LAUSR

We thank Dr Möhner from the German Federal Institute for Occupational Safety and Health for his comments relating to our study on air pollution and risk of myocardial infarction (MI). We welcome the discussion on this important topic in particular because German governmental bodies have in the past been associated with an attitude of skepticism with regard to the hazardous effects of nitric oxides for human health. However, after critically analysing the arguments presented, we uphold our conclusion that rapid increases in nitric oxides are associated with acute MI and reject the criticism that has been raised. The argument stating that the measured values of nitric dioxide (NO2) obtained at the monitoring station in Jena cannot reflect the actual exposure of the study participants is unjustified. This is because more than 85% of the study population lived in the city of Jena, and the official Thuringian State Environmental Agency-run monitoring station providing the air pollution data is an urban background station. As such, its location was chosen to exemplify that ‘pollution levels are representative of the exposure of the general urban population’. The monitoring station situated in a residential area within the geographical centre of Jena is not subject to influences from major roads, traffic characteristics or industrial point sources. As Dr Möhner correctly states, the urban background concentration especially for NO2 reflects the prevailing concentrations even in the inner courtyard of residential buildings and is thus a realistic way to estimate individual exposure to NO2. However, to exclude any chance that the remaining 15% of our study population living close to but not directly in the city of Jena significantly biased our results, we have now performed a subgroup analysis