Many cities around the world suffer from excessive air pollution. Sources such as road traffic and industrial plants cause high concentrations of fine dust and nitrogen dioxide. In Germany and other countries, the violation of limit values, in particular with regard to nitrogen dioxide, is continually a point of discussion. Busy roads are especially affected by high emission values, but pollution in underground railway stations from fine dust is also high. Many city residents are continually exposed to polluted air.

Where fine dust is particularly dangerous

  • There is substantial air pollution at locations with busy road traffic or high emissions from chimneys where the exchange of air is low. This leads to problems with nitrogen oxides and violations of the fine dust limit values. Due to this, local authorities are now exposed to the risk of legal action.
  • Fine dust pollution is particularly relevant at particular locations within cities. Very often, these higher emissions can be found at points where more people tend to be. This is true for large road junctions, railway stations, bus stops, or underpasses. The risks to health at these locations are especially high.
  • For certain groups, the risks from pollutants are above average. People with respiratory diseases, elderly people, or children should not be exposed to increased concentrations of fine dust or nitrogen dioxide.
  • Clean air is a basic requirement for quality of life. Wherever people study, work, shop, or spend their leisure time, they want to be surrounded by clean air. No one wants to be concerned about fine dust values.


Our approach

MANN+HUMMEL has set its sights on poor air quality at so-called hotspots. In places with heavy traffic or heavy emissions from chimneys and low air exchange, air pollution is particularly high. People who regularly spend time here - such as at major intersections, train stations, or underpasses - have a particularly harmful effect on their health.

The filtration expert knows all about how to clean air. For decades, the company has been well known for its filters used in vehicles or buildings. Now, we are transferring our filtration expertise to help reduce air pollution at urban hotspots. Using stationary filter systems such as our Filter Cube, we are able to reduce the pollution levels at the respective location and make a contribution to protect health. Filters installed in filter columns reduce the local concentration of fine dust and nitrogen dioxide. Our technology can also be integrated in billboards for bus stops or railway stations.

Filter Cube

The MANN+HUMMEL Filter Cube is able to bind more than 80 percent of the NO2 and fine dust contained in the ambient air that is drawn in. The core of the technology is a newly developed combi filter. This includes a filter layer that retains particles and additional activated carbon layers to adsorb NO2. In this process, these highly porous activated carbon media absorb NO2 very effectively due to their large surface area.

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. Depending on the requirements, using a modular system means a number of Filter Cubes can be installed on top of each other to form a filter column. A filter column with three further developed Filter Cubes is able to clean 14,500 m³ of air every hour. Control electronics allow the user to adapt the operation of the filters to match operating conditions and therefore react to the current air quality. Integrated sensors record air and weather data which are transferred to a cloud and analyzed.


Fine dust filters at the Stuttgart Neckartor

  • The Stuttgart Neckartor has one of the highest levels of fine dust pollution in Germany. In recent years, this area and its associated measurement station has garnered negative fame for recording values which continually exceeded the permissible limits. Supported by the city of Stuttgart and funded by the Ministry of Transport of the state of Baden-Württemberg, MANN+HUMMEL is now conducting a pilot project to test the use of fine dust filters in this area.
  • The project partners have installed 17 filter columns, so-called Filter Cubes III, which MANN+HUMMEL has recently developed, along a 250 meter stretch of road at the Neckartor road junction in Stuttgart. The filter columns each include three fine dust particle filters and fans which draw in ambient air.
  • The first assessments of the project 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 percent, which corresponds to 40 percent of all fine dust particles caused by heavy traffic at the road junction.



Who started the initiative?

MANN+HUMMEL approached the state of Baden-Württemberg and the city of Stuttgart. The company has been an expert in the filtration of liquids and air for more than 77 years, and last year set up the Fine Dust Eater technology platform. The platform includes stationary and mobile filtration solutions which can be used to reduce fine dust pollution in cities.

How do the filter columns work?

Fine dust particle filters and fans are integrated in the Filter Cubes. The fans draw in surrounding air and the filters retain the fine dust that is present in the drawn in air. The fans are programmed only to function when required in order to minimize the consumption of energy. In addition, integrated sensors collect data on the air and weather.

How big are the filter columns?

A Filter Cube III is 3.6 meters high. Three individual Filter Cubes are installed on top of each other in a modular system. These each have a width of nearly one meter.

Has the effectiveness been verified?

The project is currently in the test phase. An independent simulation office has made model calculations for the effectiveness of the installation at the Neckartor traffic junction. These simulation results show that the overall fine dust pollution can be reduced.

The first assessments of the project 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 percent, which corresponds to 40 percent of all fine dust particles caused by heavy traffic at the road junction.

How long will the project run?

The pilot project is planned to run for two years.

Why was the Neckartor chosen?

The Neckartor was chosen as it is the location with the highest fine dust pollution in Stuttgart.

Is the installation of filter systems also planned for other locations?

MANN+HUMMEL has primarily developed the Filter Cubes for use at locations where there is a high level of air pollution and where there are also many people. They can make a contribution towards protecting persons passing by. Filter Cubes are already in operation at the Bleyle complex and in front of the company premises of MANN+HUMMEL, both in Ludwigsburg.

In the course of 2019, the technology will also be used in the Friedrichstrasse in Ludwigsburg. Here, the limit values for nitrogen dioxide have been exceeded in recent years.

The filters are more effective in closed or semi-closed environments such as bus stops and railway stations.

Three Filter Cubes II for the Bleyle complex

  • The Bleyle complex in Ludwigsburg includes a school, kindergarten, a medical center, and companies. People live, work, and study here. The many busy roads and a railway station in the area contribute to numerous sources of fine dust.
  • The complex was built by the construction company WOLFF & MÜLLER. Now the company would like to offer people the best possible air quality at the location and has opted for the Filter Cubes developed by MANN+HUMMEL. Sustainability is important for the building contractor who builds with a neutral CO2 balance. The subject of avoiding fine dust pollution is also very relevant for the company.
  • WOLFF & MÜLLER would like to use the Filter Cubes from MANN+HUMMEL to make a contribution to protect people against fine dust. Since October 2018, the two companies have been testing three Filter Cubes II from MANN+HUMMEL in the Bleyle complex. The aim of the joint project is to reduce fine dust pollution and improve air quality.

Contact Persons

Thomas Michalak
Sales & Business Development Manager - Public Air Solutions
Laura Montag
Manager Corporate Relations