1. AQUILA network on Air Quality National Reference Laboratories (http://ies.jrc.ec.europa.eu/aquila-homepage.html).
2. EU Thematic Strategy on Air Pollution (http://ec.europa.eu/environment/air/quality/index.htm).
3. European Environment Agency (EEA) Database on Air Pollution in Europe (http://www.eea.europa.eu/data-and-maps/data/airbase-the- european-air-quality-database-7#tab-european-data).
4. EU Air Quality Directive 2008/50/EC (http://ec.europa.eu/environment/air/quality/legislation/existing_leg.htm).
5. COST Action TD1105 EuNetAir webpages: www.cost.eunetair.it.