Report Forum 2040
Thematic session on the impact of Vision 2040 in terms of ground noise, air quality and urban impact
The third session of Forum 2040 was an opportunity for further discussions on the impact of the various options presented by Brussels Airport Company under the Strategic Vision 2040. This third session had focused in particular on impacts on air quality, ground noise and urban impact.
As an introduction, the chairman explained that two participants had sent their comments on the minutes of the session of 25 October. A reference was made to the necessity of examining a third option regarding the development of the airport, one which would involve another organizational model of Brussels Airport Company and which would consider the limitations of the current urban context. Some concerns were raised regarding the method used by To70 to calculate the people strongly impacted by aircraft noise and the Lden criteria. The President replied that he took note of these elements and that they were communicated to the management of Brussels Airport Company.
Next, Piet Demunter, Director for Strategic Development at Brussels Airport Company, explained the initiatives the airport had already taken in recent years to mitigate the impact of its activities in these various fields. This way, the participants gained insight into various measures that are being taken to limit ground noise, limit emissions,...
Four experts shared with members of Forum 2040 the results of their studies in terms of ground noise, air quality and urban planning.
In response to comments by some participants at the previous session, everyone attending received a paper copy of the presentations.
The following experts presented their results:
- Johan Versieren (Tractebel) and Jan Peters (VITO) on air quality and the issue of fine particles
- Christ Glorieux (KU Leuven) on impact in terms of ground noise
- Bart Antheunis (Arcadis) on impact in terms of urban planning
As in previous sessions, the participants were divided into three groups to continue their discussions on the content of the presentations. The various experts, together with Mr Demunter and the chairman, Lode Willems, visited each of these groups in turn and answered participants’ questions.
Suggestions and thoughts on air quality
Overall, we can conclude that opinions differed on the impact on health of ultra-fine particles (UFPs). On the one hand, the risks of UFPs for health were identified by certain participants. On the other hand, VITO experts indicated that there were very few scientific studies on the subject. The impact of road-traffic related UFPs on health was not proven and even less so for air-traffic related UFPs. The suggestion was made to apply the precautionary principle in such cases. The Tractebel experts emphasised that UFP emissions would decrease over the next few years, as a result of the technological evolutions in vehicle engines.
- It was pointed out that in Schiphol, the reference measurements were taken 40 kilometres from the airport. One regretted that measurements at Brussels Airport were taken only 7 km from the airport, where there were still many fine particles. VITO replied that these measurements were taken not as a reference but simply to obtain several values to be able to differentiate between the peak and the average.
- It was noted that similar measurements taken 7 kilometres away from Schiphol airport revealed much higher UFP concentrations than around Brussels airport. According to experts, a longer-term study was under way at Schiphol, which also involved VITO. They felt that it was essential for the various airport regions facing the same air quality issues to share the results of their studies.
- The question was asked to link the UFP emissions that were measured to, for example, the fact that the aircraft there in certain locations generally fold out their landing gear. It was announced that when the landing gear is deployed the engines should give more power if the aircraft just needs to slow down further. That can lead to higher emissions. Brussels Airport wants to encourage airlines even more to expand the landing gear as late as possible.
- The question was asked whether the very significant increase in aircraft taking off from runway 25L would have an impact on air quality in Zaventem. The VITO expert explained that UFPs did not fall to the ground because they were ultra-fine and were carried by the wind.
- One of the participants asked whether UFPs had an impact on the gardens and allotments of the municipalities bordering on the airport. According to the experts, this was not the case because UFPs behaved like a gas. In other words, these particles remained in the air and did not settle on the ground.
- Another participant was concerned that the UFP measurements were carried out in October and November, which are very windy months, and this might have skewed the results. According to the experts, as the measurements were taken over two months, the results were sufficiently representative.
- One of the participants regretted that the Strategic Vision did not pay more attention to road traffic pollution, which had a much higher impact than pollution from aircraft. The Tractebel expert said that the growth in road traffic had indeed been taken into account in the calculations.
- During the discussion, it also emerged that the air quality studies were based on very conservative scenarios. For instance, they took no account of the positive effects of biofuel use (which is expected to increase in future) or of the positive impact of electric taxiing and other new technologies.
Suggestions for Brussels Airport Company
- Several participants asked the experts and Brussels Airport Company to carry out air quality measurements over a longer period, as was already the case at Schiphol, but also over a wider geographical area.
- Several participants also called for a combination of measurement and modelling to achieve even more representative results.
- The question was asked to extend the VITO study and for the route of runway 25L also to be considered. One also asked for reference measurements be taken into account that were further than 7 kilometres away from the airport.
- Several participants suggested asking Flemish universities to study the effects of UFPs on health to obtain some reference points.
- One suggested looking at the measurement results for the week following 22 March 2016 to see what the airport's major impacts were apart from ultra-fine particles.
Suggestions and thoughts about ground noise
Several participants commented on the very conservative bases of the KU Leuven calculations:
- One asked the KU Leuven expert why he had stated during his presentation that he had used a "worst-case scenario". The expert replied that he had indeed used extremely cautious calculation criteria. Two examples: no account had been taken of the noise reduction expected from new-generation aircraft engines or electric taxiing.
- Other participants were surprised that the KU Leuven study did not take account of developments and innovations in aircraft engines, for example. The expert replied that the impact of changes that were made over the years was difficult to predict. He had therefore opted for a conservative scenario. A participant also confirmed that technological developments happens over a period of years rather than suddenly.
