Use of measurements to assess the spatial representativeness areas of sampling points
Article 6
1. Both fixed and indicative measurements may be used to assess the spatial representativeness areas of sampling points, as relevant. 2. When using indicative measurements to assess the spatial representativeness area of a sampling point, Member States shall ensure that the measurements are evenly distributed over the calendar year, and over the April-to-September period for ozone, and that certain periods of the year are not over- or under-represented. When using only indicative measurements to assess the spatial representativeness area of a sampling point, Member States shall ensure that the number and spatial distribution of indicative measurements is such that the expected variability of pollutant concentrations can be reproduced to the extent possible. The uncertainty of the indicative measurement for a specific pollutant may be the uncertainty established for modelling applications in point A of Annex V to Directive (EU) 2024/2881 for the pollutant in question. 3. Member States shall identify locations with similar concentrations to the central value, as set out in Article 5(2), point (a), for a given pollutant in accordance with the methodology set out in this paragraph. A tolerance level of 15 % of the central value or a minimum tolerance level as set out in Annex I, whichever is greater, shall be applied above and below the central value to calculate a concentration interval. Values may be rounded to two significant digits when calculating the concentration interval referred to in the second subparagraph. The measured concentration of the pollutant in question at a given location shall be compared to the concentration interval calculated in accordance with the second subparagraph. When the measured concentration at a given location falls within the concentration interval calculated in accordance with the second subparagraph, that location shall be included in the area identified in accordance with Article 5(2). 4. Member States may use modelling applications in accordance with Article 7 to also include areas in the vicinity of the locations identified in accordance with paragraph 3 of this Article in the spatial representativeness area of a sampling point. Expert analysis, including but not limited to the assessment of location and source-related information in accordance with Article 5(3) and (4), may be applied to include also areas in the vicinity of the locations identified in accordance with paragraph 3 of this Article in the spatial representativeness area of a sampling point. Expert analysis may also be underpinned by measurement results from non-reference or non-equivalent measurement methods.