“Climate impacts and air pollution respect no national borders––as exemplified by intense heat and drought, which fuels wildfires, worsening air quality for millions of people. We need improved international monitoring and collaboration to meet this global challenge,” said Ko Barrett, WMO Deputy Secretary-General, in a news release.
Other sources of pollution include black carbon, nitrous oxide and ground-level ozone, which all contribute to and exasperate climate change, WMO said, calling it a “vicious cycle.”
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Fine particulate matter (PM2.5) refers to particles suspended in the air that are less than 2.5 micrometres (μm) in diameter. The amount of particles found in transport, industry and agriculture, as well as from wildfires and wind-blown desert dust, remains a significant health hazard, WMO says.
Its latest bulletin said above-average levels of PM2.5 were found in Canada as a result of the extreme wildfire season in 2024. Levels were also higher than usual in Siberia and central Africa. Meanwhile, it found pollution hot spots in northern India, but PM2.5 levels were on the decline again in eastern China as a result of its mitigation measures in place.
PM2.5 explainer. (U.S. Environmental Protection Agency (EPA))
Canada also saw an increase in fine particulate matters indoors in early June, with Airthings saying that its data indicated PM2.5 levels soared to unsafe levels in homes across the country.