Wildfires and heatwaves threaten air quality and public health, UN warns

Monday 07 September 2026 - 17:30

By: Azzat Manal

Wildfires and heatwaves threaten air quality and public health, UN warns

Wildfires and extreme heat are creating a growing threat to air quality and public health, with microscopic pollutants released into the atmosphere capable of affecting people and ecosystems far beyond the areas directly hit by fires, the World Meteorological Organization (WMO) has warned.

In its latest Air Quality and Climate Bulletin, the UN weather and climate agency highlighted the close relationship between climate change and air pollution. Rising global temperatures are contributing to more frequent and intense heatwaves and wildfires, while the resulting pollution can further worsen environmental and health conditions.

One of the main concerns is fine particulate matter known as PM2.5. These particles are less than 2.5 micrometres in diameter and can penetrate deep into the respiratory system and enter the bloodstream, increasing the risk of serious health problems. Although PM2.5 is also produced by transport, industry, agriculture and household heating, wildfire smoke has become an increasingly important source.

The WMO stressed that particles released by burning vegetation can be particularly toxic. Carried by winds, wildfire smoke can travel hundreds or even thousands of kilometres, exposing populations and wildlife far from the original fire. The organisation warned that conventional assessments based on overall PM2.5 concentrations may significantly underestimate deaths linked specifically to wildfire smoke.

Research cited in the WMO report indicates that extreme wildfire-smoke events have increased substantially since the 1990s. Between 2010 and 2018, such pollution was associated with nearly 100,000 additional deaths annually, although researchers believe the actual impact could be even greater.

Lorenzo Labrador of the WMO’s Global Atmosphere Watch network said air quality and climate change should not be treated as separate challenges. Areas affected by major forest fires can experience extremely high concentrations of fine particles, creating health risks for populations both near and far from the fires.

Heatwaves pose another major air-quality threat through ground-level ozone. This pollutant can build up when temperatures are high, atmospheric circulation is weak and sunlight is intense. Recent heatwaves in regions including China, Europe and the southeastern United States have highlighted the potential health consequences of increased ozone exposure, particularly for people vulnerable to respiratory illnesses.

The WMO is also calling for improved monitoring of a wider range of airborne pollutants, including aerosols, black carbon, microplastics, fine particles and ground-level ozone. Many of these pollutants are widespread but remain insufficiently measured, despite their potential effects on human health and ecosystems.

Aerosols can travel across borders and oceans, influencing atmospheric conditions and changing the way sunlight interacts with the Earth. Black carbon, for example, can settle on snow and ice, reducing their ability to reflect sunlight and potentially accelerating melting.

Microplastics are another emerging concern. As plastic waste breaks down through sunlight and other environmental processes, tiny particles can become airborne and circulate through the atmosphere. According to a simulation cited by the WMO, tens of millions of tonnes of microplastics are present on land and in the oceans, creating potential sources for atmospheric contamination.

The UN agency is therefore urging governments to coordinate climate and air-quality policies rather than addressing the two issues separately. Better monitoring, stronger pollution controls and climate action could help reduce the combined risks posed by extreme heat, wildfires and atmospheric pollution.