WMO warns wildfires and heatwaves threaten global air-quality gains

Wildfires and heatwaves are putting global air-quality gains at risk by producing microscopic pollutants that can remain suspended in the atmosphere, the World Meteorological Organization said Monday.

The United Nations weather and climate agency emphasized the close relationship between air pollution and climate change. Scientists say climate change is contributing to more frequent and intense heatwaves and wildfires. The WMO said extreme fires are increasing, bringing major health consequences because of the toxicity of their smoke.

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Extreme wildfires are increasing, leading to big health consequences because of the high toxicity of smoke.

Regulations in Europe and North America have helped reduce industrial and transport emissions of fine particulate matter, known as PM2.5. But exposure to PM2.5 from wildfires has risen, offsetting part of that progress. The particles measure less than 2.5 micrometers across, allowing them to penetrate deep into the lungs and enter the bloodstream.

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Air quality and climate change can’t be dealt with separately. If one worsens, the other does too.

PM2.5 comes from industrial activity powered by fossil fuels, farming, domestic heating and transportation, as well as wildfires and dust storms. Lorenzo Labrador of the WMO’s Global Atmosphere Watch network told AFP that air quality and climate change cannot be handled separately. Smoke particles produced by burning vegetation, he said, can be much more toxic than particles from sources such as car exhaust and can harm people and wildlife far from the fire.

The WMO said conventional risk models based on total PM2.5 levels may underestimate deaths attributable to wildfires by up to 93%. One study cited in its bulletin found that extreme fire-smoke events have tripled globally since the 1990s and contributed to nearly 100,000 additional deaths annually between 2010 and 2018, although the figure may be an underestimate. The agency also called for better monitoring of aerosols, including black carbon and microplastics, fine particles and ground-level ozone, which accumulates when temperatures rise, air stagnates and sunlight acts on pollutants.

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In places where there are relatively powerful forest fires, we find a lot of fine particle pollution.