Bodennahes Ozon: Trends in Bayern

Long-term ground-based measurements of ozone in Bavaria (Germany) are evaluated in respect of their trend during the last 20 years. First a method is described to characterize the measuring-sites in relation to the levels of precursors: The derived division in three classes proved its worth interpreting the results. Following, the trend of ozone-concentration are calculated by linear regression analysis and are tested in respect of their significance. Generally the Bavarian results fit in the trends of a long-term increase of ozone-concentrations observed at several central European stations. In detail, there are differences between stations situated at elevated sites or at other sites without traffic (class I) and stations situated at sites with significant influence of nearby traffic (classes II and III). At stations of class I an increase of ozone until the mid 80’s is recorded. Afterwards this trend seems to be stopped. But at the stations of classes II and III an increase of ozone is occuring only since the mid 80’s. The observed trends are correlated with the trends of NO_x-emissions.