Extreme heat makes air quality worse\u2013that's bad for health

Commuters make their way down a smoggy road in Lahore, Pakistan in 2022. Extreme heat waves make air pollution, like smog, worse. Arif Ali/AFP via Getty Images hide caption

toggle caption Arif Ali/AFP via Getty Images

Commuters make their way down a smoggy road in Lahore, Pakistan in 2022. Extreme heat waves make air pollution, like smog, worse.

Arif Ali/AFP via Getty Images

This summer, daytime temperatures topped 100 degrees for a full month in Phoenix. In northwest China, temperatures soared above 125 degrees. Southern Europe withstood waves of 100-plus degree days. Wrapped together, heat waves illustrate a sobering reality: . But isn't the only outcome of : air pollution spikes when the temperatures rise according to a .

"Climate change and air quality cannot be treated separately. They go hand in hand and must be tackled together to break this vicious cycle," WMO Secretary General Petteri Taalas said in a press release.

, which can pump enormous plumes of smoke into the air. That but also for people thousands of miles downwind.

Emergency room visits for asthma spike. Heart attacks, strokes, and cognitive function problems also increase after smoke exposure. In 2022, people living in the Amazon basin, Alaska, and the western part of North America all breathed in more wildfire smoke than they have on average over the past 20 years.

Extreme heat also drives up the , which in turn makes big dust storms more likely. Enormous clouds of fine dust wafted off major deserts last year, particularly affecting the Arabian Peninsula region. Southern Europe also got hit by a major dust storm after a heat wave baked the deserts of northern Africa in the summer.

Hot air temperatures also encourage the — a clear, odorless gas that irritates people's lungs. It's the main component of smog. Ozone forms when pollutants, , react with heat and sunlight. It forms both high in the atmosphere, where it helps protect the planet from ultraviolet radiation from the sun, and near the ground, where humans live and breathe.

sent ozone concentrations across southern Europe well into unhealthy levels for weeks, the report says.

"That's a very bad combination of conditions," says Julie Nicely, an atmospheric chemist at the University of Maryland, College Park, who worked on the report. That mix is particularly dangerous for elderly people, or people with breathing sensitivities. "That is very bad for the lungs and the cardiovascular system. It's just very unhealthy," she says.

Air pollution levels have dropped across the Northern Hemisphere in the past few decades in response to environmental regulations like the Clean Air Act in the United States. Ozone pollution, however, remains a problem. The report authors point out that the extra heat in the atmosphere driven by climate change overpowers even the gains made by stringent environmental protections. The authors said that underscores the importance of slowing or reversing human-caused climate change as quickly as possible.