Article 2.5.2.2.6.

§ 1.

The location of the sampling points for ozone measurements shall be determined in accordance with the criteria stated in Appendix 2.5.3.8.

§ 2.

In zones or agglomerations where measurements are the only source of data for assessing the air quality, the number of sampling points for fixed measurements of ozone may not be less than the minimum number of sampling points stated in Appendix 2.5.3.9, Part A.

§ 3.

In zones and agglomerations where the data from sampling points for fixed measurements are supplemented by data obtained from modelling or indicative measurements, the total number of sampling points stated in Appendix 2.5.3.9, Part A may, however, be reduced if the following conditions have been met:

1° |
the additional methods provide sufficient data to assess the air quality in relation to target values, long-term objectives and information and alarm thresholds; |

2° |
the number of sampling points to be established and the spatial resolution of the other techniques are sufficient to determine the ozone concentration in accordance with the data quality targets stated in Appendix 2.5.3.1, Part A, and allow assessment results that meet the criteria stated in Appendix 2.5.3.1, Part B. |

3° |
in each zone or agglomeration there shall be at least one sampling point for every two million inhabitants, or at least one sampling point per 50,000 kmē if that criterion gives a greater number of sampling points. In each zone or agglomeration, there shall be at least one sampling point; |

4° |
nitrogen dioxide shall be measured at all remaining sampling points, except the measuring stations for determining rural background values stated in Appendix 2.5.3.8, Part A. |

The results of modelling or indicative measurements are taken into account when assessing the air quality in relation to target values.

§ 4.

Nitrogen dioxide shall be measured at a minimum of 50% of the sampling points required for ozone in accordance with Appendix 2.5.3.9, Part A. Nitrogen dioxide shall be measured continuously, except in the measuring stations for determining rural background values stated in Appendix 2.5.3.8, Part A, where other measuring methods may be used.

§ 5.

In zones and agglomerations where the concentrations in each of the last five years of measurements lie below the long-term objectives, the number of sampling points for fixed measurements is determined in accordance with Appendix 2.5.3.9, Part B.

§ 6.

At least one sampling point shall be established and used to obtain data on the concentrations of the ozone precursors stated in Appendix 2.5.3.10. The number and location of the stations where the ozone precursors are measured shall be determined taking into account the objectives and methods stated in Appendix 2.5.3.10.