Increased pollution from climate events such as wildfires and heatwaves has put global efforts to improve air quality and protect the planet’s environment at risk, says a recent report from the World Meteorological Organization (WMO).
The report, the sixth edition of the WMO ‘Air Quality and Climate Bulletin,’ examines the complex relationship between air quality and climate. “The WMO report highlights the need for clearer atmospheric observations of air pollutants such as fine particulate matter and ground-level ozone, as well as aerosols like black carbon and micro plastics, which are not sufficiently monitored even though they are widespread and are potentially harmful to ecosystems,” says the WMO in its report, a copy of which is with The Plurals.
“It stresses the importance of complementary and coordinated policies on air quality and climate because they cannot be dealt with in isolation,” it adds.
Fire adds to fine pollutant level
“In keeping with trends in recent years, PM2.5 concentrations in 2025 were above the long-term average in northern Canada, part of the Russian Federation and western-central Africa due to increased fire activity,” the WMO report pointed out. “North-western Spain was also a hot spot because of exceptional fires in late summer 2025.”
PM2.5, ultrafine particulate with 2.5 micrometres or less in diameter, can penetrate deep into the lungs and bloodstream, triggering a range of diseases including the fatal ones. PM2.5 pollutants are generated from industrial work, agriculture, residential heating, transport to wildfires and dust storms.
Severe wildfires have gone up globally, impacting health with the high toxicity of smoke. Europe and North America have reduced industrial and transport PM2.5 due to regulations, but fire-related PM2.5 has increased in these continents.
At least 100,000 additional deaths per year due to fire events
“India continued to have above average levels because of biomass burning and other pollution, according to the bulletin which, for the first time, used models from four different sources,” says the WMO.
South America’s Amazonia showed lower PM2.5 levels as burning was relatively lower in 2025 than in previous years. China, too, showed a decline in emissions from human activities in 2025.
“One study cited by the WMO Bulletin indicates that extreme fire-smoke events have tripled globally since the 1990s, contributing to an estimated nearly 100,000 additional deaths per year between 2010-2018 – although this may well be an underestimate,” says the WMO.
Conventional risk models fails to assess most wild fire triggered deaths
Conventional risk models, says the WMO report; can fail to capture the full toxicity of wildfire-induced mortality. An epidemiological study showed that such models, based on total PM2.5 concentrations, may underestimate wild-fire-attributable mortality by up to 93%.
“Meeting the World Health Organization air quality guidelines will become progressively more difficult, since extreme fire weather is expected to increase in the future,” it says. An increasing problem resulting from heatwaves is ground-level ozone pollution.
“Rising temperatures, stagnant atmospheric conditions and intense solar radiation promote ground-level ozone formation, as shown by recent studies during heatwaves in the south-eastern USA, Europe and China,” the WMO says.
Long-term exposure to ozone pollution is linked to higher mortality, primarily through respiratory diseases. “Looking forward, ozone-related health risks are expected to intensify,” the report says.
Microplastics among the most dangerous pollutants
Aerosol particles can move far away from their sources, across oceans and continents, and can transform how the atmosphere reflects sunlight. They can alter the chemical properties of land and water bodies and pollute clean environments.
For example, deposits of black carbon (soot) on snow and ice reduce the amount of sunlight reflected by these surfaces and speed up the melting process.
Micro plastics, formed when plastics break down due to sunlight and other factors, are among the most damaging pollutants affecting human health. They are ubiquitous, found in the atmosphere, on land and in the ocean. An Earth System Model simulation estimated the amount to be 51 million tonnes for land and 22 million tonnes for the ocean, which in turn becomes a source of microplastics for the atmosphere. There are hugely varying estimates due to lack of data, but this is a vicious cycle.
“As plastic production and, critically, mismanaged plastic waste, continues to increase, monitoring atmospheric pathways of deposition of microplastics to remote environments will be crucial towards understanding their overall impacts on the Earth system,” says the Bulletin.