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Traffic Emits the Tiniest of Particles

A new Hereon study shows: The air in Hamburg reveals very high concentrations of ultrafine particles at some places

Researchers at the Helmholtz-Zentrum Hereon have taken air measurements in the last year at various traffic-related locations in Hamburg and modeled this data for the entire city. The finding is that the pollution from ultrafine particles (UFP), which can have negative effects for health, is very high at selected places. Close to ferry terminals, concentrations as high as at busy roads were measured. The results of the study have been published in the scientific journal Toxics and can be transferred to other port cities.

Taking a ferry in Hamburg has cult status. Locals enjoy slowing down this way. Tourists use ferries as an affordable alternative to the big harbor tour. However, Hereon researchers from the Institute of Coastal Environmental Chemistry have discovered that taking ferries could be harmful to one’s health. “The risk still needs to be studied in more detail, but it is well known that ultrafine particles have negative health effects. This is why we first investigated the distribution of these particles in Hamburg,” says Dr. Matthias Karl, a geoecologist and application developer who led the study. The publication in Toxics is attracting attention beyond the borders of Hamburg.

Methodical Prowling

Ferryboat in Hamburg

Hamburg ferries are also responsible for elevated levels of ultrafine particles in the air. Photo: Hereon/ Matthias Karl

It is already a familiar problem known from docks for cruise ships or from giant container ships: pollution stemming from ultrafine particles that arise and are released from the operation of diesel engines. The air is also polluted with UFPs by street traffic, from air traffic and from heating using oil or wood in winter. The Hereon scientists first took air measurements at important traffic junctions in Hamburg. “For this purpose, you need the right location where the air particles can be measured well. In the meantime, we have gained essential insights into the distribution of air pollutants in Hamburg through model studies that had already been carried out, “says Dr. Martin Ramacher, head of a junior research group at the Hereon Institute of Coastal Environmental Chemistry.

The researchers took the measurements during five days, beginning in February 2021 at the following locations: at Max Brauer Allee, at Sternschanze, in Neugraben and at the ferry terminal area in Övelgönne. The technical equipment used was the P-TRAK mobile device, a particle counter for ultrafine particles. The ultrafine particles are smaller than one hundred nanometers, or simply put: one thousandth the diameter of a human hair. The device begins measuring from seven nanometers in size. The real-time measurements were then enhanced through modeling to create a more comprehensive picture from the point measurements. Because air pollution also very much depends on the weather, results were based on weather models created by the German Weather Service for Hamburg. “The weather is a decisive factor. For example, it is often windy in Hamburg and the UFPs can be carried out of the city more quickly,” says Marvin Lauenburg, who prepared, implemented and evaluated the measurement campaign.

The research results are, however, clear: the concentration level of these small particles in Hamburg is high. The measurements show concentrations in the range of 15,000 to 30,000 particles per cubic centimeter near the ferry terminals and at the locations with street traffic. The urban background concentrations are usually 4,000 to 12,000 particles per cubic centimeter, while the regional background concentrations are in the range of a few 1000 particles per cubic centimeter. This means that the concentrations of ultrafine particles near the ferry terminal and near streets in central Hamburg are five to ten times greater than concentrations in the regional surroundings of Hamburg. Unlike for particulate matter, for example, there is no fixed limit value yet for UFP number concentrations. This is mainly due to the limited availability of necessary information on UFP pollution.

Future Prognosis

“I have never been involved in a study that moved so quickly from field research to publishing results,” says Matthias Karl. In addition, the results can easily be transferred to other port cities. The more robust the weather data, the closer the modeled UFP concentrations are to measurements.

The health hazards of ultrafine particles are yet to be precisely studied. Numerous studies and also the Umweltbundesamt indicate possible health effects by these tiny particles, which can reach deep into the lungs and can even be taken up into the bloodstream. Clearly, more research is needed. In the future, Hereon researchers want to create similar models for the Frankfurt Airport in the Rhein/Main region and for the capital city of Berlin. In cooperation with researchers at the Universitätsklinikum Hamburg-Eppendorf (UKE), the associated health risks for Hamburg and Berlin will also be examined in more detail.

Overall, the following applies to all sources of ultrafine particles, such as street traffic, aircraft or ships: only very good exhaust gas purification systems and alternative, combustion-free engines are capable of reducing the danger to human health. This is the only way residents and travelers can breathe safely.

Further Information


Dr. Matthias Karl Scientist

Phone: +49 (0) 4152 87-2368

E-mail contact

Institute of Coastal Environmental Chemistry
Helmholtz-Zentrum Hereon

Christoph Wöhrle Press Officer

Phone: +49 (0) 4152 87-1648

E-mail contact

Communication and Media
Helmholtz-Zentrum Hereon