality in Europe.

The study used data from 654 regions in 32 countries, covering 541 million people.

Researchers found that fine particulate matter (PM2.5) from wildfire smoke had higher relative risks for mortality than PM2.5 from other sources.

Respiratory deaths showed the strongest association with wildfire smoke exposure.

All-cause mortality risk increased by 0.7 per cent per 1 μg/m³ increase in fire-related PM2.5.

Cardiovascular mortality risk increased by 0.9 per cent under the same conditions.

Respiratory mortality risk increased by 1.3 per cent for the same increment.

Using total PM2.5 underestimated wildfire-related deaths by 93 per cent.

The analysis covered daily mortality records from 2004 to 2022.

The SILAM atmospheric model was used to estimate PM2.5 sources and levels.

Rural populations were more heavily exposed than urban populations.

Regional variations were observed, with weaker associations in Portugal and Spain.

The researchers linked climate change to increased wildfire risk in Europe.

They said wildfires in Europe are 96 per cent human-caused in origin.

They noted climate change amplifies wildfire size, duration and spread.

The dataset included more than 95 million daily all-cause deaths.

It also recorded nearly 20 million cardiovascular and 4 million respiratory deaths.

The research indicated stronger effects for respiratory outcomes compared with other mortality causes.

The authors said estimates of wildfire smoke health burdens should be based on fire-specific data.