According to figures estimated by the World Health Organization, particulates are responsible for the death of around 47,000 people every year in Germany. As a filtration company which carries out research, MANN+HUMMEL develops better, cleaner solutions for people and machines. Our current field test involves a test vehicle operating in the air-polluted city of Stuttgart.

In recent years public attention has been drawn to high levels of air pollution in cities in Europe. The harmful substances which contribute towards the air pollution include nitrogen dioxide and nitrogen oxides (NOX), sulfur oxides (SOX), carbon dioxide (CO2), carbon monoxide (CO), ammonia (NH3), volatile organic compounds (VOC) and ozone (O3). Particulate matter is especially harmful to human health. Small particulates (PM2.5) are able to penetrate deep into human lungs and may cause chronic lung and heart diseases.

Particulate matter is a mix of solid or liquid organic and inorganic substances. Natural sources such as volcanos, dust storms and forest fires are the cause of 90% of the particulates present in the air. Humans are responsible for the remaining 10%. Sources here are power plants, industry and households. Particulates are created in road traffic through the combustion of fuels and also through brake, tire and road abrasion.

The distribution and concentration of particulates depends on the weather and the immediate surroundings. The World Health Organization (WHO) has set guideline values for particulates. The annual average of these are 10 micrograms per cubic meter (µg/m³) for the finest particulates (PM2.5) and 20 µg/m³ for larger particles (PM10).
The WHO average daily guideline value is 25 µg/m³ for PM 2.5 and 50 µg/m³ for PM 10.

Health risk: fine dust

The Fine Dust Eater Project

In the public debate road traffic is blamed for a substantial part of the particulate emissions in a city. Accordingly, measures such as driving bans are repeatedly discussed. In these discussions the focus is mainly on exhaust emissions.
The particulate emissions of a vehicle, however, involve more than just the exhaust. Particles also enter the ambient air due to the braking process and also tire and road abrasion. These sources of particulates do not depend on the power train and are therefore also valid for electric vehicles. As a result, it is necessary to consider the overall balance of the particulate emissions of a vehicle.

MANN+HUMMEL, the filtration specialist from Ludwigsburg, has recognized this and for some time in the course of its R&D work has been carrying out field tests in the Fine Dust Eater project with test vehicles. The filtration experts have developed four applications which are designed to reduce the pollution caused by particulates. A filter installed on the roof of the vehicle retains particulates from the ambient air. A brake dust particle filter fitted to the brake system is designed to minimize the release of brake dust to the environment. The vehicle occupants are protected by an NOX fine dust combi filter. The vehicles have an eye-catching "Fine Dust Eater" (Feinstaubfresser) design which means they are hard to overlook as they make their test drives in the area of Stuttgart. Furthermore, stationary particle filters can also make a contribution towards the improvement of air quality.

Using many of these filters it would be possible to reduce the air pollution in a city caused by particulates. If more motor cars, commercial vehicles, busses, underground trains and suburban railways and also advertising pillars were fitted with the filters, more particulates could be filtered out of the ambient air.
This is particularly true for days when there is very high air pollution due to a high concentration of particulates. Vehicles which face the risk of driving bans could fit filters and therefore improve the overall balance in terms of particulates.


The use of 5000 StreetScooter delivery vehicles has so far enabled the Deutsche Post DHL Group to prevent considerable quantities of harmful gases such as carbon dioxide and nitrogen oxide as well as noise from entering the environment. Now the problem of particulates has been addressed. Equipped with a fine dust particle filter developed by MANN+HUMMEL, the StreetScooter Work is now the world's first emission neutral vehicle.

Electric vehicles also release particulates into the atmosphere due to tire, brake, and road abrasion and are therefore not free of emissions. Through use of the filter the overall balance of the vehicle in terms of particulates is now neutral. The fine dust particle filter retains as many dust particles as are produced by tire, brake and road abrasion.

The filter modules will initially be fitted to five StreetScooter test vehicles which with immediate effect will enter service in five German city centers. The successful completion of the test could lead to the series implementation of the fine dust particle filter.

The vehicle is completely neutral under consideration of the overall balance of emissions during driving operations: That means

• no carbon dioxide (CO2)
• no nitrogen oxide (NOx)
• no noise
• no particulates.

