The German view: Effects of nitrogen dioxide on human health - derivation of health-related short-term and long-term values

Two short-term limit values have been proposed to protect public health: a 1-h value of 100 μg/m3 and a 24-h mean value of 50 μg/m3. Due to the limitations of epidemiological studies to disentangle effects of single pollutants, a long-term limit value cannot be easily derived. However, applying the precautionary principle, it is desirable to adopt an annual mean of 20 μg NO2/m3 as a long-term mean standard to protect public health.