Around half of the global population has been exposed to dangerous levels of ground-level ozone this year, a new report finds.
Though ozone high up in Earth’s stratosphere provides protection from ultraviolet radiation to people and other life on the planet, ground-level ozone is a toxic pollutant. It’s the main ingredient in smog and can cause lung damage and harm vegetation such as crops.
Ozone, which is made up of three oxygen atoms, forms when emissions of other pollutants such as carbon monoxide and nitrogen oxides from fossil-fuel burning or wildfires mix with sunlight and heat. And the world saw a lot of heat this summer.
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Those summer heat waves, amplified by climate change, are part of the reason some 51 percent of people in the world were exposed to “very poor” or “extremely poor” average ozone concentrations in the past six months, according to a report released September 29 by the Copernicus Atmosphere Monitoring Service (CAMS). Both categories exceed the World Health Organization’s guidelines for exposure to the pollutant. Some 34 percent of people were exposed to extremely poor concentrations. A mere 5 percent experienced “good” conditions.
Amanda Montañez; Source: Copernicus Atmosphere Monitoring Service, European Center for Medium-Range Weather Forecasts (data)
Asia saw the highest levels of ground-level ozone, with 75 percent of people exposed to at least very poor concentrations, followed by North America and Europe.
The CAMS report noted that both the ozone and the pollutants that lead to it can move across international borders, which makes reining it in a more difficult task.
“Ozone pollution is a stark reminder of how interconnected our atmosphere, climate, health, and livelihoods really are, with pollution and our changing climate impacting the chemistry of the air we breathe, determining the health of our ecosystems, and even governing our ability to grow food,” CAMS director Laurence Rouil said in a statement.