Mobile Fine Dust Particle Filter

The emissions in a city are produced by power stations, factories and households. Motor cars, transport vehicles, busses and railways also harm the environment and human health. These vehicles move around frequently in confined spaces during the day. If it were possible to improve the overall balance for the particulate emissions of these vehicles, it would also be possible to reduce the level of air pollution.

The MANN+HUMMEL fine dust particle filter enables vehicles to compensate for the emissions they release to the ambient air. When fitted, for example, to the roof or underbody of a vehicle, the filter can retain particulates present in the air. For this purpose, blowers convey ambient air into the system mounted at the vehicle. The filtration specialists use sensors and contact to a network cloud to record and assess the filtration performance and also collect air and weather data.
First tests indicate that the filter retains as many particulates from the ambient air as a vehicle with a modern gasoline or diesel engine emits in the combustion process.

Stationary Fine Dust Particle Filter

Air pollution is particularly high at locations where there is a high concentration of traffic or emissions from chimneys and a low exchange of air. If large numbers of people regularly frequent these places such as big road junctions, railway stations or subways, this can be especially harmful to their health. The installation of stationary fine dust particle filters at such locations can be used to improve the air quality.

MANN+HUMMEL is currently testing a filter column, it has installed in front of its Technology Center in Ludwigsburg. The filtration experts have integrated a fine dust particle filter and blowers in a column which also functions as a poster pillar. The blowers suck in ambient air and the filter retains particulates from the air. The filter performance can be controlled to match the level of air pollution in order to minimize the amount of energy which is required.

At bus stops or railways stations the particle filter can be integrated in advertising panels or information walls.

Brake Dust Particle Filter

Wear abrasion of the brake disks and pads in the braking process generates dust. And this is a significantly higher volume of dust than that generated by exhaust gases. Up to now the greater part of these dust particles have entered the ambient air and have contributed towards the bad quality of air in many cities. Fine particles constitute more than 90% of the brake dust and these fine particles can penetrate deep into human lungs.

The MANN+HUMMEL brake dust particle filter considerably reduces the release of particles to the air directly at the source. It retains 80% of the brake dust. The filtration experts have confirmed this in laboratory tests. They are now testing the performance of the filter under real driving conditions in test drives with Fine Dust Eater vehicles in greater Stuttgart. The filter can find application in motor cars, commercial vehicles, railway applications and industry with all types of power trains including electric, hybrid, gasoline and diesel vehicles.

NO2 Fine Dust Combi Filter

In presence of heavy air pollution in cities, significant amounts of particles and harmful gases could possibly enter the interior of vehicles leading to high concentrations of pollutants inside the vehicles. The NO2 fine dust combi filter from MANN+HUMMEL protects the vehicle occupants against the risks to health posed by air pollution.

A particle filter layer coated with ultra-fine nanofibers enables improved protection against fine particulates. The use of different layers of activated carbon enables the filter to offer improved protection against numerous harmful gases such as toxic nitrogen oxides. Due to special coating of the filter also ammonia can be reduced on a higher level, while a biofunctional layer binds allergens and prevents the growth of bacteria. As a result unpleasant odors are reduced.

The NO2 fine dust combi filter is installed in the Fine Dust Eater vehicles. In general, it is suitable for use with all passenger cars, commercial vehicles, the railway sector and industrial applications.

The Current Status of the Project

MANN+HUMMEL tested the different filtration applications during the winter months under conditions with high levels of air pollution and weather conditions with slush, snow, ice and dirt.

The use of additional vehicles and sensors has made the test drives even more effective and reliable.  According to the test results to date, the filters meet the self-imposed targets and the findings from the simulations. The closer the filters are to the fine dust source, the more effective the systems are.

With the use of filter columns in Ludwigsburg, MANN+HUMMEL has added stationary filtration of particulates to the existing mobile applications. This technology was met with immediate interest: Beginning October 2018, MANN+HUMMEL will equip the Stuttgart Neckartor with stationary filtration systems. The project aims to reduce the number of days that particulate matter limits are exceeded.

MANN+HUMMEL is holding talks with interested parties from the public and private sectors on all filtration technologies. This does not only apply to Germany, as in other parts of the world, urban air pollution can be substantially higher. MANN+HUMMEL is using its global network and has expanded its Fine Fust Eater project to China, India, and Korea.

Contact Persons

Thomas Michalak
Sales & Business Development Manager - Fine Dust Eater