UN Warns Wildfires and Heatwaves Threaten Global Air Quality and Health

The World Meteorological Organization (WMO) stated on Monday that increasing wildfires and heatwaves are risking the progress of international efforts to improve air quality and protect human health. The United Nations agency highlighted that while industrial and transport emissions of PM2.5 particles have decreased in Europe and North America, exposure to particles from fires has increased. PM2.5 consists of microscopic particles less than 2.5 micrometres in diameter that can penetrate deep into the lungs and bloodstream.

According to the WMO, extreme fire smoke events have tripled globally since the 1990s. One study cited in the report suggests these events contributed to nearly 100,000 additional deaths per year between 2010 and 2018, though this figure may be an underestimate. The WMO noted that conventional risk models might underestimate wildfire attributable mortality by up to 93 percent because particles from burning vegetation are more toxic than those from other sources.

Heatwaves also contribute to the problem by increasing ground level ozone, which can lead to tens of thousands of premature deaths from respiratory diseases. Additionally, the WMO raised concerns about aerosols, such as black carbon and microplastics. Black carbon deposited on snow and ice reduces sunlight reflection and hastens melting. Microplastics are found in the air, soil, and oceans, with one simulation estimating 51 million tonnes on land and 22 million tonnes in the ocean.

The WMO urged countries to adopt coordinated policies on air quality and climate change, as the two cannot be dealt with in isolation. The agency called for better monitoring of pollutants that are currently under surveyed, including aerosols and ground level ozone.