http://www.euro.who.int/en/health-topics/environment-and-health/pages/european-environment-and-health-process-ehp/environment-and-health-in-europe-status-and-perspectives
http://www.euro.who.int/en/health-topics/environment-and-health/air-quality/publications/2017/evolution-of-who-air-quality-guidelines-past,-present-and-future-2017
https://www.eea.europa.eu/help/glossary
http://www.euro.who.int/__data/assets/pdf_file/0006/189051/Health-effects-of-particulate-matter-final-Eng.pdf
http://radontestingdallas.com/indoor-air-quality-testing-composition-dust-particles-particulate-matter/
http://acmg.seas.harvard.edu/people/faculty/djj/book/
https://www.eea.europa.eu/publications/air-quality-in-europe-2017
http://ec.europa.eu/eurostat/statistics-explained/index.php/Energy_production_and_imports
