Under “FAQs” you can find an overview of the key topics in the debate about nitrous gases.
Nitrous gases is a term that refers to the gaseous oxide compounds of nitrogen, nitrogen monoxide (NO) and nitrogen dioxide (NO2). Because there are several compounds of nitrogen and oxygen, these gases are also known for short as NOx. These gases arise when fuel is combusted in an engine. In contrast to carbon dioxide (CO2), which is harmful to the climate, a high concentration of NOx gases can have a direct impact on human health. Nitrogen dioxide (NO2) is particularly dangerous in this respect.
The main cause of NO2 pollution is traffic on the roads. A good half of the NO2 pollution that comes from motorised transport is caused by diesel-powered cars and lorries. In real driving conditions, diesel cars emit much more NO2 than was claimed by the manufacturers. Public buses on roads with a lot of buses are a further significant source of nitrous gases.
In Berlin, as in many other German cities, levels of NOx gases are too high. The sections of road with the highest levels of pollution are to be found in: Leipziger Straße, Potsdamer Straße and Hauptstraße, Wilhelmstraße, Brückenstraße, Tempelhofer Damm and Mariendorfer Damm. However, the limit value for NOx gases was sometimes significantly exceeded at almost all of the 29 measuring stations along roads with high volumes of traffic.
The problem of high levels of nitrous gas pollution is not restricted to the areas around the measuring stations. This is shown by the results of recent simulations carried out to calculate air pollution for the entire 1,600 km of main roads in Berlin. These calculations were made on the basis of the latest data regarding traffic volumes, frequency of congestion, a breakdown of traffic according to vehicle type and the emissions of these vehicles.
The calculations show that limit values were exceeded along almost 500 sections of road with a total length of 60 kilometres. Moreover, these high levels of pollution are caused overwhelmingly by motorised traffic and, above all, by diesel vehicles.
Current projections assume that in 2020 limit values will still be exceeded along approximately 20 sections of road totalling five kilometres.
In particular, the respiratory system is affected. Asthma sufferers in these polluted areas complain about worse symptoms. Moreover, people who do not suffer from asthma but who are exposed to high levels of nitrous gases can suddenly begin to experience respiratory problems from one day to the next. In Berlin, there are about 200,000 adults and 50,000 children with asthma. High levels of NO2 mean that all of them experience more frequent and more severe asthma attacks. They also have a greater need for medication and have to consult a doctor more frequently. Asthma is just one example of the impact of NO2 on human health. This form of pollution can also lead to coronary and circulatory illnesses.
Pollution levels must be kept below the applicable limit values in order to protect the health of the Berlin public. Furthermore, because Berlin is currently exceeding these limit values, it is affected by the infringement proceedings of the EU Commission. Finally, citizens and environmental bodies have taken legal action before Berlin’s administrative court to enforce adherence to these limit values.
Berlin is trying to protect the health of its citizens with an extensive package of measures. At the same time, it is seeking to plot a course towards more climate-friendly and sustainable forms of mobility. The Senate plans to reduce pollution caused by nitrous gases with the help of ten immediate measures. These measures include support programmes for taxis and business-friendly e-mobility which aim to get many older diesel vehicles off the road as quickly as possible and to replace them with environmentally friendly alternatives. The package also includes replacing vehicle fleets owned by the federal state of Berlin with electric vehicles, making retrofit offers for vehicle types for which there isn’t a fully electronic alternative, expanding the charging infrastructure, adopting immediate measures for areas exposed to high levels of nitrous gas pollution, making public transport more attractive, promoting cycling, increasing the numbers of electric vehicles offered by car sharing services and demanding a Germany-wide retrofit for diesel cars.
When cars and, above all, diesel vehicles accelerate less, and the flow of traffic is more even, this creates fewer nitrous gas emissions. Reduced speeds on the road and adjustments to traffic light cycles are suitable ways of achieving an even flow of traffic on Berlin’s roads with as few stops and as little acceleration as possible – in other words of improving the flow of traffic. The pilot test underway along Leipziger Straße and four other sections of main roads with high volumes of traffic is trying to establish if traffic flow can be improved by a 30 km/h speed limit and adjusted traffic light cycles and how a reduction in stop-and-go traffic affects air quality.
A 30 km/h speed limit was introduced and enforced along Schildhornstraße in Steglitz. As a result, it was possible to reduce additional local pollution caused by motorised traffic by 30 per cent in the case of particulate matter and by 15 per cent in the case of nitrogen dioxide. This corresponds to a reduction in the overall level of pollution along Schildhornstraße by approximately five to ten per cent. The introduction of a 30 km/h speed limit in Beusselstraße in Moabit and in Silbersteinstraße in Neukölln yielded similarly positive results.