Background/aim Epidemiological studies have shown associations of nitrogen dioxide (NO₂) with numerous health outcomes. EU-wide air quality limit values for NO₂ are in place but regularly exceeded at measuring stations near roads in Germany. Therefore, a health risk assessment for the NO₂-exposure of the German population was conducted.

Methods For 2007 up to 2014, maps of the annual spatial 1*1 km² distribution of a population-weighted NO₂ concentration indicator were calculated based on assimilated modelling data of background NO₂ within a 7*8 km² grid and population density within a 250*250 m² grid. For three model regions a small scale assessment of the NO₂ exposure was achieved by considering concentrations in the higher resolved urban background as well as close to highly polluted street sections. A systematic literature search of epidemiological studies was performed to ascertain the current evidence on long-term health effects of NO₂ and to identify exposure-response-functions transferrable to Germany. The Environmental Burden of Disease-concept was applied to quantify the NO₂-associated health risks for relevant outcomes.

Results The yearly mean of background NO₂ slightly decreased from 13 μg/m³ (range: 4.3 to 37.3 μg/m³) in 2007 to 11.8 μg/m³ (3.4 to 32.7 μg/m³) in 2014. Using a counterfactual value of 10 µg/m³, 5966 (95%-confidence interval: 2031 to 9,893) premature deaths and 49,726 (16,929 to 82,456) Years of Live Lost (YLL) due to cardiovascular mortality attributable to NO₂ long-term exposure were estimated for the year 2014. Between 2007 and 2014 an overall slightly decreasing trend was observed for attributable premature deaths. The higher resolution of NO₂-concentration for the three model regions led to a substantial increase in the estimated number of premature deaths due to cardiovascular disease by 40% to 165%.

Conclusion The present estimates are based on NO₂ concentrations reflecting background exposure and thus underestimate the burden of disease. A better accuracy of the NO₂ exposure estimation accounting for the higher concentrations in urban areas close to traffic improves the burden of disease quantification and may enhance the distinction of health effects related to fine and ultrafine particles.