Two-thirds of EU faced harmful ozone levels during heatwave: report
PARIS: Two thirds of the European Union’s population may have been exposed to harmful levels of ozone pollution during last month’s record-breaking heatwave, a report warned on Thursday.
Nearly 300 million people, including 100 million children and elderly people, faced higher-than-recommended levels of the toxic pollutant during the punishing heat in late June, according to the report from the NGO Global Witness.
The scale of this “invisible threat” highlights how “people are being forced to live through very dangerous conditions as a result of our dependence on fossil fuels,” the organisation’s senior campaigner Flossie Boyd said.
Ground-level ozone is different from the ozone layer in the atmosphere, which protects Earth from the Sun’s radiation — and is slowly recovering from damage made by refrigerants called CFCs.
On the ground, ozone is the main ingredient in smog and can cause breathing problems, damage lung tissue, trigger asthma attacks and lead to other health issues.
More than 63,000 deaths as well as billions of euros in crop damage were attributed to ozone pollution in 2023 alone, according to the European Environment Agency.
At ground level ozone is created by chemical reactions triggered by high temperatures and strong sunlight during heatwaves. The new report was published just hours after the EU’s climate monitor Copernicus announced last month was Western Europe’s hottest June on record.
‘Worrying’
The report combined data from 162 air quality monitoring stations across Europe, atmosphere modelling and census information to estimate continent-wide ozone levels from June 21 to 28. It found that nearly 298 million people across the continent were exposed to levels above the EU’s recommended maximum daily eight-hour average of 120 micrograms of ozone per cubic metre.
Around 87 percent of the EU’s 450 million people were estimated to have faced levels exceeding the World Health Organisation’s lower guideline of 100 micrograms per cubic metre. And 72 million people faced the “most dangerous threshold” of 150 micrograms per cubic metre, the report added.
Two thirds of the monitoring stations gave readings that were in the top percent of all June days dating back to 2013, the report said. The highest was 233.7 micrograms per cubic metre in the German state of North Rhine-Westphalia on June 27. Ground-level ozone is created by chemical reactions that involve nitrogen oxides, commonly from traffic, as well as organic compounds largely from human-driven methane emissions.
If these chemicals are not emitted in the first place, then ground-level ozone does not form, explained Laurence Rouil, director of the Copernicus Atmosphere Monitoring Service (CAMS), whose modelling data was used in the report.
Compared to a particularly deadly heatwave that struck Europe in 2003, this latest episode is “really remarkable and worrying” because it came so early in the summer, Rouil said. “International collaboration is essential to tackle the ozone issue,” she added.
Published in Dawn, July 10th, 2026
