Since December 2018, a pilot project for air filtration has been under way in the Stuttgart area Am Neckartor, involving the state of Baden-Württemberg and the city of Stuttgart. Executor of this Project is the Ludwigsburg-based company MANN+HUMMEL.
An accompanying scientific study has now shown that nitrogen dioxide and particulate matter PM10 in the ambient air can be significantly reduced with the air filter columns. The investigations clearly show that the so-called Cubes filters lead to an improvement of the air quality. On average, a reduction of 9 percent of the nitrogen dioxide load, i.e. 4-5 µg/m³, is achieved, while a reduction of 10 to 19 percent can even be observed in the vicinity of the pavement and close to the buildings. Investigations focusing on particulate matter PM10 showed an average reduction of over 10 percent. MANN+HUMMEL has now published the final report of the extensive investigations, from which the individual results can be seen.
Transport Minister Winfried Hermann MdL: “Thanks to a variety of measures, air quality has improved. The combination of these measures is essential for adhering to the immission limit value. The air filter columns at Stuttgart’s Neckartor contribute significantly to the fact that this measuring station is no longer one of the measuring stations with the highest pollution levels in Germany. I believe this is a great success.”
Jan-Eric Raschke, Director & Chief Product Owner Public Air Solutions at MANN+HUMMEL, explained: “With these studies, we have scientifically proven that our Filter Cubes significantly reduce harmful gases such as NO2 and fine dust at hotspots. We are delighted that our innovative filtration technology can contribute to the protection of Stuttgart's residents and visitors.”
Transport Minister Winfried Hermann: “Air filter columns are a technical contribution to defuse locally limited problem areas. At the beginning of the pilot project, we said that we would spare no effort when it comes to achieving cleaner air.”
The Ministry of Transport relies on sustainable forms of mobility and innovative technologies to ensure the fastest possible and permanent adherence to limit values. This primarily includes low-emission and regulation-compliant vehicles, greater and better public transport, intelligent traffic control and better conditions for cyclists and pedestrians.
Air filter column technology has proven itself as a measure for inner-city hotspots. Air filter columns improve the air quality in the three corresponding road sections in Stuttgart. Since July 2020 such columns are also operated in Heilbronn, Weinsberger Straße. The air filter columns used by the state government are designed for use in particularly highly polluted road sections. The Filter Cubes are generally free-standing, integrated at stops or used in advertising or information boards.
The state government’s measures are effective: in 2019, the permitted annual average value for nitrogen dioxide (NO2) of 40 µg/m³ was only exceeded in four cities in Baden-Württemberg. In 2018, it was still 14 cities. In 2017, it was 17 cities.
Final report: Filtration pilot project at Am Neckartor in Stuttgart
The immission limit values for nitrogen dioxide (NO2) and PM10 fine dust as well as the obligation to adhere to these arise from the Air Quality Directive of the European Union (Directive 2008/50/EC) and its implementation in national law within the framework of the Federal Immission Control Act (BImSchG). The limit value for PM10 fine dust amounting to an annual average of 40 µg/m³ has been adhered to across the board in Baden-Württemberg since 2011; the limit value for PM10 fine dust amounting to a daily average of 50 µg/m³ with 35 permissible exceedances in the calendar year has been adhered to since 2018. The limit value for nitrogen dioxide amounting to an hourly average of 200 µg/m³ with 18 permissible exceedances in the calendar year has been adhered to across the state since 2017. The limit value for the annual average of nitrogen dioxide amounting to 40 µg/m³ was only exceeded in four cities in Baden-Württemberg in 2019.