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What measures against smog episodes are taken in Belgium?


The European Commission obliges member states to create action plans in order to limit the risk of exceedances of the target and limit values and the duration of said exceedances. These plans might consist of controle measures and, if necessary, prohibition of certain activities that contribute to the exceedance of the limit values (road traffic included). Member states can take into consideration more specific measures to protect the most vulnerable population groups, for example children.

On 2 September 2008 the ministers of Environment of the three regions, together with the Interregional Cell for the Environment (IRCEL) have adopted the protocol that determines the coordination during pollution episodes. The protocol is activated in occurence of pollution peaks of PM10 or NO2. Based on the partnership agreement between the Brussels, Flemish and Walloon Regions regarding the supervision of airborne emissions and of the restructuring of the data (Belgisch Staatsblad 24-06-1994, p 17211), the task of IRCEL is "to monitor phases of increasing pollution and to warn the agencies responsible appointed by the Regions". More specifically, IRCEL distributes an information bulletin in case increased concentrations of PM10 and/or NO2 are forecasted of measured. These tasks are being executed since December 2003 on demand of the Brussels Capital Region, since January 2005 on demand of the Flemish Region and since December 2005 as requested by the Walloon Region.

To predict episodes of increased concentrations, IRCEL uses forecasts derived from meteorological models (ALADIN, ECMWF) to identify dispersion conditions. In addition, forecast originating from models run at IRCEL itself are used to predict concentrations (a.o. SMOGSTOP, OVL and CHIMERE). These different information sources are analysed, compared and confronted with earlier experiences within the field of air quality forecasts.

Activation of the protocol

The activation of the protocol happens in two phases: a pre-alarm phase, followed by an alarm phase.

   1. Pre-alarm phase

This phase will be initiated to prepare certain services of the Regions in a state of readiness and starts if forecasts point towards exceedances of the regional threshold values of 70 µg/m³ (daily mean) for at least two subsequent days for PM10. For NO2, one of the most important pollutants within the traffic sector and is specifically part of the Brussels' plan of action, a first threshold is set at 150 µg/m³.

The threshold of 70 µg/m³ is used in all three Regions, only the geographical interpretation differs:

Brussels: the daily mean concentration of 70 µg/m³ has to be reached in at least two measuring stations in Brussels

Wallonia: the concentration of 70 µg/m³ has to be reached on average in two geographical zones in Wallonia, in the north and the south.

Flanders: the daily mean concentration of 70 µg/m³ has to be reached across the whole Flemish Region

   2. Alarm phase

The alarm phase is activated one day before an episode with increased pollution. This phase only takes place if the forecasts at IRCEL confirm the risk of increased pollution that was previously predicted during the pre-alarm phase.

The activation of the alarm phase implies IRCEL spreading an inforation bulletin containing following data:

The causes of the episode of increased pollution

The current situation and the expected evolution

The nature of the pollutants

General recommendations for public health and actions to be taken to limit the emissions.

Elongation and end of a smog episode

A smog episode predicted by IRCEL always lasts at least two days. In case of a smog episode lasting longer than two days, IRCEL communicates an internal message on the suspected evolution of the situation, starting on the second day. If necessary, a message can be sent to the press. Based on analyses and interpretations of measured and predicted values, IRCEL communicates about the end date of the smog episode and does so one day before this end. This message is also integrally communicated to the media.

Activation of regional action plans

When the alarm phase is in effect, each Region has to activate the measures as foreseen by the emergency plans for peak concentrations of particulate matter.

For more information on the regional plans, we refer to the sites below:

Brussels Capital Region:

Walloon Region:

Flemish Region:

In addition to the threshold value of 70 µg/m³, the plans in Brussels and Wallonia provide two additional intervention thresholds (100 and 200 µg/m³) with additional measures. For NO2, two additional threshold values are set at 200 and 400 µg/m³.