Wildfire smoke raises health risks far from fire zones, experts say

Smoke from wildfires can create health risks for people near the flames and farther away when winds carry pollution, according to French health agency Anses and French pulmonologist Bruno Crestani.

Anses said fires burning vegetation release gases and airborne particles that can harm the body. It said fine particles are especially dangerous because they can go deep into the lungs. The agency said carbon monoxide is one of the main pollutants released by such fires, along with carbon dioxide and volatile organic compounds including acrolein, formaldehyde and benzene. If vehicles or buildings burn, other pollutants can also mix into the smoke.

Crestani said people closest to a fire can show signs of respiratory irritation. He said wider effects can appear over the following hours or several days if wind carries smoke. He said older people, infants, people with respiratory disease and people with asthma are especially vulnerable because smoke can destabilise a condition that had previously been under control.

Crestani said the impact is not only respiratory. He said fine particles can enter the circulatory system and may trigger diabetes, a stroke or a heart attack. He also said the particles are light enough to travel long distances and affect people far from the fire zone.

The World Meteorological Organization said in September 2025 that wildfires can send a toxic mix of pollutants thousands of kilometres. It said smoke from Canadian wildfires in 2024 caused air pollution as far away as Europe.

Anses said firefighters face exposure not only while fighting fires, but also while monitoring extinguished areas, investigating, clearing sites and returning to fire stations with contaminated equipment and vehicles. The agency said smoke inhalation, heat stress, dehydration, strenuous work, sleep deprivation, accumulated fatigue and accidents can increase their vulnerability.

The medical journal The Lancet estimated in December 2025 that exposure to wildfire smoke led to an estimated 154,000 deaths worldwide the previous year, attributed to fine particulate matter. For France, Oxfam estimated 2,800 early deaths each year from air pollution caused by wildfires.

French Prime Minister Sebastien Lecornu promised to send 1.5 million FFP2 masks to the Gironde region, where an unprecedented wildfire was burning, to help protect residents. Anses recommends such masks for people likely to have health difficulties when exposed to smoke and advises people with breathing problems or other symptoms to seek medical help. Crestani said masks do not give complete protection but are useful.

In areas that have not been evacuated, Anses advised people to limit time outdoors and keep windows and doors closed. It also advised placing wet cloths in front of air vents and turning off automatic bathroom ventilation.