Page 8 - Case study: Fine dust filtration in Stuttgart, Germany

control plan were made in 2010 and 2014. Despite additional measures, short-term exposure to
particulate matter (see fig.1) and short- and long-term exposure to NO2 often remain exceeding
their limit values in Stuttgart. A road section at Neckartor has been particularly affected by rising
levels of pollutants in recent years.

1.2. Challenge and response

The Stuttgart “fine dust alarm”, unique to Germany, has significantly raised public awareness on the
issue of air pollution. An alarm is triggered as soon as the German Weather Service forecasts that
the atmosphere will have a severely limited ability to disperse particulate matter and NO2 on at
least two consecutive days, indicating a risk that the limit might be exceeded. Car travel should be
avoided, and the use of fireplaces, prohibited.

The local pollution is mainly due low wind conditions and pollution from power generation and
agriculture around the region; as well as urban pollution caused by building sites, households, and
small consumers. Furthermore, concentrated road traffic in Neckartor combined with poor air
circulation added to the problem.

Despite various regulatory and behavioral measures taken by the city and its populace, long term,
lasting change was still elusive. The key challenge was to clean up the air in Neckartor, for good.

Response, through innovative technologies

The work started off by asking, “What if we could improve the air quality along the road?”.

At MANN+HUMMEL, a filtration technology for particulate matter reduction was being developed.
The impact of the technology was simulated based on current pollution levels and subsequently.
With the support of the city of Stuttgart and the Ministry of Transport for Baden- Württemberg, the
technology was piloted at a critical street junction at Neckartor. The technology was designed into
modular cubes, code-named “Filter Cubes”. A further development of this filtration technology was
to use the Filter Cubes to reduce NO2 on site as well, solving the two major issues raised above.

2. The smart project

2.1. Vision and content

Relation to city-wide vision and strategy

The city of Stuttgart is taking various measures to improve air quality in polluted areas and in the
city as a whole in order to achieve their green vision. The pilot project from MANN+HUMMEL,
sponsored by the Ministry of Transport in Baden-Württemberg and supported by Stuttgart, was
implemented at the Neckartor road junction in Stuttgart at the end of 2018.

2 Fine dust filtration - Stuttgart, Germany