1. WHO. Air quality: Date and statistics [citado 23 May 2017]. Disponible en: http://www.euro.who.int/en/health-topics/environment-and-health/air-quality/data-and-statistics
2. WHO. Air quality guidelines for particulate matter, ozone, nitrogen dioxide and sulfur dioxide: Global update 2005. Genebra 2005.
3. International Agency for Research on Cancer. Outdoor air pollution a leading environmental cause of cancer deaths. Press Release n.o 221. 2013;2-5.
4. ENHIS. Database: outdoor air pollution in cities [citado 23 May 2017]. Disponible en: http://www.who.int/phe/health_topics/outdoorair/databases/en
5. Health Effects Institute. Annual report, 2016.