Air Quality Directive
Directive 2008/50/EC on ambient air quality and cleaner air for Europe including the following elements: - The merging of most of existing legislation into a single directive (except for the Fourth Daughter Directive) with no change to existing air quality objectives - New air quality objectives for PM2.5 (fine particles) including the limit value and exposure related objectives - The possibility to discount natural sources of pollution when assessing compliance against limit values - The possibility for time extensions of three years (PM10) or up to five years (NO2, benzene) for complying with limit values.
The link address is: http://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1486474738782&uri=CELEX:02008L0050-20150918