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Peak ozone level

Sun in the sky and some clouds
Ozone is a gas found in our atmosphere. We need ozone to protect us from the sun's UVC radiation. An excessively high ozone concentration can have consequences for our health, for example difficulties in breathing. During the months of May, June, July and August, there may be ozone peaks in our country.


Your behaviour

  • Opt for greener mobility: public transport, cycling, walking, carpooling.
    • Do not use your car for short distances.
    • Try to consume less fuel by driving in a less sporty way.
    • Maintain your car well.
  • Insulate your home properly.

Your health

  • Ask your doctor if an ozone peak can have a particular impact on your health.
  • Consult the website http://www.irceline.be/ for the current air quality situation.


Your behaviour

  • Do not run your engine when stationary.
  • Do not refuel during the hottest time of the day.
  • Stay indoors, where the ozone concentration is lowest.

Your health

  • Inform yourself and follow the recommendations of the government.
  • Limit your outdoor activities between 12 p.m. and 10 p.m. This applies in particular to:
    • Elderly people
    • People with heart or lung problems
    • Babies and children
  • Consult your doctor if you experience unusual breathing problems.
  • Visit people in your surroundings who you know may be experiencing problems due to an ozone peak.


  • There are no specific recommendations.

Impact and probability


Large-scale deterioration of air quality. Impact: low impact. Probability: very likely.Extreme weather events occur several times each year and are expected to become even more extreme and more frequent in the future due to the influence of climate change.

In 2018, the National Crisis Center coordinated a large-scale risk assessment for Belgium for the period 2018-2023. Several experts assessed various risks based on their probability and their impact on people, society, the environment and the economy.

For the risk of 'large-scale deterioration of air quality', the analysis is:

  • Impact: low impact
  • Probability: very likely

Read more about this analysis and what this chart means here. 

What do the authorities do?

The various authorities in Belgium have an ozone and heat plan. This plan consists of 3 phases:

  • Vigilance phase: every year from 15 May to 30 September.
  • Warning phase: when the temperature threshold is exceeded.
  • Alert phase: when:
    • The temperature threshold of the warning phase has been reached.
    • The predicted maximum temperature for the day is higher than or equal to 28 °C.
    • A too high ozone concentration has been measured at at least one measurement point.
    • The measures already taken need to be reinforced.

Each regional government adopts measures during a vigilance or warning phase, for example supporting professionals who work with vulnerable groups. When a state of alert is declared, the federal government assumes a coordinating role.