Airports bring many benefits, not least job creation, trade, and tourism, but they can also have a detrimental impact in terms of noise. Its control is therefore crucial to their development.
Although aircraft manufacturers and airlines have significantly reduced noise emissions in recent years, the World Health Organization (WHO) estimates that approximately four million of the European population are exposed to levels harmful to health.
The increase in air travel also plays a part in this. According to the current European Aviation Environmental Report (2022) from the European Union Aviation Safety Agency (EASA), the number of flights at EU member state and European Free Trade Association airports increased by 15% between 2005 and 2019, reaching 9.3 million. Passenger kilometres almost doubled (+90%) in that period, and we are currently seeing a post-pandemic return to travel that is driving flight numbers back to 2019 levels.
Managing director Jochen Schaal
People who live in the immediate vicinity of an airport must be given special protection as numerous studies show that long-term exposure to noise can cause a variety of adverse health impacts. These include annoyance, sleep disturbance, negative effects on the cardiovascular and metabolic system, as well as cognitive impairment in children. In fact, according to WHO findings, noise is the second largest environmental cause of health problems, after the impact of air pollution.
Studies show that long-term exposure to noise can cause a variety of adverse health impacts
There are direct monetary impacts from these health repercussions too. For some years, analysis focused on the diminished value of property in very noisy areas, which is rightly a key consideration. It is now recognised that this constitutes a fraction of the financial repercussions. The resulting expenditure from medical effects (such as cardiovascular diseases or hearing impairment), plus the cost of reduced children’s learning ability is now also taken into account. This makes taking noise precautions in the planning of new infrastructure developments, and noise remediation in already highly polluted urban areas, all the more important.
A 3D noise map of an airfield with flight paths and corridors
Aircraft noise level guidance
To mitigate adverse effects from aircraft noise on citizens’ health, the WHO recommends reducing aircraft noise levels below Lden 45dB and Lnight 40dB. Lden is an average sound pressure level over all days, evenings and nights in a year. Lnight is the equivalent continuous sound pressure level when the reference time interval is night-time.
However, EASA reports that at 98 major European airports during 2019, 3.2 million people were exposed to Lden 55dB aircraft noise levels and 1.3 million people were exposed to more than 50 daily aircraft noise events above 70dB. This is 30% and 71% more than in 2005 respectively, according to its analysis.
Noise mitigation solutions
In its Zero Pollution Action Plan, the European Commission has proposed a policy target of reducing the share of people chronically disturbed by transport noise by 30% by 2030.
There are various solutions to mitigate aviation noise pollution. These include reduction of noise at source in aircraft design, and land-use planning and management to minimise the population affected by aircraft noise. Analysis and noise control for landing sites, and control of noise by measuring and calculating flight routes can also be undertaken.
The International Civil Aviation Organization (ICAO)’s ‘Balanced Approach’ to aircraft noise management is the main overarching policy. The principle of the Balanced Approach entails identifying mitigation measures through four aircraft noise management pillars, and then analysing them with the goal of addressing the problem in a cost-effective manner that preserves the connectivity benefits at the airport.
The four pillars of the Balanced Approach are: reduction of noise at source; land-use planning and management; noise abatement operational procedures, and, at last resort, operating restrictions.
Austria is following the ICAO’s Balanced Approach policy on mitigating aircraft noise
Noise mapping
Modern noise mapping programmes make it possible to model complex situations – such as multiple flight paths onto a number of runways, along with traffic to and from the airport – and to use them to assess nuisance noise and plan mitigation measures. This means noise reduction measures can be planned and their effectiveness assessed using the mapping software.
The simulation software develops a model from data sources and produces graphical representations of emissions using colours to depict the different levels. This makes the information accessible to the general public as well as scientists and engineers. Each noise map is unique according to project size, geography, and objective.
Noise mapping software enables airports to not only show current levels of noise but can also predict future levels and sound dispersion for planned flights, which is vital for future development. The maps can then be used by airports to plan mitigation efforts and show improvements in an easy-to-understand format. Conversely, planning authorities can use the maps to show if the impact of a new airport or expansion would be too much for an area to handle.
A noise map of Vienna International Airport (Lden) with OpenStreetMap
International standards
National and international aircraft acoustics standards are incorporated into noise mapping software. For example, in Germany the AzB or Anleitung zur Berechnung von Lärmschutzbereichen (instructions for the calculation of air traffic noise) standards apply. The AzB:2008 consists of a calculation regulation and the noise source data for certain aircraft groups.
A recent milestone was the introduction of new harmonised standards for strategic noise mapping in Europe to improve the accuracy and comparability of results across the EU Member States. In accordance with Article 6.2 of the Environmental Noise Directive 2002/49/EC (END), the European Commission is developing Common Noise Assessment Methods (CNOSSOS-EU) for aircraft, road, railway, and industrial noise to be used for the purpose of strategic noise mapping.
The CNOSSOS-EU process is an ongoing procedure and will be modified appropriately in accordance with any future technical and scientific developments required for the successful implementation of the model. International standards are continuously developed in the relevant committees, whereby new noise findings are discussed. At the end of this process, test cases are developed to ensure these standards are implemented correctly to the different software products available on the market.
Vienna served 29.5 million passengers in 2023
An Austrian case study
During 2022 and 2023, SoundPLAN undertook a noise mapping project at six airports in Austria. The main hub analysed using the noise mapping software, SoundPLANnoise, was Vienna International Airport, which had a passenger volume of 29.5 million travellers in 2023. Other large metropolitan areas with high noise levels that were mapped were Klagenfurt, Graz, Linz, Salzburg, and Innsbruck.
At Vienna, calculations were based on radar tracking. Radar data is collected at fixed receiver points around the airport which are constantly monitoring the space nearby. The data includes the position of the plane (its height as well as its GPS co-ordinates), the type of aircraft and a time stamp. With this data, and using the mapping software, the speed and emissions from every aircraft flying in or out of Vienna can be calculated.
A noise map for night-time at Ankara airport
For the other Austrian airports, a hybrid approach was adopted. This included a combination of using radar tracks for all IFR flights (instrument flight rules) and geometrical model with generalised flight tracks for VFR flights (visual flight rules) for small aircraft and helicopters.
Each noise map is unique according to project size, geography, and objective
Using noise mapping software, flight track data and flight information can be imported, and noise levels calculated to ensure airports are meeting agreed noise levels. Data can be easily imported for different time periods, enabling effective comparison and assessment. Noise mapping software contains a vast library of information on flight profiles, including the types of planes and weight differentials, making the task much easier. It also incorporates different international noise standards, so that it can be used globally.
Noise maps based on radar tracks
Noise action plans
The Environmental Noise Directive requires EU countries to prepare and publish noise maps and noise management action plans every five years for major roads, railways, airports and built-up areas with more than 100,000 inhabitants. Noise mapping is the first stage of this process.
Following the strategic noise mapping, each Austrian airport will develop a noise action plan. These are incorporated as sub-action plans into the Environmental Noise Action Plan for Austria, completed in July 2024, under the review timeframe set by EU regulation.
This noise data also supports Austria’s long-term strategy for protection against aircraft noise following the Balanced Approach policy outlined by the ICAO.
Having systems to gather data and accurately monitor and map aviation noise is key. Mapping software can play a vital role in helping to plan future mitigation options and clearly demonstrate improvements. Addressing noise pollution enhances the reputation of airports and, above all, improves people’s lives.
According to the WHO, approximately four million of the European population are exposed to noise levels harmful to health
