Czech scientists report growing levels of ground-level ozone

Illustrative photo: Barbora Němcová

Czech scientists have discovered growing concentrations of ground-level ozone around the Czech Republic. The phenomenon, typical mainly for the summer months, now occurs even during winter. It is caused mainly by global climate change, but surprisingly, also by better air quality.

Ground-level ozone is not directly emitted into the atmosphere. Instead, it forms in the air through reactions between other pollutants from cars, power plants and industrial sources.

Scientist Iva Hůnová, who works at the Czech Hydro-Meteorological Institute and the Faculty of Life Sciences, says breathing ozone can lead to serious health problems:

“Molecules of ozone are very reactive. If they enter our organism, they react with other substances and create free radicals. They can seriously harm cells, deteriorate breathing, cause all kinds of illnesses and contribute to a rise in the mortality rate.”

Compared to the situation in the country 20 or 30 years ago, the maximum concentrations of ground-level ozone are significantly lower than they used to be. What is disconcerting, however, is that the average measured concentrations have been gradually increasing since 2014.

Photo: Jana Šustová

The situation is most serious in the immediate vicinity of big cities, within a distance of twenty to thirty kilometres. That’s where the wind transports particles of harmful substances that contribute to the creation of ground-level ozone.

However, scientists have recorded relatively large concentrations of ground-level ozone in places where they wouldn’t expect it, says Iva Hůnová, who has been monitoring its concentrations on a long-term basis:

“Ozone concentration is high even in relatively unpolluted areas, such as in the mountains. There are high concentrations both during the night and during the day, unlike in the cities, where the levels drop at night.”

Higher levels of ground-level ozone have been regularly registered for example in the Krušné Hory mountains, in the north-west of the Czech Republic.

The same results were confirmed by scientists from the Freiberg Technical and Mining University in Saxony, who measured ozone concentrations on the German side of the mountains.

Surprisingly, one of the reasons behind the growing occurrence of ground-level ozone in places with clean air is better filtering of pollutants in industrial areas.

While most of the harmful substances released into the air contribute to the increase of ozone levels, some of them, including nitric oxide, actually help to eliminate it.

Ozone concentrations are also increasing due to global climate change. Slowing down its effects is therefore one of the major steps to cut them down, along with lowering emissions of harmful substances.

High concentrations of ground-level ozone are also harmful to the country’s already weakened forests, which have been afflicted by bouts of dry weather and bark-beetle infestation.

According to a recent study carried out by the United Nations, Czech Republic’s forests are the most affected in the Central European region and have already lost their ability to absorb carbon dioxide.