EU scientists warn of spike in ozone pollution caused by heat wave

Large parts of Europe could experience “very high levels” of surface ozone pollution this week amid a fierce heat wave, the EU’s Copernicus Atmosphere Monitoring Service (CAMS) warned Tuesday.

As temperatures soar, the scientists warned that high levels of ozone pollution seen in southern Europe as a result of the heat will also affect northern and western Europe in the coming days.

Ozone pollution, one of the main components of urban smog, is a so-called secondary pollutant formed when nitrogen oxides — caused by road transport — and volatile organic compounds react to heat and sunlight.

Daily maximum ozone levels reached “unhealthy levels” in Portugal, Spain and Italy last week, as some locations measured in excess of 200 micrograms per cubic meter (μg/m3).

Levels in northern and western Europe surpassed 120μg/m3 Monday and are expected to hit a peak between July 18 and 20.

The EU’s limit value for ozone is 120 μg/m3 over eight hours.

“The potential impacts of very high ozone pollution on human health can be considerable both in terms of respiratory and cardio-vascular illness. Higher values can lead to symptoms such as sore throat, coughing, headache and an increased risk of asthma attacks,” said Mark Parrington, a senior scientist at CAMS.

In 2019, 16,800 premature deaths in the EU were attributed to acute ozone exposure.