Dr Heather Walton specializes in air pollution health impact assessment.  She was involved in the benefits analysis for the cost benefit analysis of the UK National Air Quality Strategy 2007, has worked on quantification of health benefits for the UK Committee on the Medical Effects of Air Pollutants (COMEAP) since 1996 and is now Chair of the COMEAP sub-group on Quantification of Air Pollution Risk (QUARK).  She was an invited expert for both the WHO projects ‘Review of the Health Aspects of Air Pollution’ and on ‘Health Risks of Air Pollution in Europe’ which set concentration-response functions for cost-benefit analysis of policies in Europe.  She has published reports on the health benefits of air pollution alert services, the health burden of air pollution in London, the air pollution and health benefits of different routes to meeting greenhouse gas emissions targets and developing methods to estimate fine scale exposure to nitrogen dioxide for the purpose of quantification across Europe.  She previously worked on air pollution in the scientific civil service, ensuring scientific evidence on air pollution and health was appropriately communicated to those developing policy.