Page 7 - Case study: Fine dust filtration in Stuttgart, Germany

1. Introduction

1.1. Background

In recent years, there is a growing awareness of the high levels of air pollution in cities. Despite air
quality in Germany improving over the years, 18 cities are still not in compliance with government-
regulated limits for certain air-borne pollutants, with most lapses due to excessively high nitrogen
dioxide (NO2) levels. NO2 is emitted from road traffic and can be dangerous in event of prolonged
exposure. In addition, particulate matter from road traffic 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. According to figures estimated by the World Health Organization, particulates
are responsible for the death of around 47,000 people every year in Germany alone, and globally,
more than 3.7 million deaths are attributed to outdoor air pollution.

In public debate, road traffic is blamed for a substantial part of both the NO2 and particulate matter
in a city. Measures such as driving bans are repeatedly discussed and are met with resistance from
the population. The non-governmental organization “Deutsche Umwelthilfe (DUH)” (The German
Environmental Aid, which champions environmental and consumer protection) filed a lawsuit
against several federal states in 2015, seeking to mandate NO2 levels and a ban on diesel vehicles.
This affected not only Stuttgart, but also other major German cities including Cologne, Düsseldorf,
Frankfurt, and Berlin. In addition, the European Union Commission has also decided to take legal
action against Germany for non-compliance, hence there is a critical need for action.

Figure 1: Size of particulate matter (PM) compared to the thickness of
human hair. PM2.5 can be lodged in the lungs, while PM10 can enter
one’s bloodstream, and considered the most dangerous.

Stuttgart, the state capital of Baden-Württemberg, adopted its first air pollution control plan in
2005. While it contained more than 30 measures leading to significant improvements in air pollution
in Stuttgart, it was not complied evenly at city-wide level. Subsequent updates of the air pollution

Fine dust filtration - Stuttgart, Germany 1