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Trends

The concentrations of the majority of air pollutants have systematically decreased over the past decades in Flanders.

Concentrations of most air pollutants are declining

To derive the trend over the past decades, we calculated the percentage drop of the annual averages with respect to the starting year of the measurements. For benzene and benzo(a)pyrene, the average of all Flemish measuring stations was used. For NO, NO2, SO2, PM and black carbon, we used the virtual urban average, and for CO, the average of the Ghent urban measuring station. For ozone, we used the Flemish modelled average. For lead, finally, we used the values of a measuring station in a hotspot area. These figures show that the air quality in Flanders has systematically improved over the past decades.

Ozone peaks are decreasing, background concentration is increasing

The trend for most gaseous pollutants is favourable. It is striking that ozone pollution, characterised by ozone peaks, has markedly decreased in recent years (light green line in Figure 1). Local and European measures to reduce ozone precursors are therefore successful. However, increasing emissions in the northern hemisphere with, amongst other things, the expansion of Chinese industry result in increasing ozone background concentrations (dark green line in figure below). Measures are therefore required on a global scale.

 trend of gaseous pollutants  Figure: trend of gaseous pollutants

 

Decrease in particulate pollutants

Particulate pollutants have also dropped since the year in which the measurements started. The drop is most pronounced for PM2.5 and black carbon. The curve of the PM10 concentration and benzo(a)pyrene is slightly more erratic, but here too we see a steady decline in recent years, see figure below.

 Trend of particulate pollutantsFigure: trend of particulate pollutants

 

A slightly upward trend for lead near non-ferrous plant in Hoboken

Intensive clean-up operations resulted in a marked decline in lead concentrations in the vicinity of a non-ferrous plant. In 2016, the lead content in the ambient air was only 8 % compared with the level in 1978, see Figure 3. In recent years, however, the trend has again reversed; the European limit value for lead was exceeded at one measuring station in 2015 and equalled in 2016.

Figure trend of lead concentration near a non-ferrous plant in Hoboken

Figure: Trend of lead concentration near a non-ferrous plant in Hoboken

Read the extended summary air quality 2016

 

VMM contributes to a better air quality in Flanders. We continuously monitor the air quality by measuring the presence of harmful substances in the ambient air.

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