26 World Health Organisation (WHO) 118. The WHO has laid down guidelines on air quality1 to provide states with some guidance and reduce the impact on health of air pollution. The guidelines published in 1987 and updated in 1997 related to Europe. Those published in 2006 cover the entire world and are based on an assessment of current scientific data by experts. The limits on the concentration of air pollutants apply mainly to particulate matter, ozone (O3), nitrogen dioxide (NO2) and sulphur dioxide (SO2). A summary of these guidelines was published in 2006 and the complete text will be published in 2007. European standards2 The Treaty establishing the European Community 119. “Article 2: The Community shall have as its task … to promote throughout the Community … a high level of protection and improvement of the quality of the environment … 120. Article 6: Environmental protection requirements must be integrated into the definition and implementation of the Community policies and activities referred to in Article 3, in particular with a view to promoting sustainable development. 121. Article 174: 1. Community policy on the environment shall contribute to pursuit of the following objectives: – – – – preserving, protecting and improving the quality of the environment, protecting human health, prudent and rational utilisation of natural resources, promoting measures at international level to deal with regional or worldwide environmental problems. 2. Community policy on the environment shall aim at a high level of protection taking into account the diversity of situations in the various regions of the Community. It shall be based on the precautionary principle and on the principles that preventive action should be taken, that environmental damage should as a priority be rectified at source and that the polluter should pay. …” Prior assessment 122. The Community has set up a system for the assessment of the effect of public and private plans on the environment (construction work, other installations and schemes, power stations, waste treatment, deforestation, etc.), which is based on the following legal instruments: – 1 Directive 85/337/EEC, as modified by Directive 97/11/CE3, which set up a system of prior assessment of the impact of certain projects on the environment and public information; Use of the air quality guidelines in protecting public health: a global update, Fact sheet No. 313, October 2006; see WHO (European Regional Office) site: www.euro.who.int. 2 europa.eu.int/eur-lex ; europa.eu.int/scadplus 3 Official Journal L 073, 14/03/1997, p. 0005 – 0015; deadline for transposition 14 March 1999