1. 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.
2. 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.
3. The average exposure indicator for PM_{2,5} shall be assessed in accordance with Section A of Annex XIV.
4. 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.