Janke, K., Propper, C. and Henderson, J., Do current levels of air pollution kill? The impact of air pollution on population mortality in England, Health Economics Vol. 18 Issue 9, 7 April 2009, available at http://onlinelibrary.wiley.com.libezproxy.open.ac.uk/doi/10.1002/hec.1475/pdf (accessed 20 September 2012)
WHO – World Health Organisation, 2005, WHO air quality guidelines for particulate matter, ozone, nitrogen dioxide and sulfur dioxide: Global Update 2005 available at http://whqlibdoc.who.int/hq/2006/WHO_SDE_PHE_OEH_06.02_eng.pdf (accessed 20 September 2012)