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Particulate matter (PM)

Air quality in Germany has improved over the years, also with regard to particulate matter emissions. And yet new driving bans could be imminent.

Particulate matterare tiny particles that damage the human organism. A distinction is made between fine dust particles with a diameter of 10 micrometres (= 10 millionths of a metre), 2.5 micrometres and 0.1 micrometres. Particulate matteris produced by combustion processes in motor vehicles, furnaces and heating plants. Natural particulate matter can be caused by soil erosion, but also occurs in sea spray, which carries the particulate matter with it and transports it further. Particulate mattercan also be produced by chemical reactions, e.g. the formation of ammonia in agriculture. Most particulate matter is actually released in agriculture and when bulk goods are loaded. This is followed by industry and traffic. In cities, most of the particulate matter comes from traffic. It is not only the exhaust fumes, but also the abrasion from tyres and brakes. This is why heavy electric vehicles sometimes produce more particulate matter than new diesel vehicles with very light bodies.

The smaller the dust particles, the deeper they penetrate the human body. Particulate matterwith a size of 2.5 micrometres reaches the bronchi and alveoli, ultra-fine dust with a size of 0.1 micrometres even makes it into the lung tissue and the bloodstream.

A limit value of 50 micrograms per cubic metre of air for PM10 has been set in Germany, which may be exceeded on a total of 35 days. The annual average may not exceed 40 micrograms per cubic metre of air. In Germany, this limit value has been complied with since 2019. For PM2.5, an annual average of 25 micrograms has been the limit value across Europe since 2015.

Particulate matterburden the human organs and are classified as carcinogenic. Any amount of particulate matter, no matter how small, is harmful to the respiratory tract, the cardiovascular system and the nervous system; consequently, even the limit values to be complied with do not protect the human body. Thus, attempts are being made to push the limit values ever lower. The WHO also has much stricter limits than the EU. Last year, the WHO lowered its limits for the first time in 15 years. The annual average recommendation is now no longer 10 micrograms for PM2.5 and 20 micrograms for PM10, but 5 and 15 micrograms respectively.

Low emission zones have made an important contribution to reducing particulate matter. Here, only vehicles with low emissions are allowed. The Federal Environment Agency has calculated that environmental zones lead to a reduction in emissions of five to ten percent.