On Saturday 21 June 2025, the air quality in the south and center of the Netherlands will be ‘poor’ due to smog due to ozone. This may cause discomfort for people who are sensitive to smog. RIVM advises them to stay indoors and limit strenuous physical activity. This advice is most relevant in the late afternoon and early evening, when the air will be most polluted.
Smog from ozone may cause a worsening of respiratory symptoms, such as coughing and shortness of breath, as well as a worsening of asthma symptoms and reduced lung function. It may also irritate the eyes, nose and throat. Relatively speaking, people with respiratory symptoms, children and the elderly are most sensitive to smog. Contact your GP or Municipal Public Health Service (GGD) if you experience symptoms.
Ozone forecast for the days ahead
On Saturday, the amount of ozone in the air will rise and this will locally lead to smog in the center and south of the Netherlands. In the north, the ozone concentrations are lower. On Sunday, the ozone will rise again, but no smog is expected. From Sunday afternoon, cooler and cleaner air will come from the west, which will have a positive effect on the amount of ozone.
Smog due to ozone
Smog due to ozone is the result of an accumulation of pollutants in the air on sunny days. This occurs in spring and summer when there is little wind (that is mainly blowing from the south-east). The pollutants include nitrogen oxides and volatile organic compounds, which the sunlight turns into ozone. This is also known as ‘summer smog’. In other seasons, the UV radiation is not high enough to create significant amounts of ozone concentrations.
EU (European Union ) information and alert thresholds for ozone
The EU has established information and alert thresholds for ozone. The EU information threshold is 180 micrograms per cubic metre of air. When this threshold is crossed (or about to be crossed), people who are sensitive to smog may start experiencing symptoms. RIVM will send out a warning when this happens. As per the Dutch air quality index, the air quality will be ‘poor’.
The EU alert threshold is 240 micrograms per cubic metre of air (air quality of ‘very poor’ according to the Dutch air quality index). When this threshold is crossed, everyone may start experiencing symptoms. RIVM will change the warning to an alert before this happens.
More information
- Visit luchtmeetnet.nl or NOS Teletext page 711 for current and expected smog levels.
- Visit rivm.nl for the maximum concentrations per hour or eight-hour period, as measured by the monitoring stations in the National Air Quality Monitoring Network over the last few days.
- You can also visit rivm.nl for more information about smog.
- Read more about lung diseases and air pollution on the website of Lung Foundation Netherlands (Longfonds).