- Someone gave the example of aircraft which, when taxiing to the gates, often used only one engine. This reduces ground noise and fuel consumption.
- Someone stated that when embarked on a more detailed phase of the study, the real situation, that would probably have evolved in the meantime as a result of technological progress, will be taken into account.
Other participants commented on the factors considered in the study.
Other participants commented on the factors considered in the study.
- One participant regretted that the KU Leuven study had been restricted to showing a ground-noise contour based on a 50 dB limit. This participant said that recent studies indicated that noise would already have an impact on health from 40 dB, specifically learning difficulties in children. The KU Leuven expert replied that he was not qualified to comment on health issues.
- Another participant was surprised that the various impact studies on noise, whether aircraft- or ground-related, were always based on a night lasting until 7 a.m., while the restrictions on the number of night-time movements at Brussels Airport stopped at 6 a.m. This participant claimed that the impact of this time between 6 a.m. and 7 a.m., when there were many take-offs and therefore a lot of ground noise, was mitigated in the figures presented by KU Leuven. According to the expert, however, this period was clearly visible in the results of his study.
- Some participants wondered whether it might be possible to take additional measures to reduce ground noise, for example by using less noisy tarmac or by adding plantations near the airport gates and buildings. According to the KU Leuven expert, the impact of this type of measure would be minimal, however.
- One participant asked whether it would be wiser to publish figures combining the impacts of ground noise and aircraft noise. The expert considered that there would be no point in combining them because the two types of noise were too different.
Several participants regretted that the study presented averages only, whereas it was the peaks that had a significant impact on the quality of people's lives. Other participants agreed with this point of view. One participant also insisted that the impact of noise was different depending on whether it occurred during working hours or at a time when people wanted to rest.
- A Brussels Airport representative said he understood that the measurements could raise many questions. Especially since, for the moment, this is still a vision rather than a specific plan. However, it is important for the airport to measure the potential impact of its vision, taking the present situation into account. A local resident emphasised that the BAC initiative was still very interesting. He would like the studies carried out to take specific account of the peak times and the time slots between 6 and 7 a.m., so that the results presented tallied properly with the experience of residents.
Suggestions for Brussels Airport Company
- As requested for aircraft noise, several participants asked if it would be possible to have studies showing the impact of ground noise at peak times and between 6 and 7 a.m.
Suggestions and thoughts on spatial planning
A representative of BAC emphasised that there was still no spatial planning policy. No action had been taken in that direction. This representative, like other participants, was surprised that houses were still being built just hundred metres from the runways, where planes take off every two minutes. One mayor insisted that he informed future residents of the situation but that the decision must come from the Flemish Region. All participants agreed on the importance of having a stable framework as a basis for a clear spatial planning policy.
- One participant asked if the noise barriers would still be 18 metres high. The Arcadis expert replied that it depended on the relief of the terrain. On the south side, for example, the walls would be only 8 metres high on average.
- One participant wanted a noise barrier to be built also on the Zaventem side.
- Several participants asked why the Arcadis study was based on noise barriers that were straight on the inside and sloping on the outside, while so far, the opposite option had been chosen for some noise barriers already built (specifically in Steenokkerzeel). According to the Arcadis expert, noise barriers could be of many types, but the type with an outside slope often blended better with the landscape and did not look so much like the “Berlin wall” or “Mexican border wall”.
- A representative of Brussels Airport Company stressed that various options could be developed.
- In answer to a participant concerning the impact of the existing noise barrier in Steenokkerzeel, a representative of Brussels Airport said that it had genuinely reduced ground noise for residents.
- One participant was concerned about the impact of the proposed options on farmland. She pointed out that some of this land, which was regarded as strategic by the Flemish Brabant province, might be cut off from the farming land to the south if Option B were chosen. She therefore asked that the impact on agricultural land be properly mapped, with a small impact study as well. Another participant pointed out that the issue of compensation to be given to farmers would have to consider these impacts, otherwise these farms would have to close down. According to the expert, a legal framework would have to be established.
One participant insisted that more account should be taken of the viability of the land around the airport. He found this aspect missing from the studies presented. Specific figures showed that 22 houses would be directly impacted. It was a very limited impact. On the other hand, spatial planning would have a greater impact on the viability of neighbourhoods around the airport. One local resident gave the example of the impact of the noise barrier on the quality of life in certain neighbourhoods.
According to several participants, one solution among others for limiting the impact of ground noise is to invest in the insulation of homes. But several speakers pointed out that this was not a panacea since, in summer, people liked to spend time in their gardens. One participant also noted that funds to insulate houses were and would be available for homes located close to the airport. On the other hand, they would not be available in the municipalities that were further away from the airport but also suffered from noise pollution.
A participant expressed reservations about the definition of "heritage value" and argued that, if the definition were changed, more buildings could be considered affected. The expert explained that the definition used was taken from the current Flemish decree.
Suggestions for Brussels Airport Company
- Why not use the slopes of the noise barriers for useful things? The suggestions included: vineyards, sports halls and mountain bike trails.
- A participant asked to further study and take into account the quality of life for those whose homes are not impacted by the extension or placement of a noise barrier, but who live in its immediate surroundings. One participant asked for the full Arcadis report to be made available to Forum 2040 members.
- One participant asked if someone could be invited who had researched this topic around the airports of Liège and/or Charleroi.
- Another participant asked if it was possible to install a noise barrier along Felix Timmermanslaan in Diegem.
- A request was also made in favor of a noise barrier in Zaventem (center).