Wildfires threaten air quality gains

For decades, various policies have been implemented in Europe and North America to reduce air pollution caused by industry, transportation, and fuel use. These measures have contributed to a reduction in fine particulate matter pollution in many regions.
However, a new risk is growing: wildfire smoke.
*Air Quality and Climate Bulletin No. 6*, published by the World Meteorological Organization (WMO) on September 7, 2026, shows that the link between climate change and air pollution is becoming increasingly evident.
According to the report, pollution caused by heatwaves and wildfires threatens the gains made in improving air quality. The WMO emphasizes that climate policies and air quality policies can no longer be treated separately.

Extreme fire and smoke events have tripled
One of the report's most striking findings concerns long-term changes in wildfire smoke.
Research cited by the WMO indicates that the frequency of extreme fire and smoke events worldwide has roughly tripled since the 1990s.
The same study estimates that these events were associated with approximately 100,000 additional deaths annually worldwide during the 2010–2018 period.
This situation could become even more critical in the future. As climate change intensifies heatwaves and weather conditions conducive to wildfires, achieving the World Health Organization’s air quality targets may become increasingly difficult.

The invisible component of wildfire smoke: PM2.5
One of the significant health risks associated with wildfire smoke is fine particulate matter, known as PM2.5. These particles, with a diameter of less than 2.5 micrometers, can penetrate deep into the respiratory system. Exposure to PM2.5 is linked to various health issues, particularly respiratory and cardiovascular diseases.
However, assessing the impact of wildfire smoke solely based on the total quantity of PM2.5 may not be sufficient.
A scientific study cited by the WMO indicates that traditional risk models may underestimate the mortality burden associated with wildfires by as much as 93 percent. One reason for this is that the composition and toxicity of wildfire-generated particles can differ from those of other PM2.5 sources.
This finding suggests that future air quality assessments must pay greater attention not only to the quantity of airborne particles but also to their source.

Smoke can travel thousands of kilometers
The impact of forest fires on air quality is not limited to the area where the fire originates.
Wildfire smoke can be transported thousands of kilometers by atmospheric currents, crossing borders and even oceans. Consequently, the WMO views the monitoring of wildfire smoke as an increasingly important scientific and public health issue.
Data from 2025 highlighted the impact of major fires on air quality in regions such as northern Canada, parts of Russia, and northwestern Spain.
This situation demonstrates that air pollution cannot be managed solely through local emission policies; a city may reduce its own traffic and industrial emissions yet still be affected by smoke from a fire hundreds or even thousands of kilometers away.
Ozone risk increases as temperatures rise
Another pollutant highlighted by the WMO is ground-level ozone. The ozone layer in the upper atmosphere protects Earth from harmful ultraviolet rays. However, ozone formed near the ground is an air pollutant that harms human health and plants.
High temperatures, intense sunlight, and stagnant atmospheric conditions can accelerate ozone formation. Consequently, heatwaves do not merely pose a direct risk due to heat; they can also degrade air quality.
The WMO points out that increased ozone exposure could be linked to tens of thousands of additional premature deaths in the future.

Why should air pollution and climate be addressed together?
The new report’s core message extends beyond individual pollutants.
Air quality and climate change are parts of the same atmospheric system.
Reducing fossil fuel use can lower both greenhouse gas emissions and many air pollutants. Conversely, hotter and drier conditions increase wildfire risk, potentially exacerbating air pollution caused by wildfire smoke.
Therefore, simply reducing traffic or industrial emissions may not be enough. The WMO emphasizes that climate and air quality policies should be designed to complement each other.

A new equation for clean air
The new WMO report reveals a changing landscape in the fight against air pollution.
On one hand, there are long-standing efforts to reduce emissions from vehicles, industry, and energy production. On the other, there are heatwaves and wildfires—along with the smoke they generate—that are intensifying due to climate change.
This does not mean that air quality gains achieved in the past are without value. On the contrary, it makes the fight against climate change an integral part of air quality policies in order to safeguard these gains.
The picture presented by the WMO highlights a simple connection: atmosphere and climate and does not separate air quality from climate. Policies should not separate them either.

Source: World Meteorological Organization, Air Quality and Climate Bulletin No. 6, September 7, 2026.
WMO Air Quality and Climate Bulletin No. 6