Heatwaves and Wildfires Worsen Air Pollution

Heatwaves and wildfires are making the fight for clean air harder, including in Europe, the World Meteorological Organization said in its annual report on climate and air quality.

Higher temperatures help fuel extreme fires, whose toxic smoke contains especially harmful fine particles. They also promote the formation of ground-level ozone, an irritant gas that damages the respiratory system, agriculture and ecosystems.

The WMO released the report on Sept. 7, the International Day of Clean Air. It said stricter rules had reduced emissions from industry and transport in Europe and North America in recent years. At the same time, exposure to PM2.5, the fine particulate matter generated by fires, has increased.

The organization cited a study that found the number of extreme fire events worldwide had tripled since the 1990s. Estimates attributed nearly 100,000 additional deaths to those events between 2010 and 2018. The tiny particles can penetrate deep into the lungs and enter the bloodstream, increasing the risk of heart attacks, irregular heart rhythms, strokes and pulmonary embolisms.

Ozone adds another threat. During heatwaves, high temperatures, stable weather conditions and intense sunlight can drive up ozone levels near the ground. Long-term exposure has been linked to higher mortality, particularly from respiratory diseases. The WMO said increased ozone pollution could also contribute to tens of thousands of additional premature deaths.