Air pollution: wildfires and heatwaves deal double blow to our lungs

A firefighter works on hotspots as a helicopter prepares to drop water on a wildfire in Castaic, California, on 31 August, 2022. (Credit: Keystone/AP Photo/Ringo H.W. Chiu)

Air pollution is set to worsen as climate change leads to more intense wildfires and heatwaves.

Scorching heatwaves and intense wildfires fuelled by climate change are harming the quality of the air we breathe, the World Meteorological Organization (WMO) warned on Wednesday.

​​“As the globe warms, wildfires and associated air pollution are expected to increase, even under a low emissions scenario,” WMO secretary general Petteri Taalas said in a statement, launching the organisation’s annual report on air quality to mark International Day of Clean Air For Blue Skies.

Regions that are already heavily polluted will bear the biggest burden in the years to come, according to the findings, with the majority of the worst affected areas in Asia.

Wildfires could almost double by 2100. As climate change accelerates, droughts and extreme heat are becoming the new normal, increasing the risk of fires in natural areas. The Intergovernmental Panel on Climate Change (IPCC) predicts that if the world keeps emitting high amounts of greenhouse gases, the risk of megafire events like the wildfires in Australia in 2019 or the United States over the past two years will go up by 40 to 60 per cent.

Read more: Climate change is driving wildfires – can we tame the flames?

Fire smoke releases particulate matter (PM), also known as aerosols, that if inhaled over long periods of time can severely affect the lungs, the heart and other organs. These fine particles can also cause the atmosphere to cool down or warm up by either absorbing or reflecting sunlight, according to the WMO’s bulletin. When they settle on the Earth’s surface they also affect ecosystems, polluting the waters and soils.

Last year, fierce wildfires burned through thousands of hectares across the globe, causing some of the highest levels of PM ever recorded in Siberia, Canada and western United States, according to figures from the European weather monitoring organisation Copernicus and cited by the WMO. This year, huge blazes engulfed the Mediterranean basin, causing wildfire emissions in Europe to soar to their highest levels in 15 years.

The heatwave-pollution link. During heatwaves low wind speeds and stable weather conditions allow pollutants to concentrate on the surface and intense sunlight encourages the production of ozone at ground level, according to the report.

While ozone that occurs in the Earth’s upper atmosphere shields us from the sun’s ultraviolet rays, ozone at ground level is a pollutant harmful to human health and the environment.

“We have seen this in the heatwaves in Europe and China this year when stable high atmospheric conditions, sunlight and low wind speeds were conducive to high pollution levels,” said Prof. Taalas. “This is a foretaste of the future.”

Dubbed the “climate penalty”, this extreme production of ozone near the Earth’s surface will mostly affect Asian countries, where a quarter of the world’s population lives.

And while climate change will be a key driver, it is mostly continuing to burn fossil fuels at high levels that will contribute to an increase in ozone levels by up to 20 per cent across Pakistan, northern India and Bangladesh, and 10 per cent across eastern China over the second half of the century.

Marking the international day, UN secretary general Antonio Guterres recalled that last year countries recognised the human right to a healthy environment. “Clean air is now a human right,” Guterres said, noting that “today, air pollution is denying billions of people of their rights”. The UN chief urged states to move away from fossil fuels and invest in renewable energies.