The Council Directive 96/62/EC of 27 September 1996 on ambient air quality assessment and management, was published on 21/11/96. This directive constitutes a milestone in the field of air quality regulations in the European Union (EU 1996). The new Framework Directive superseded the directives for SO2 and particulate matter (80/779/EEC), Pb (82/884/EEC), NO2 (85/203/EEC) and O3 (92/72/EEC) which previously were in force within the European Union.
Together with a number of daughter directives, it formed the basis for a new air quality policy within the European Union. The purpose of the Framework Directive was to set forth the basic principles of a common strategy, whilst the daughter directives established air quality standards (limit and target values and in a number of cases alert thresholds) for 13 pollutants. The common strategy in the Framework Directive was aimed, on the one hand, at assessing air quality in a common manner and informing the population thereof via established measurement methods and criteria, and, on the other hand, establishing objectives for air quality designed to avoid, prevent or reduce harmful effects on human health and the environment. In the daughter directives, these air quality objectives were defined for each pollutant in the form of limit and target values, and also a date was set by which concentration levels below the limit values are to be attained. A margin of tolerance is set leading up to the deadline when the limit value is to be met. The member states are required to implement action plans when the limit values are exceeded. The Directives also set out for each pollutant the criteria and measurement methods to be used for monitoring the air quality and the information and alert thresholds at which the population must be informed. These thresholds have been defined for substances where short-term exposure above the threshold value can pose risks to public health. Alert thresholds have been defined for NO2, SO2 and O3.