Article 12 Requirements where levels are lower than the limit values, target values and average exposure concentration objectives

1.   In zones where the levels of pollutants in ambient air are below the respective limit values specified in Section 1 of Annex I, Member States shall maintain the levels of those pollutants below the limit values.

2.   In zones in which the levels of pollutants in ambient air are below the respective target values specified in Sections 1 and 2 of Annex I, Member States shall take the necessary measures not entailing disproportionate costs to maintain those levels below the target values.

Member States shall endeavour to attain the long-term objectives for ozone specified in Section 2 of Annex I, and, once attained, shall endeavour to maintain the ozone levels below those long-term objectives in so far as factors including the transboundary nature of ozone pollution, volatile organic compounds from biogenic sources and meteorological conditions so permit, and provided that any necessary measures do not entail disproportionate costs.

3.   In average exposure territorial units where the average exposure indicators for PM2,5 and NO2 are below the respective value of the average exposure concentration objectives for those pollutants as laid down in Section 5 of Annex I, Member States shall maintain the levels of those pollutants below the average exposure concentration objectives.

4.   Member States shall endeavour to achieve and preserve the best ambient air quality and a high level of protection of human health and the environment, with the aim of achieving a zero-pollution objective as referred to in Article 1(1), in line with WHO recommendations, and below the assessment thresholds laid down in Annex II.