Member States shall take all necessary measures not entailing disproportionate costs to reduce exposure to PM_2,5 with a view to attaining the national exposure reduction target laid down in Section B of Annex XIV by the year specified therein.

Member States shall ensure that the average exposure indicator for the year 2015 established in accordance with Section A of Annex XIV does not exceed the exposure concentration obligation laid down in Section C of that Annex.

The average exposure indicator for PM_2,5 shall be assessed in accordance with Section A of Annex XIV.

Each Member State shall, in accordance with Annex III, ensure that the distribution and the number of sampling points on which the average exposure indicator for PM_2,5 is based reflect the general population exposure adequately. The number of sampling points shall be no less than that determined by application of Section B of Annex V.