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German lung doctors admit to mistakes in study

February 15, 2019

Only 112 out of 3,800 lung doctors asked to sign a controversial study calling on Germany to rethink its air pollutant limits did so. Now, even they've admitted that they messed up some of the calculations.

Car emissions
Image: picture-alliance/chromorange/C. Ohde

More than 100 lung doctors who sparked a debate about the validity of EU limits on air pollutants have admitted their controversial study criticizing the limits included mistakes.

The former head of the German Society for Pneumology, Dieter Köhler, acknowledged the errors after the tageszeitung newspaper published an article detailing the miscalculations.

The study by Köhler and 111 other lung specialists said there was "no scientific justification for the current limits" on nitrogen oxide and particulates and called for a re-evaluation of prior studies.

Read more: Where is Europe's air safe to breathe?

Basic math

To support their claim, the doctors said that at current limits, an 80-year-old, non-smoker breathed in a similar amount of nitrogen oxide over the course of their life as a regular smoker did in the space of several months. The implication in the study was that the pollutants were not as dangerous as set out by EU limits or regular smokers would have been dying in a matter of months.

In reality, a regular smoker breathes in a comparable amount of nitrogen oxide in six to 32 years, according to corrected calculations. Authorities had also said the effects of long-term exposure to pollutants, such as air pollution, could not be compared to those of short-term exposure, such as when smoking.

Köhler admitted that the study miscalculated how much cigarettes contribute to levels of airborne particulates because he "was not aware" of existing EU cigarette regulations.

Köhler nevertheless dismissed that the mistakes undermined the study's central claim. The "magnitude" of the study's calculations were correct, he said.

Read more: Five of the world's biggest environmental problems

Who will foot the bill for Germany’s pollution problem?

Minority opinion

The study was published in January by 112 out of 3,800 lung specialists who had been asked to sign it. Many experts quickly condemned it as out of line with recent research.

There were currently "no reliable findings that would suggest a need to revise" current EU pollutant levels, the German Center for Lung Research said.

Read more: Air pollution linked to half million premature deaths in Europe

Some lawmakers who fear cities might ban diesel cars to meet current air pollutant levels had also welcomed Köhler's results.

Conservative Transport Minister Andreas Scheuer wrote a letter to the European Commission asking for a review of existing limits shortly after the study was published.

Andreas Scheuer
Transport Minister Andreas Scheuer had welcomed the results of the studyImage: Imago/snapshot

The head of the Green Party in the German parliament, Oliver Krischer, criticized Scheuer for "adopting" the results without question.

After the study's mistakes emerged on Thursday, the Transport Ministry said the authors had provided an "impetus" to the scientific debate on existing air pollutant levels.

amp/sms (AFP, dpa)

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