1. Health Topics: Air Pollution: Ambient Air Pollutionhttps://www.who.int/health-topics/air-pollution#tab=tab_2
2. IARC Monograph: Lead and Lead Compounds,2006
3. IARC Monograph: Cadmium and Cadmium Compounds,2012
4. Directive 2008/50/EC of the European Parliament and of the Council of 21 May 2008 on ambient air quality and cleaner air for Europe;Off. J. Eur. Union,2008
5. Directive 2004/107/EC of the European Parliament and of the Council of 15 December 2004 relating to arsenic, cadmium, mercury, nickel and polycyclic aromatic hydrocarbons in ambient air;Off. J. Eur. Union,2005