Air quality in Stuttgart

What is the air quality index of Stuttgart?

Stuttgart is the largest city in the German state of Baden-Württemberg and also is regarded as its capital. It is located in the fertile Neckar River valley and is about one hour’s drive away from the Black Forest. At the end of 2019, it had an estimated metropolitan population of 5.3 million people. This makes it the sixth-largest city in Germany.

At the beginning of 2021, Stuttgart was experiencing a period of “Moderate” quality air with a US AQI reading of 68. This figure is based on guidelines by the World Health Organisation (WHO). The concentration levels of the pollutants were as follows: PM2.5 - 20 µg/m³, PM10 - 28 µg/m³, ozone (O₃) - 4 µg/m³ and nitrogen dioxide (NO₂) - 18.5 µg/m³. With levels such as these, it would be advisable to keep doors and windows closed so as to prevent the ingress of polluted air and those of a sensitive disposition should avoid outdoor activities until the air quality improves.

What is the main source of air pollution in Stuttgart?

Air pollution control is a big issue in Stuttgart. Lots of industry, lots of traffic, little wind and the basin location lead to increased air pollutants such as fine dust and nitrogen dioxide. So the city is taking a lot of measures to contain pollution and make the air cleaner.

According to the measurements, around 85 per cent of the traffic-related fine dust with a particle size of PM10 (up to ten micrometres in diameter) is caused by tyre, brake and road abrasion and by the swirling up of the dust layer on the roadways.

What is the air pollution level in Stuttgart?

In 2018 and 2019, the statutory fine dust limit values were observed at all measuring stations in the city. In contrast to fine dust, the values for nitrogen dioxide were still above the limit value. Here, too, there were already significant improvements, but they do not yet meet the legal requirements. At one city centre measuring point where the highest dust concentrations have been measured: per cubic meter of air, only 1.9 micrograms of fine dust were found to be coming from the exhaust pipes of passing cars. 11.9 micrograms, on the other hand, were caused by abrasion and turbulence. In other words, even if only emission-free electric cars drive through the city, hardly anything will changed in the fine dust pollution of the air. Abrasion from brakes, tyres and resurgence is just as common in electric cars as in cars with internal combustion engines.

Is air pollution in Stuttgart getting better or worse?

Looking at the air quality over the past few years, it can be seen to be slowly improving. In 2017 the average annual figure for the concentration level of PM2.5 was 13.6 µg/m³. In 2018, it was 12.8 µg/m³ and in 2019 it was 11.7 µg/m³. For the months of May, June and August, Stuttgart attained the target figure set by the WHO as being less than 10 µg/m³. March and June recorded “Good” levels with figures between 10 and 12 µg/m³.

January, February and April deteriorated slightly to “Moderate” levels with figures between 12.1 and 35.4 µg/m³. Unfortunately, the figures are missing for the remaining months.

The air in numerous German cities got significantly better in 2019, at least in terms of nitrogen oxide (NO) pollution. According to a media report, this is based on figures from the Federal Environment Agency.

According to a newspaper report, the number of German cities that exceed the nitrogen oxide limit had fallen by more than half in 2019. 25 cities had exceeded the limit of 40 micrograms of nitrogen oxide (NO₂) per cubic meter of air as an annual average, as quoted in the press from an evaluation of the measurement data from more than 500 measuring stations in the federal states.

In 2018, older diesel-powered vehicles were prohibited from entering the city centre. All vehicles must meet the current emission standard Euro 6. The planned driving ban is part of a package of measures to improve air quality in Stuttgart. In addition, local public transport, as well as bicycle and foot traffic, are to be improved and speed limits are to be imposed, according to a government announcement.

What can be done to improve the air quality in Stuttgart?

All EU members have to observe statutory limit values for fine dust (PM10) and nitrogen dioxide (NO₂). These air pollutants are detrimental to the health of the population, especially in metropolitan areas. But they are also harmful to the climate. The main cause of these limit values being exceeded for fine dust and nitrogen dioxide is road traffic in large cities.

A “Clean Air Plan” was introduced as far back as in 2005 with two subsequent updates. A further update was introduced in 2018 which included investments in local public transport, walking and cycling zones, measures to liquefy traffic, more urban greenery for the urban climate, projects such as air filter columns and street cleaning.

On 1^st January 2019, the state of Baden‐Württemberg introduced a zonal traffic ban for all vehicles with diesel engines that comply with the Euro 4 / IV emissions standard and lower. This was modified the following year to ban all diesel cars with the Euro 5 / V emissions standard and worse.

What are the effects of breathing Stuttgart’s poor quality air?

Air pollution is a ubiquitous issue, especially in large cities, as increased traffic is a particular cause of air pollution. The pollutants that are released into the air have devastating consequences for the environment and our health and are mainly due to human activities.

Dry clean air consists of 78 per cent nitrogen, around 21 per cent oxygen and approximately 1 per cent argon as well as other trace gases such as carbon dioxide and methane. In addition, natural and man-made gases and particles are added to it, which cause the actual air pollution.

Air pollutants should normally not be in our atmosphere at all or only in small quantities. They can have harmful effects on human health as well as the environment and the climate.

Commonly found air pollutants are: carbon monoxide, fine dust (PM2.5 and PM10), ammonia, sulphur dioxide, nitrogen oxides and ozone.