The 17 Filter Cubes III from MANN+HUMMEL installed at the Neckartor traffic junction in Stuttgart are being retrofitted with technology which now reduces the concentration of nitrogen dioxide in addition to fine dust particles. In the past, the limit value for nitrogen dioxide was regularly exceeded at the "Am Neckartor" measuring station.
In February, the filtration specialist had presented the technology for the reduction of nitrogen dioxide (NO2) at polluted locations at its company headquarters in Ludwigsburg. The innovation makes a contribution to protect human health and could remove the need for driving bans in inner cities. The Filter Cubes III from MANN+HUMMEL were installed at the Neckartor traffic junction at the end of last year to reduce fine dust pollution. The assessments made so far have shown that the filters could help to reduce the local concentration of dust particles by between 10 to 30%.
Equipped with a newly developed combifilter medium from MANN+HUMMEL, the Filter Cubes III at the Neckartor traffic junction in Stuttgart now retain nitrogen dioxide from the ambient air in addition to fine dust. The retrofit in question is a temporary solution to reduce the concentration of nitrogen dioxide as quickly as possible. In August, all 17 Fiter Cubes III will be replaced by further developed systems with a larger filter surface area and more powerful fans. In addition, MANN+HUMMEL will increase the total number of installations from 17 to 23. These measures will increase the impact compared to the temporary solution.
MANN+HUMMEL expects that the use of the filter cubes will lead to a reduction of between 10 to 30% for the local concentration of fine dust and also nitrogen dioxide. This corresponds to 40% of all the nitrogen dioxide and fine dust emissions which are generated by vehicles passing by the Neckartor traffic junction in Stuttgart. In the past, the limit value for nitrogen dioxide (40 micrograms per cubic meter on average throughout the year) was regularly exceeded at the "Am Neckartor" measuring station.
Less nitrogen dioxide through use of activated carbon
The newly developed combifilter includes a filter layer that retains particles and additional activated carbon layers to adsorb nitrogen dioxide. In this process, highly porous activated carbon media are used, and due to their large surface area, are able to efficiently absorb nitrogen dioxide. The pollutants are retained using a number of different processes, e.g. physical adsorption, chemical binding and catalytic reduction.
The technology is characterized by a particularly low drop in pressure. As a result, it is able to efficiently clean the air while using a low amount of energy. The Filter Cubes include combifilters and also fans to draw in the ambient air. The filters are able to bind more than 80% of the nitrogen dioxide and fine dust contained in the ambient air that is drawn in. Control electronics allow the user to adapt the operation of the filters to match operating conditions and therefore react to the current air quality. Sensors record air and weather data which are transferred to a cloud and analyzed.
Fine dust filters at the Neckartor traffic junction proven to be effective
In the course of a pilot project from MANN+HUMMEL, sponsored by the Ministry of Transport in Baden-Württemberg and supported by the state capital Stuttgart, 17 filter columns were installed at the Neckartor road junction in Stuttgart at the end of 2018. Since 2017, the measuring station at the location had repeatedly exceeded one of the three limit values for fine dust (number of times the PM10 daily mean value was exceeded). The pilot project is designed to investigate the extent to which the technology can be used to reduce the local fine dust pollution.
The first assessments of the project so far indicate that the Filter Cubes from MANN+HUMMEL make a considerable contribution towards the reduction of fine dust pollution. They reduce the local particle concentration by 10 to 30%, which corresponds to 40% of all fine dust particles caused by heavy traffic at the road junction.
The positive initial results regarding the fine dust filtration are similar for the effectiveness of the technology to reduce nitrogen dioxide concentrations. This has been verified by the results of simulations carried out by an independent engineering office.
Ludwigsburg also opts for Filter Cubes
In the fourth quarter of 2019, a project will start in Ludwigsburg where Filter Cubes are used with combifilters. On the basis of the company’s own calculations and a simulation carried out by an independent engineering office, MANN+HUMMEL has calculated that 23 filter columns will be able to demonstrably reduce the concentration of pollutants along Friedrichstrasse one of the main streets of Ludwigsburg. In recent years, the measurement station located there has exceeded the limit values for nitrogen dioxide. The filter specialists expect a reduction of 10 to 30% of nitrogen dioxide and fine dust along Friedrichstrasse.
Thanks to its decades of experience in filtration and its global production network, MANN+HUMMEL is able to implement the use of filter cubes in further polluted locations in just a few months. By using this technology, municipalities threatened by driving bans have the opportunity to achieve a rapid improvement in air quality. By using several filter cubes, an area-wide effect is achieved on site and comparatively little installation space is required.
The use of filter columns around the world is useful wherever people are particularly exposed to nitrogen dioxide and fine dust pollution. This applies, for example, to roads with high traffic volumes and large road junctions. Further areas of applications could include bus stops or underground railway stations. MANN+HUMMEL is also developing filtration concepts which can be directly integrated in bus stops or installed in the form of advertising or information panels.
Further new developments from MANN+HUMMEL, such as the brake dust particle filter and fine dust particle filter, help to improve the overall emission balance of vehicles. MANN+HUMMEL also offers highly developed combifilters for the interior of vehicles, which protect the vehicle occupants against particles and gases. Now, the company has expanded its expertise in the area of activated carbon to the reduction of nitrogen dioxide in the ambient air.