For the fourth year in a row, the European daily limit value for particulate matter (PM10) is respected in Flanders and Brussels. The European daily limit for particulate matter is 50 μg / m³ (daily average concentration). This limit may not be exceeded more than 35 days.
In Wallonia the day limit is presumably respected for the third year in a row. This is certainly not yet the case because 33 exceedances of the daily limit were already measured at the measuring station in Marchienne-Au-Pont (Charleroi) at this time (26 December).
The European annual limit values for PM10 (40 μg / m³) and PM2.5 (25 μg / m³) are respected at all measurement points. PM10 is fine dust with a diameter of less than 10 micrometres. PM2.5 is the even smaller fraction with a diameter of 2.5 micrometres
The number of exceedances of the particulate day limit in 2017 is comparable with the number in 2015 and 2016. The annual average PM2.5 and PM10 concentrations also remain at the same level in the last 3 years.
Over a longer period (since 2000), both the annual average concentrations and the number of daily exceedances have decreased significantly. There has been a stagnation in the last 3 years.
The European limit values for particulate matter have therefore been respected for a number of years, and the stricter health advisory values of the World Health Organization (WHO) are exceeded in most places in Belgium.
Table with exceedances of particulate matter: http://www.irceline.be/nl/airquality/measures/fine dust / exceedings
Nitrogen dioxide (NO 2 )
In the traffic stations in “street canyons” (streets surrounded by high buildings) in the big cities and along busy roads, the European NO 2 year limit value of 40 μg / m³ is exceeded. 40 μg / m³ is also the recommended value of the WHO. The NO 2 concentrations hardly decrease (or rise) in urban, high-traffic areas. The increasing volume of traffic and driven car kilometers, the large proportion of diesel cars and the higher than legally permitted emissions of nitrogen oxides in realistic driving conditions (diesel gates) are the main causes of the excessively high NO 2 concentrations.
Table of exceedances NO 2 : http://www.irceline.be/nl/airquality/measures/stikstofdioxide/overcrossing
Ozone (O 3 )
There were 5 ozone days in 2017. An ozone day is a day with at least one measurement site in Belgium exceeding the European ozone information threshold of 180 μg / m³. The alarm threshold of 240 μg / m³ was not exceeded in 2017. The ozone days in 2017 occurred in May (1 day) and in June (4 days). In July and August there were no ozone days, which is quite exceptional. Also in 2016 there were 5 ozone days in Belgium.
Over a longer period the number of ozone days decreases with similar meteorological conditions.
Table of exceedances ozone: http://www.irceline.be/nl/airquality/measures/ozon/overruns
A comprehensive discussion on air quality in 2017 will be available in the course of 2018. The three regions will then also publish annual reports with more information.
More information about the trends of air pollution in Belgium, see air quality annual report in Belgium 2016: http://www.irceline.be/nl/documentatie/publicaties/jaarrapporten/jaarrapport-luchtkwaliteit-in-belgie-2016/view
The latest VMM annual air report in Flanders: https://www.vmm.be/publicaties/luchtkwaliteit-in-het-vlaamse-gewest-2016