1. Where, in given zones, the levels of pollutants in ambient air exceed any limit value or target value laid down in Section 1 of Annex I, Member States shall establish air quality plans for those zones that set out appropriate measures to achieve the limit value or target value concerned and to keep the exceedance period as short as possible, and in any case no longer than 4 years from the end of the calendar year in which the first exceedance was recorded. Those air quality plans shall be established as soon as possible and no later than 2 years after the calendar year during which that exceedance of any limit value or target value was recorded.
Where in a given zone an exceedance of a limit value is already covered by an air quality roadmap, Member States shall ensure that the measures set out in that roadmap are appropriate to keep the exceedance period as short as possible and, where relevant, take additional and more effective measures and follow the procedure for updating an air quality roadmap as set out in paragraph 5.