Wildfire Emissions Surge, Putting Millions at Risk of Worse Air Pollution

BRUSSELS, July 31 - Wildfires in France and Spain have exposed millions of people to harmful air pollution over the past several days, scientists said Thursday.

Smoke from fires contains a mix of pollutants that lower air quality even hundreds of kilometers away. Scientists said they are especially concerned about emissions of fine particulate matter, known as PM2.5, which is linked to heart disease, lung cancer and breathing problems.

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"We know this has a really significant health impact, especially when people are exposed for multiple days," said Theodore Keeping, a climate scientist at Imperial College London.

"We're seeing more severe and frequent high-intensity fires where people are exposed to these very, very high PM2.5 levels."

In the French city of Bordeaux, PM2.5 pollution levels spiked to above 300 micrograms per cubic meter on July 26, data from the EU's Copernicus Atmosphere Monitoring Service showed. Keeping said Bordeaux’s PM2.5 levels averaged 115 micrograms on July 26 — nearly five times the EU’s daily average limit.

Smoke plumes carried unusually high PM2.5 concentrations downwind of Madrid and Bordeaux. In Limoges, a city more than 200 kilometers (125 miles) northeast of Bordeaux, PM2.5 levels peaked above 400 micrograms per cubic meter over the weekend.

"They are producing massive amounts of smoke... we see it spreading across central Spain and southern France," said Mark Parrington, a senior scientist at the European Centre for Medium-Range Weather Forecasts.

Wildfires can make PM2.5 even more hazardous, increasing the particles’ toxicity as they mix with other components in smoke.

"It can also have a lot of other very unpleasant substances attached to the particles which, being smaller, are the ones that can really enter the lungs and worsen respiratory illness," Parrington said.

He urged people in impacted areas to follow local officials’ guidance, such as keeping windows shut, remaining indoors, or wearing masks.