Tourists hold umbrellas to protect themselves from the sun during a heatwave at the Trocadero square, in Paris, on June 30, 2025. French authorities put Paris on red alert for extreme heat and Spain and Portugal reported record temperatures as a heatwave gripped southern Europe and Britain on June 30, 2025, triggering health warnings and fuelling wildfires. (Photo by Ludovic MARIN / AFP) (Photo by LUDOVIC MARIN/AFP via Getty Images)

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With temperatures set to soar again in Europe, the link between heatwaves and air pollution is back under the spotlight.

This is because hot sunny conditions also aid the formation of super pollutants, like tropospheric zone, black carbon and methane, which pollute the air, causing impacting human health and damage to crops.

And all the signs are as the heatwave season grows longer and more intense, we will also see more air pollution as well.

For example, May was the second warmest on record globally across land and sea, according to the Copernicus Climate Change Service (C3S).

According to the C3S data, the month was marked by a rapid transition from much cooler-than-average conditions to one of the most intense heatwaves ever observed this early in the year in western Europe.

Last month saw large parts of western, central and eastern Europe experience drier-than-average conditions.

And figures from the Met Office in the U.K, reveal England and Wales had the warmest spring on record, and the late-May heatwave saw six consecutive days above 30 degrees Celsius in some areas.

Figures also show France saw an unusually early nationwide spike in ozone pollution in May, and the dry and sunny weather along with light winds also resulted in increased levels of air pollution in some U.K locations as well.

Laurence Rouil, director of the Copernicus Atmosphere Monitoring Service (CAMS), said high concentrations of ozone are typically seen towards the end of June and throughout July and August, but the “ozone season” appears to be starting earlier.

She said ozone results from chemical reactions of several pollutants, including nitrogen oxides, which are emitted by vehicles and industries and volatile organic compounds, which can be generated through chemical manufacturing, solvents use, but can also be released by vegetation.

The chemicals react with sunlight and high temperature to produce ozone.

She added wildfires are also increasing of ozone concentrations everywhere in Europe and the U.S since they emit chemical precursors.

“It's very important to find solutions to mitigate ozone, because it is related to respiratory disease and cardiovascular issues and had harmful impacts on ecosystems and crop yields” she told me.

“The health community is also concerned that a combination of exposure to ozone concentration during summer months and high temperatures is a big issue for human health.”

Rouil said if high ozone events are predicted, they could be mitigated locally by reducing industrial emissions of volatile organic compounds or by limiting vehicles on the road.

Rachel Huxley, the head of mitigation in the climate and health team at the charitable foundation Wellcome, said climate change is increasing the intensity, frequency, and duration of heatwaves, in an interview.

Huxley added heatwaves are usually caused by high air pressure systems, leading to less air movement and increasing the build-up of air pollution, with methane and other pollutants reacting to create ground-level ozone – a component of smog.

She said ground-level ozone can also damage agricultural crops, for example ground-level ozone ‘burns’ plant cells and affects the ability of forests to store carbon.

But Huxley added the transition to clean energy, the greater use of active transport measures, and the electrification of industry could all help reduce air pollution and greenhouse gas emissions.

“Some aspects of air pollution can be very local, but some are more regional, and we cannot solve ground-level ozone or the air pollution issue without regional and global efforts,” she told me.

“Tackling super pollutants is one of the best ways we can reduce warming in the near term and could have a major impact in terms of extreme heat in the coming decades.”

And Albert Presto, the director of the Center for Atmospheric Particle Studies at Carnegie Mellon University said evaporation emissions from gas station visits and petrol-powered lawnmowers can also increase air pollution during heatwaves.

Presto added wildfires can also exacerbate both ozone and particle (PM2.5) air pollution over the summer months.

“Every city can be impacted differently because of the differences in the way it is laid out, what it’s topography is like and other meteorological factors, but in general cities get more polluted when they are hotter,” he told me.

“And because ozone is dependent on temperature, warmer springs and warmer falls will lead to an extension of the ozone season.”