The Decree aims at implementing the provisions of article 7 of Law No. 1650/86 on the protection for the environment . It also aims at harmonizing the Greek legislative frame with the provisions of Directive 2008/50/EC so as ensure that all appropriate measures are taken in order to: define objectives for ambient air quality designed to avoid, prevent or reduce harmful effects on human health and the environment as a whole; assess the ambient air quality on the basis of common methods and criteria; obtain information on ambient air quality in order to help combat air pollution and nuisance and to monitor long-term trends and improvements resulting from national measures; ensure that such information on ambient air quality is made available to the public; maintain air quality where it is good and improving it in other cases; promote increased cooperation between the Member States of the European Community in reducing air pollution. The Decree is composed as follows: objective (art. 1); definitions (ambient air, critical level, margin of tolerance, etc.) (art. 2); competent authorities (art. 3); determination of areas and agglomerations (art. 4); assessment of ambient air quality (arts. 5-11); assessment regime (art. 5); assessment criteria (arts. 6, 9); sampling points (art. 7,10); reference measurement methods (arts. 8, 11); requirements where levels are lower than the limit values (art. 12); limit values and alert thresholds for the protection of human health (art. 13); critical levels (art. 14); national PM2,5 exposure reduction target for the protection of human health (art. 15); PM2,5 limit values and alert thresholds for the protection of human health (art. 16); requirements in zones and agglomerations where ozone concentrations exceed the target values and long-term objectives (art. 17); requirements in zones and agglomerations where ozone concentrations meet the long-term objectives (art. 18); measures required in the event of information or alert thresholds being exceeded (art. 19); pollutant contributions from natural sources (art. 20); exceedances attributable to winter sanding or salting of roads (art. 21); postponement of attainment deadlines and exemption from the obligation to apply certain limit values (art. 22); air quality plans (art. 23); short-term action plans (art. 24); transboundary air pollution (art. 25); public information (art. 26); transmission of information and reporting (art. 27); sanctions (art. 28); transitional and final provisions (art. 29). Also, the sixteen Annexes included in the text constitute integral part of this Decree.