If, in a zone or agglomeration, the ozone concentrations have exceeded the long-term objectives stated in Appendix, Part C during one of the last five years of measurement, fixed measurements shall be carried out.


If no data are available for the last five years, or if only partial data are available, the VMM may, to answer the question of whether the long-term objectives stated in paragraph 1 were exceeded during these five years, combine the results of measurement campaigns of short duration carried out at times and locations where the levels were likely to be the highest with the data from emission inventories and modelling.