On Thursday, June 27, the air quality in Overijssel, Drenthe, and Groningen is expected to be "poor" due to ozone smog. People who are sensitive to smog may be affected. RIVM advises them to stay indoors and limit strenuous physical activity. This advice is especially relevant in the late afternoon and early evening when the air is most polluted.

Smog caused by high ozone concentrations can lead to an increase in respiratory symptoms, such as coughing and shortness of breath, aggravation of asthma symptoms and a decrease in lung function. Other symptoms include irritation of the eyes, nose and throat. People suffering from respiratory conditions, children and the elderly are relatively often sensitive to smog. If you are experiencing symptoms, please contact your GP (general practitioner) or the Municipal Public Health Services (GGD).

Ozone forecast for the next few days

Due to the wind shifting to the southwest, ozone concentrations are expected to be lower starting tomorrow. The air quality is anticipated to be "poor."

Smog from ozone concentrations

Smog from ozone is formed as a result of the accumulation of air pollution on sunny days, which is a phenomenon that occurs in spring and summer when there is little (usually south-easterly) wind. The pollutants, such as nitrogen oxides and volatile organic compounds, are converted into ozone under the influence of sunlight: this is also known as summer smog. Throughout the other seasons, the sun is not strong enough to cause the formation of high ozone concentrations.

European information and alert threshold for ozone concentrations

In Europe, an information and alert threshold has been established for ozone concentrations. The  EU European Union (European Union)(Europese Unie) Information threshold is defined as 180 micrograms of ozone per cubic metre of air. Any (imminent) exceedance of this value may lead to people, who are sensitive to smog, developing symptoms. In such cases, RIVM will issue a warning. The Netherlands Air Quality Index rates air quality as ‘Poor’ in such instances.
The EU Alert threshold is defined at 240 micrograms of ozone per cubic metre of air (ranked ‘Unhealthy’ according to the Netherlands Air Quality Index). Anyone is at risk of developing symptoms once this value is exceeded. If the values threaten to go above the threshold, RIVM will convert the warning into an alert.

Additional information in Dutch