QALY gain and health care resource impacts of air pollution control: A Markov modelling approach

This paper proposes a novel complementary approach to evaluate the public health benefits of air pollution control, where the joint impact on individuals' quality and length of life is fully quantified using Markov modelling. A Markov model which captures, for the first time: (i) air pollution's influence on population individuals' quality of life and life expectancy at baseline and (ii) dynamics in individuals' susceptibility to air pollution exposure, is developed. In order to represent the body of epidemiological evidence on the cardio-respiratory effects of long-term exposure to fine particulate air pollution, the model is structured around three diseases: chronic obstructive pulmonary disease, coronary heart disease and lung cancer. Application of the model provides the first estimates of age and gender-specific quality-adjusted life years (QALY) gains from air quality improvement in the UK. Reducing mean PM2.5 concentrations by 1 μg/m3 in London and in England and Wales is expected to yield more than 63,000 and 540,000 QALYs respectively, to adults aged 40 and above over their remaining lifetime, discounting at 3.5% p.a. At a WTP value for a QALY of £65,000, which is in line with recommendations for the UK, the expected discounted monetary benefit of the intervention amounts to £4 billion in London and £34 billion in England and Wales.