1. Institute for Health and Society, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, Tyne & Wear NE2 4AA, UK
2. Environmental Engineering Group, School of Engineering, Newcastle University, Newcastle upon Tyne, Tyne & Wear NE1 7RU, UK
3. MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London W2 1PG, UK