Climate change exacerbates ozone pollution: Swiss research

Ozone pollution continues to rise due to climate change Keystone-SDA

The increasing frequency of heatwaves is impacting ozone concentrations in the lowest layer of the atmosphere, according to Swiss research.

Sunny and dry weather promotes the formation of ground-level ozone, as the Swiss Academy of Sciences (SCNAT) noted in a fact sheet. Despite improved air quality, the ozone limit value at ground level is regularly exceeded.

+ Ozone continues to cause summertime blues

Whilst the ozone layer in the stratosphere protects against harmful UV radiation, the gas at ground level irritates the respiratory tract, damages plants and acts as a greenhouse gas.

Although Switzerland has significantly reduced emissions of ozone precursors through stricter regulations, the limit values are still regularly exceeded. This can be partly attributed to natural processes and the complex photochemical formation of ozone. However, climate change is exacerbating the phenomenon.

Furthermore, the protective ozone layer is recovering only slowly, despite the ban on chlorofluorocarbons since 1989. Emissions of the ozone-depleting substance nitrous oxide are even on the rise due to the increasing global use of fertilisers.

According to SCNAT, global monitoring is crucial for tracking these developments. Switzerland contributes to this with the world’s longest series of ozone measurements, which began 100 years ago in Arosa and is now continued by the Federal Office of Meteorology and Climatology, MeteoSwiss, in Davos.

The first measurements can be traced back to the physicist FW Paul Götz, who originally studied solar radiation at a tuberculosis sanatorium in Davos. He wanted to scientifically document the effects of the Alpine climate on health, as detailed in a blog post by Meteoschweiz.

In collaboration with the British physicist Gordon Dobson, Götz began using a so-called Dobson spectrophotometer on July 23, 1926. It measures how the atmosphere filters sunlight depending on its wavelength. This instrument became the global standard for measuring total ozone and is still in use today.

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Translated from German, reviewed by an English Department journalist.