Limit values ​​for air pollution: WHO massively tighten recommendations

In new guidelines, the WHO recommends greatly reducing pollutants in the air: Even in low concentrations, they are hazardous to health. In Germany, particulate matter and nitrogen oxide levels in particular are too high.

The World Health Organization (WHO) has published new guidelines on air quality after more than 15 years. They contain recommendations for new guide values ​​for various pollutants. Above all, the pollution with fine dust and nitrogen dioxide (NO2) would have to be reduced significantly.

The value now recommended by the WHO for nitrogen dioxide is ten micrograms per cubic meter of air. In the old guidelines from 2005 it was 40 micrograms. This is how high the legally binding limit prescribed by the EU has been so far.

Recommendations for particulate matter also tightened

In the case of fine dust, according to the WHO, the long-term exposure to small particles (PM2.5) should be a maximum of five instead of the previous ten micrograms per cubic meter of air. For the somewhat larger particles (PM10), she now recommends 15 instead of the previous 20 micrograms. Here, too, the current EU limit values ​​are significantly higher: namely 25 micrograms for PM2.5 and 40 micrograms for PM10.

Fine dust is the term used for particles with an aerodynamic diameter of less than ten micrometers (µm) (PM10). Particularly small particles with an aerodynamic diameter of less than 2.5 µm (⁠PM2.5) pose an increased risk because they can penetrate deeper into the airways.

Legislators have the final say

The WHO guidelines also contain air quality values ​​for other pollutants – ozone, sulfur dioxide and carbon monoxide. However, the guidelines are only recommendations. Legally binding limit values ​​must be set by the legislator. The EU wants to discuss possible changes to the previous regulations by autumn 2022. As early as March of this year, the EU Parliament demanded that the responsible EU Commission should orient itself to the new WHO guideline values.

“The new WHO Air Quality Guidelines are an evidence-based and practical tool for improving the quality of the air on which all life depends,” said WHO Director General Tedros Adhanom Ghebreyesus. He urged all countries “to use it to reduce suffering and save lives”.

Environmental aid demands consequences

The German Environmental Aid (DUH), which has been fighting for stricter limit values ​​for years, is now calling on the federal government to act. To protect people and the environment, they should quickly lower the national limit values ​​for fine dust and nitrogen dioxide and not wait for EU legislation, said DUH managing director Jürgen Resch NDR. The government’s previous measures are “inadequate”. In the transport sector, Federal Minister Andreas Scheuer “systematically torpedoed all effective measures”. And in the Ministry of Economics, too, there has been a blockade so far, said Resch.

Resch sees the politically most explosive tightening of nitrogen dioxide. The new guideline values ​​of the WHO would mean: “We have to make nitrogen dioxide disappear from the air we breathe as much as possible.” Among other things, a speed limit on motorways and 80 km / h outside of town is necessary for this, according to Resch. In addition, motorized individual traffic in the cities must be reduced quickly and significantly. In addition, one now has to “deal with refineries, industrial plants and animal husbandry in a completely different way,” said Resch.

Greens demand quick implementation

The Greens are also calling for more extensive measures. “We have to take the new findings of the World Health Organization on the harmful effects of air pollutants seriously,” said the spokeswoman for environmental policy and environmental health of the Greens, Bettina Hoffmann, the NDR. The new guidelines would have to be implemented consistently. “There is an urgent need for action in Germany,” said Hoffmann. Because air pollution continues to be the number one environmental health risk. She calls for more bike paths to be built instead of highways, for the coal phase-out to be preferred and for cars with electric drives to be used instead of diesel engines.

In Germany, values ​​are often based on recommendations

In Germany, nitrogen dioxide levels have steadily decreased in recent years. However, in many places they are still above the current WHO recommendations. In 2020, the new guideline value of ten micrograms per cubic meter of air for nitrogen dioxide was exceeded at more than 80 percent of all measuring stations, especially on roads. The annual mean value was higher at all traffic-related measuring points in cities across Germany. According to the Federal Environment Agency (UBA), diesel vehicles are the main source of nitrogen dioxide.

The UBA has now announced that it welcomes the fact that the WHO has updated its air quality guidelines. The office will now examine in detail what the results mean for air pollution control in Germany. The guideline values ​​are “challenging” against the background of the current emissions, says Wolfgang Straff from the Federal Environment Agency. From a technical point of view, however, they are to be welcomed because of their high health relevance. In addition, most measures to reduce air pollution would also have an effect on reducing greenhouse gases, i.e. they would help to protect the climate.

WHO estimates millions of deaths

The recommendations of the World Health Organization are based on thousands of scientific studies on the health effects of pollutants. Air pollution is one of the greatest threats to human health globally. The WHO estimates that it causes seven million premature deaths worldwide every year and that it also makes many more people sick.

In children, for example, the pollutants can impair lung growth and lead to diseases of the respiratory tract, such as asthma. Heart disease and strokes are common in adults. The European Environment Agency estimates that there are around 417,000 premature deaths each year in Europe. In Germany there are therefore more than 70,000.

Scientists welcome WHO recommendations

In their initial reactions, many scientists said they were positive about the new WHO guidelines. “I see the great importance of these new WHO guidelines primarily in the fact that they show that there is no such thing as ‘harmless’ air pollution,” said Barbara Hoffmann, Professor and Head of the Environmental Epidemiology Working Group at the University of Düsseldorf at the Science Media Center (SMC) . A little air pollution is also bad for the body if it is inhaled every day, year after year. “From this it can be deduced that air pollution must be reduced everywhere,” says Hoffmann.

Annette Peters from the German Research Center for Health and the Environment in Munich said the WHO guidelines set ambitious goals and show which steps to lower them could be useful. She sees a particular need for action with fine dust. Here, the limit values ​​in the EU are far too high so far.

Limit values ​​exceeded even in the Corona year

The requirements of the EU legislation for small particles (PM2.5) of 25 micrograms per cubic meter of air were met by all measuring stations in Germany in 2020. However, the values ​​of almost all measuring stations, with only one exception, were above the new WHO recommendation of five micrograms per cubic meter of air as an annual mean – and that in the Corona year 2020, in which significantly fewer cars were in the meantime. Even with the larger fine dust particles (PM10), the annual mean at many measuring stations was over 15 micrograms, which the WHO now recommends.

Hartmut Herrmann from the Leibniz Institute for Tropospheric Research in Leipzig rates the WHO guidelines as “a long-awaited and surprisingly large and important step in the right direction”. He did not expect such strong reductions in the guideline values ​​and was pleasantly surprised. “This new generation of guide values ​​sets the bar significantly higher and will require further, substantial measures to further improve air quality,” said Herrmann.