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Study quantifies the burden of disease attributable to nitrogen dioxide

Scientists at the Helmholtz Zentrum München have examined exposure to nitrogen dioxide (NO2) in Germany and modeled the effects on health. The study, commissioned by the German Federal Environment Agency (UBA), is the first detailed assessment of the impact of long-term exposure to NO2 in Germany.

© Umweltbundesamt

“Our work has provided a solid foundation of data on the possible adverse health effects of the – at times – high levels of nitrogen dioxide pollution in German cities,” explained Prof. Annette Peters, Director of the Institute of Epidemiology at the Helmholtz Zentrum München (EPI). She and her team evaluated data obtained from measurements of NO2 concentrations for the period 2007 to 2014 and combined it with demographic and health statistics. Their calculations were based on the Environmental Burden of Disease concept developed by the WHO. “The findings will now allow a debate, which is rather based on scientific facts than on ideological points of view,” Peters said.

The study revealed, for example, that roughly eight percent of all cases of diabetes in Germany are linked to exposure to NO2 in outdoor air. For the year 2014, that equates to about 437,000 people affected by the disease. In their survey of asthma, the researchers estimated 439,000 sufferers (in 2012), or about 14 percent of all cases. The authors also presented concrete figures for cardiovascular diseases: statistics for 2014 indicate about 6,000 premature deaths due to high NO2 concentrations. A detailed calculation for the same year revealed around 50,000 years of life lost (YLL) in Germany.*

“Our model calculations were deliberately based on cautious assumptions,” explained Dr. Alexandra Schneider, head of the working group at the EPI and first author of the study. Only those diseases that showed strong evidence for being associated with exposure to NO2 pollution were taken into consideration. Other diseases – such as myocardial infarction, lung cancer and premature births - were not included in the analyses due to the lack of conclusive studies about their link to NO2. “Furthermore, we limited our figures to NO2 pollution levels exceeding 10 μg/m3, although to date no clear threshold value is known,” she added.

Berlin, Munich and Brandenburg used as model regions

As regards the burden of disease for the population of Germany as a whole, only background NO2 concentrations in urban and rural areas were considered, due to methodological constraints. Existing levels of air pollution on busy roads and at traffic hot spots were not included in the study.

In order also to assess the impact of air pollution in conurbations, estimations of the traffic-related share of the burden of disease attributable to NO2 were made in selected model regions: the cities of Berlin and Munich and the state of Brandenburg. The results for Brandenburg revealed a 165 percent increase in the burden of disease. The figures for Berlin and Munich were 40 – 52 percent higher than background concentrations of NO2 in the respective cities alone.

In recent years, figures have shown a certain dynamics: “On a positive note, over the past few years the numbers have fallen slightly. However, the health impacts of NO2 pollution remain significant,” Institute director Annette Peters concluded.

The study and further materials and contacts can be found on the UBA website:

Further Information

* The relationship between exposure to nitrogen dioxide and myocardial infarction has been found in several studies by scientists around the world. The authors of the current work now went one step further by calculating the effect of the average population density on the German population.

All the studies involved which quantify the link between exposure and disease, made adjustments for lifestyle factors such as obesity and smoking, i.e. they factored out their influence.

IVU Umwelt GmbH Freiburg was also involved in the study conducted on behalf of the Federal Environment Agency (UBA).

Epidemiology itself cannot provide proof of a causal relationship, because the study was no controlled experiment. However, according to the authors, epidemiology is the only way to directly quantify the effects of NO2 on the population. Moreover, there are no diagnostic possibilities to assign the death of humans directly to the irritant gas. In the future, joint work with other disciplines such as toxicology will be needed to further clarify the connection. "Until then, epidemiology remains the best tool we have to describe the effects of NO2," explains Annette Peters.

Scientists at the Institute of Epidemiology have been working for many years on the effects of air pollution on health. In 2016, for example, a team led by Dr. Kathrin Wolf showed that the risk of developing insulin resistance as a precursor to type 2 diabetes increases among people who live in areas with high levels of air pollution.

Further studies on the effects of air pollution on diabetes, allergies, respiratory and cardiovascular diseases as well as on mental health will be conducted in interdisciplinary teams.

Original Publication:
Schneider, A. et al. (2018): Quantifizierung von umweltbedingten Krankheitslasten aufgrund der Stickstoffdioxid – Exposition in Deutschland. Umweltbundesamt, March 2018

As German Research Center for Environmental Health, Helmholtz Zentrum München pursues the goal of developing personalized medical approaches for the prevention and therapy of major common diseases such as diabetes mellitus, allergies and lung diseases. To achieve this, it investigates the interaction of genetics, environmental factors and lifestyle. The Helmholtz Zentrum München has about 2,500 staff members and is headquartered in Neuherberg in the north of Munich. Helmholtz Zentrum München is a member of the Helmholtz Association, a community of 19 scientific-technical and medical-biological research centers with a total of about 37,000 staff members. 

The Institute of Epidemiology (EPI) assesses genetic, environmental and lifestyle risk factors which jointly determine the occurrence of major chronic diseases. The focus is on the development and progression of metabolic, respiratory and allergic diseases, as well as heart diseases and mental health. The goal is to understand the molecular underpinning of disease better and to translate this knowledge into personalized approaches of prevention as well as polices to improve health. Research builds on the unique resources of the KORA cohort, the KORA myocardial infarction registry, and the KORA aerosol measurement station. Aging-related phenotypes have been added to the KORA research portfolio within the frame of the Research Consortium KORA-Age. Moreover, the institute makes use of the birth cohorts GINI and LISA. It plays a leading role in the planning and setting up of the German National Cohort and builds the NAKO biorepository.