Air pollution control in Stuttgart

All EU member states must comply with statutory limits for particulate matter (PM10) and nitrogen dioxide (NO2). These air pollutants can cause damage to the health of the population, especially in conurbations. But they are also harmful to the climate. The main cause of these limit value violations for particulate matter and nitrogen dioxide in large cities is road traffic. For all areas and conurbations where the limit value is exceeded, the EU member state concerned must implement plans or measures to curb air pollution and comply with the limit value.

For this reason, the state of Baden-Württemberg adopted the first clean air plan for the state capital of Stuttgart in 2005. This air pollution control plan already included more than 30 measures that led to a significant improvement in air pollution levels in Stuttgart, but not yet to city-wide compliance with the limit values. For this reason, the Regional Council introduced additional measures with the 1st and 2nd updates of the Clean Air Plan in 2010 and 2014.

Nevertheless, it was not possible to comply with the limit values for short-term pollution for particulate matter and the limit value for long-term and short-term pollution for nitrogen dioxide everywhere in the Stuttgart urban area. For this reason, the Clean Air Plan has been updated in several versions in recent years and additional measures have been introduced. Since 2005, the measures of the air pollution control plan have included the introduction of the environmental zone, a ban on trucks passing through, and the stabilization of traffic.

The state capital is concerned to improve the quality of life in Stuttgart additionally with  urban measures for air pollution control. One basis for this is the  action plan "Sustainably mobile in Stuttgart" of July 18, 2017, which was presented by the Lord Mayor and adopted by the City Council.

Today, there is a broad bundle of urban measures that interlock to keep the air clean: These include investments in public transport, walking and cycling, measures to liquefy traffic, more urban greenery for the urban climate, projects such as the air filter columns or street cleaning. The measures taken by the city of Stuttgart also included the  fine dust alert from 2016 to 2020, which is unique in Germany. The aim of the fine dust alert was to reduce the expected pollution with air pollutants such as fine dust during weather conditions in Stuttgart with a high degree  of low exchange.

Thanks to these many activities by the state of Baden-Württemberg and the state capital, the pollution caused by particulate matter and nitrogen dioxide in Stuttgart has decreased in recent years. In 2018 and 2019, the legal particulate matter limits were met at all measuring stations in the city area. In contrast to particulate matter, the values for nitrogen dioxide are still above the limi of low exchange.

Thanks to these many activities by the state of Baden-Württemberg and the state capital, the pollution caused by particulate matter and nitrogen dioxide in Stuttgart has decreased in recent years. In 2018 and 2019, the legal particulate matter limits were met at all measuring stations in the city area. In contrast to particulate matter, the values for nitrogen dioxide are still above the limit value. Here, too, there have already been significant improvements, but they do not yet meet the legal requirements.

The German Environmental Aid Association (DUH) therefore filed a lawsuit against several German states in 2015. DUH wants to oblige the federal states to amend their clean air plans so that the limit value for nitrogen dioxide is complied with. It is therefore calling for a driving ban on diesel vehicles. In addition to Stuttgart, the cities of Cologne, Düsseldorf, Frankfurt and Berlin are also affected.

The Stuttgart Administrative Court upheld DUH's complaint on July 28, 2017. In October 2017, the state government filed an appeal (Sprungrevision) against the ruling of the Administrative Court. The Federal Administrative Court rejected the jump appeal on February 27, 2018. Accordingly, the court considers diesel driving bans in cities - subject to proportionality - to be permissible in principle.

In order to comply with the nitrogen dioxide limits in the Stuttgart environmental zone as quickly as possible, the state of Baden-Württemberg had to introduce diesel traffic bans for certain diesel vehicles due to the court rulings. The city of Stuttgart must comply with this order and implement the regulations:

• On January 1, 2019, the state of Baden-Württemberg introduced a zonal traffic ban for all motor vehicles with diesel engines of emission standard Euro 4/IV and worse. The traffic ban applies all year round in the environmental zone of the city of Stuttgart. The zonal diesel traffic ban has affected residents of Stuttgart since April 1, 2019.
• Since January 1, 2020, there has been a route-based traffic ban in the Stuttgart city area for all diesel cars of the Euro 5/V emission standard and worse. Preparations are currently underway to implement zonal traffic bans for diesel vehicles of emission class 5/V in the districts of Stadtmitte, Bad Cannstatt, Feuerbach and Zuffenhausen. This has also been decided by the state of Baden-Württemberg.

The diesel traffic bans are set out in the respective updated clean air plans. They are based on rulings by the Stuttgart Administrative Court and the Federal Administrative Court.