Environmental terms

STRzero is the name of the carbon strategy for the Baden-Württemberg regional airport. The STRzero carbon strategy includes , amongst other things, the airport operator’s emissions reduction target.

The Energy and Climate Master Plan is an action plan that sets out the steps required for the state airport to comply with the Baden-Württemberg Climate Protection Act. It therefore forms the basis for STRzero. The Energy and Climate Master Planis updated regularly.

Emissions refer to the release of substances – usually in the form of gases or particles – into the environment. When it comes to the climate, the term ‘emissions’ refers to the release of greenhouse gases into the atmosphere.

Emissions can be categorised according to their source and composition:

• Greenhouse gas emissions:Theseinclude carbon dioxide (_CO₂), methane and nitrous oxide. They are produced primarily by the combustion of fossil fuels.
• Pollutant emissions: These include nitrogen oxides , particulate matter and sulphur dioxide.
• Noise emissions: These refer to noise from machinery, vehicles and traffic.
• Heatemissions:Waste heatgenerated, for example, by the combined heat and power plant at the airport.

Carbon dioxide (CO₂) is a gaseous compound consisting of carbon and oxygen. It occurs naturally in the atmosphere. If its concentration rises – for example, as a result of human activities – this intensifies the greenhouse effect, which leads to global warming. CO₂ is produced, for example, during respiration and during the combustion of hydrocarbons such as petrol, natural gas or kerosene.

The landing and take-off cycle, or LTO cycle for short, has been established as an international standard by the International Civil Aviation Organisation (ICAO). It is used to calculate local, traffic-related emissions. This refers to all aircraft movements below 3,000 feet (just under 1,000 metres) in the vicinity of the airport. The cycle is divided into the following phases: landing, taxiing, handling, re-taxiing, take-off and climb. Fuel consumption is determined for each phase in order to calculate the resulting greenhouse gas emissions.

TOC stands for Total Organic Carbon – it indicates the proportion of organic carbon in a sample. This can be used, for example, to determine the extent to which water is contaminated with foreign substances.

At the airport, de-icing agents are used on aircraft and runways in winter. These contain carbon, which is, however, readily biodegradable. The contaminated water is pre-treated in a floating-bed reactor with the help of bacteria. It can then either be discharged to municipal sewage treatment works or – if suitable – discharged into surrounding water bodies. An online monitoring system checks whether the water quality is good enough: the TOC value must be below a certain threshold.

CO₂ emissions are produced when materials such as oil, coal or wood are burnt. This releases carbon dioxide, which accumulates in the atmosphere. Stuttgart Airport tracks not only CO₂ but also all other greenhouse gas emissions it generates. These are convertedinto CO₂ equivalents (_CO₂eq).

This means that the quantity of a greenhouse gas is converted into the equivalent amount of CO₂ that has the same impact on the climate.

Greenhouse gases are gases such as carbon dioxide, nitrogen oxides, hydrocarbons and methane. They occur both naturally and as a result of human activities. If their concentration increases, this leads to global warming. At the airport, these gases are produced primarily by the combustion of fuel in vehicle engines and aircraft engines.

Net greenhouse gas neutrality, or‘net zero’, means that a balance is achieved between greenhouse gas emissions and the amount removed from the atmosphere.

It is important to note that emissions should, first and foremost, be avoided or reduced. They may only be offset where this is not technically feasible – in other words, the same amount of carbon dioxide must be removed from the atmosphere as was emitted.

Stuttgart Airport is guided by the Baden-Württemberg Climate Protection Act, which sets a target of net greenhouse gas neutrality by 2040. For the airport operator, ‘net zero’ means, as a first step, reducing its Scope 1 and Scope 2 emissions as far as possible through appropriate measures. The company has developed the technical solutions for this in itsEnergy and Climate Master Plan.

Ultrafine particles are produced during combustion processes involving very high temperatures – for example, when smoking tobacco, when candles are burning, or in engines such as aeroplane engines. They are found in the air around the airport as complex mixtures in varying concentrations.

An aircraft movement is the take-off or landing of an aeroplane.

The sound pressure level measures the intensity of a sound event.

The continuous sound level helps to assess noises whose volume varies over a period of time or is interrupted by pauses. The individual sound level values are combined to form a comparative value. This value takes into account the intensity, duration and frequency of the individual sound events.

Aircraft noise reports

The noise protection zone describes the classification of the immediate surroundings of a commercial airport in accordance with the German Aircraft Noise Act. These are:

• Daytime Protection Zone 1: Continuous sound level from 65 dB(A)
• Daytime protection zone 2: Continuous sound level between 60 and 65 dB(A)
• Night-time protection zone: continuous sound level of 55 dB(A) or above and at least 6 peak levels exceeding 57 dB(A)

Decibel (dB) is a unit of measurement for acoustic measurements such as sound pressure level. The A in dB(A) stands for the A-weighting filter. This A rating takes into account how humans perceive different sound frequencies at different volumes and adjusts the measured values accordingly.

The maximum sound level is the highest sound pressure of a single aircraft noise event. When an aircraft flies overhead, the sound pressure level initially rises, reaches its maximum value at the shortest distance from the measuring microphone and then drops again. The maximum noise level is not calculated, but is displayed directly as a peak value during measurement.

The microphones at the outdoor measuring stations record all ambient noise around the clock. These noises are stored as a sound level-time curve.

Potential aircraft noise events are defined as all recordings with a maximum sound level above 60 dB(A) lasting between 5 and 90 s. To ensure that the noise is indeed aircraft noise, the recordings are compared with the radar tracks of the aircraft. Only if an aircraft is in the vicinity of the measuring point at the same time is the noise classified as aircraft noise. This rules out other sources of noise such as church bells or construction sites as the cause of the event.