Qualité de l’air à Koln

What is the air quality index of Koln?

Cologne or Köln in the German language is the largest city in Germany's most populous state of North Rhine-Westphalia and the fourth-most populous city in Germany. A 2019 census estimate the city’s population to be almost 1.1 million people. It is mainly centred on the left bank of the Rhine River and is 45 kilometres southeast of Dusseldorf.

At the beginning of 2021. Köln was experiencing a period of “Moderate” quality air with a US AQI reading of 55. This is according to the recommended levels by the World Health Organisation (WHO). The recorded levels of the pollutants were as follows: PM2.5 - 14 µg/m³, PM10 - 22 µg/m³, ozone (O₃) - 46 µg/m³ and nitrogen dioxide (NO₂) - 34 µg/m³.

With levels such as these, it is advisable to close doors and windows to stop the ingress of dirty air and those of a sensitive disposition should avoid venturing outside until the air quality improves.

What is the main source of air pollution in Koln?

Air pollution is increasing in Koln and road traffic and the lignite power stations on the outskirts of the city are major causes. The dangers of fine dust such as PM2.5 and PM10 have long been known. Around 310,000 people die each year in Europe as a result of this. For years, the automobile industry has been fraudulently covering up its massive excesses of limit values, including nitrogen dioxide. However, the government and authorities have not even recorded the extent of air pollution in cities across the board. So often people don't even know what health threat they are facing. In the metropolis of Koln, there are no fewer than four measuring points for fine dust but only one of them measures the particularly dangerous PM2.5 particles.

Another source of air pollutants in Koln are small combustion systems. Emissions from natural sources such as weathering, Saharan dust and emissions from agriculture play only an insignificant role in Koln. Natural sources, such as weathering, and emissions from agriculture are of no relevance for the Koln city area. Vehicle traffic has been identified as the major cause of nitrogen emissions in Koln. Locations that are particularly exposed to traffic show that nitrogen dioxide (NO₂) limits are exceeded significantly.

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

Koln has had a clean air plan for ten years now. In the case of fine dust, the requirements have now been met, as everywhere in North Rhine-Westphalia. This means that the limit of 50 micrograms is exceeded no more than 35 times a year.

An appraisal commissioned by the city came to the conclusion that in the cathedral city even a general driving ban for diesel vehicles would not be sufficient to comply with the EU limit values everywhere. That is why the city has now launched a whole package of measures; more than 50 points. Amongst other things, more electric buses are being bought and electric charging stations are being installed at convenient locations across the city. The strategy paper “Cologne Mobil 2025” aims to expand local public transport and the cycle path network.

How can people protect themselves from the dirty air in Koln?

In order to reduce the levels of nitrogen dioxide, the Koln city council have banned diesel vehicles from 4 main arterial roads. This ban is for all vehicles that do not comply with the EU standard of Euro 5/V. The situation will require constant monitoring in the beginning as there is a possibility that those banned vehicles will use adjacent roads to circumnavigate the ban and, as such, move the air pollution to another area.

Those who regularly go for walks, jog or cycle to keep fit should avoid busy roads on their training route. A London research team found that low-level physical activity near busy roads negated the beneficial effects of exercise on the respiratory tract and symptoms of cardiovascular disease. This is especially true for people who are already suffering from a heart or lung disease.

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

Air is made up of several chemical compounds. Mainly from nitrogen (N₂) and oxygen (O₂), which is essential for human survival. Carbon dioxide (CO₂) and traces of other gases are also included to a very small extent. If this natural balance is disturbed, we speak of air pollution. For the World Health Organisation (WHO), pollution always occurs when “the outside air contains substances in concentrations that are harmful to humans and their environment”. Soot, smoke, vapours, fine dust and exhaust gases are caused by heating, ovens, industry and, in urban areas, especially road traffic. Its greatest dangers are particulate matter (PM10) and nitrogen oxides (NO_x), with nitrogen dioxide (NO₂) being the most dangerous gas of all. Fine dust on the road is mainly formed by abrasion from clutches, brake pads and tyres, not by diesel engines. Its particles are tiny. The largest of these are 10 micrometres in diameter. That's 0.001 centimetres. About a tenth the diameter of a hair: invisible to the naked eye.

If fine dust particles are inhaled, this can have detrimental effects on health. The result can be irritated mucous membranes, inflammation in the windpipe and narrowed bronchi. This inflammatory condition can become chronic and thus increase the risk of heart and cerebral infarction.

Nitrogen dioxide, which is partly responsible for the rise in ozone in summer, also attacks the mucous membranes and irritates the airways. Acute too much nitrogen dioxide causes throat irritation or even shortness of breath. In the long term, it can lead to asthma, chronic bronchitis and cardiovascular disease. "Above all children whose lungs are still developing, older people whose defences are no longer so good, and asthmatics suffer from air pollution.

The effects of air pollution can be very different. A high incidence of smog also means an increased risk of absorbing fine dust. Particles with a size of 5-10 micrometres can get into the bronchi through the nasopharynx. Smaller particles with a diameter of 3 micrometres already reach the bronchioles and alveoli. Ultra-fine dust particles even penetrate into the lung tissue.

Inhalation of the harmful gases in connection with fine dust PM2.5 and PM10can cause health consequences such as cardiovascular and respiratory diseases. There is also evidence that ultra-fine dust can reach the brain via the olfactory nerve. Both intelligence and memory can be impaired, especially in children and the elderly who are exposed to high concentrations of polluted air.