University of Bayreuth, Press release No. 156/2021 vom 03 November 2021
Cleaner air in Munich? University of Bayreuth coordinates research project to improve air quality on busy streets
Funded by the Bavarian State Ministry for the Environment and Consumer Protection (StMUV), four Bavarian universities are investigating the effectiveness of air purification systems on the particularly polluted Landshuter Allee in Munich. Under the direction of the University of Bayreuth, the air on this congested part of the Mittlerer Ring is to be filtered and scrubbed of nitrogen dioxide (NO2). In the future, the filter systems could improve air quality in densely built-up and busy urban areas, and as such represent a flexibly deployable bridging technology.
According to StMUV, the existing limit concentrations of nitrogen dioxide were not exceeded at any of the measuring stations in Bavaria last year, except for one. Only at the "Landshuter Allee" measuring station was the existing air quality limit for nitrogen dioxide exceeded - despite a significant decrease in concentrations there as well.
The reason for this was the combination of the very high traffic volume of up to 140,000 vehicles per day, in conjunction with tight perimeter development influencing air circulation. In addition, locally specific effects, such as high emissions from the tunnel exit and from the diesel engines of the public transport buses servicing the nearby bus stop, could also be contributing to nitrogen dioxide concentration.
"Air filter systems could provide short-term relief as a bridging technology - until other measures take effect," says Prof. Dr. Anke Nölscher (Atmospheric Chemistry, University of Bayreuth). Together with Prof. Dr. Christoph Thomas, at the Micrometeorology research group of the University of Bayreuth, she is coordinating the research project. The scientific focus in Bayreuth is the investigation of atmospheric turbulence, air transport, and air quality along Landshuter Allee via high-precision measurements, supplementary laboratory experiments, and the use of model simulation. The effectiveness of the filter material itself is being investigated by the Laboratory for Combustion Technology of OTH Regensburg, while traffic density and composition along Landshuter Allee is being analyzed by the Traffic Engineering research group of TU Munich. Meanwhile, the real-world influence of the air filters on nitrogen dioxide concentrations along Landshuter Allee and in its immediate vicinity is being measured using a network of sensors installed by the Physical Geography research group of the University of Augsburg.
Prof. Dr. Anke Nölscher
The first seven of a total of nine air filter systems have now been erected along Landshuter Allee in Munich for the field test. "These systems are high-performance air filters that can be integrated into the roadway, where they filter a large volume of air at a high rate of throughput," explains Nölscher. "They can direct a total of over 130,000 m3 of air per hour over the absorbent materials involved, and in this way filter nitrogen dioxide, in particular, but also other pollutants, from the air."
The 3.6 m high air filters are mainly located in parking bays and on unused areas of the pavement, each consisting of three cubes placed on top of one other. Their effect is being studied on site and in laboratory and simulation studies with regard to weather conditions, nitrogen dioxide content, air flow, and traffic volume. The field trial on Landshuter Allee will be conducted over a period of two years. Data on air movement, air quality, and traffic will be recorded continuously. The aim is to test, for example, how the best filtering effect can be achieved under real conditions. According to Professor Nölscher, "We aim to develop scientifically-based recommendations for the deployment of such air filter systems in urban areas."