1. World Health Organisation , WHO Air Quality Guidelines for Particulate Matter, Ozone, Nitrogen Dioxide and Sulfur Dioxide, Global update 2005 edn, WHO Press, Geneva, 2006
2. National Society for Clean Air and Environmental Protection , NSCA Pollution Handbook 2007, National Society for Clean Air and Environmental Protection, Brighton, 2007
3. Department for Environment Food and Rural Affairs , The Air Quality Strategy for England, Scotland, Wales and Northern Ireland, TSO (The Stationery Office), Norwich, 2007
4. Personal Monitoring Device for Gaseous Contaminants
5. Personal sampler for nitrogen dioxide