For the year 2015, NO2 values above 40 µg/m3 were calculated along 492 road sections with a total length of approx. 60 km.
The most severely polluted road sections are located along Leipziger Straße across Potsdamer Straße and Hauptstraße, along Reinhardstraße and Wilhelmstraße, along Brückenstraße and Friedrichstraße in Mitte, Tiergarten and Schöneberg. Hermannstraße in Neukölln, too, lies well above 50 µg/m3, as do many other road sections. Measuring more than 70 µg/m3 and in some sections even more than 90 µg/m3, Leipziger Straße is Berlin’s most heavily polluted street. The annual average limit to protect human health is 40 µg/m3.
The large number of buses contribute significantly to the increased NO2 values. Whereas the diesel soot emissions of the Berlin buses were reduced by more than 90 % by retrofitting them with particulate filters, there is still potential for reducing the nitrogen oxide emissions. Retrofitting with systems for nitrogen oxide reduction of regular buses with the exhaust emission standards Euro IV and Euro V is already being carried out. Moreover, for new acquisitions, the exhaust emission standard Euro VI is mandated. It also has to be demonstrated that the intended reduction in emissions is also effective in urban traffic. First successes have already manifested at Hardenbergplatz. In 2016, the measurement station installed there measured NO2 concentrations lower than in the previous years.
Along Leipziger Straße and Potsdamer Straße, the motor vehicle traffic and the still rising share of diesel vehicles as well as the insufficient effectiveness of the NO2 reduction systems are mainly responsible for the increased values. It is assumed that without a change in legislation or tax subsidies, the proportion of diesel vehicles in Berlin will be above 50 % in 2020. In that case, only a decrease in traffic volume and a significant reduction of the proportion of trucks would lead to compliance with the NO2 limits in 2020.
Summary
It has turned out that the Berlin NO2 pollution in residential areas and along primary roads did not decrease as much as had been predicted with model calculations between 2009 and 2015. The reasons for this include the significantly higher emissions of newer diesel vehicles with the Euro 5 and 6 norms during actual operation. They not only lie far above the limit of the respective Euro norm to be adhered to in the laboratory but also significantly exceed the emission factors of Version 3.1 of the UBA manual that the calculations in 2009 were based on. In the meantime, the manual has been updated based on new information about the actual emissions, particularly of vehicles with the exhaust emission standards Euro 5 and Euro 6, which are significantly higher than predicted in 2009. Based on these improved emission factors and newer insights into Berlin’s fleet composition, the calculation of the NO2 pollution along Berlin’s primary roads was repeated for the year 2015.
The numbers of residents affected by NO2 limit value exceedance in 2015 are being corrected based on the new calculations. Whereas in 2009 it was predicted that in 2015 approx. 30 km of primary roads and that in 2020 no road sections would exceed the NO2 limits, the newer calculations have shown that in 2015 Berliners were still exposed to excessive NO2 pollution along 60 km of road sections.