1 Introduction

The UK National Air Quality Strategy (NAQS, DoE, 1997) sets objectives for reductions in the concentrations of eight major pollutants to be achieved by the year 2005. When the objectives were set, the Government gave a commitment to undertake a formal economic analysis of the additional measures that would be required to achieve the objectives. The Department of the Environment, Transport and the Regions (DETR)-led Interdepartmental Group on Costs and Benefits (IGCB) was charged with the responsibility for fulfilling this commitment and has prepared an interim report (DETR, 1999). The purpose of the interim report, which forms part of the wider review of the NAQS, was to explain how the IGCB has conducted the economic analysis of the NAQS objectives and to present preliminary results.

Air pollution damages health and one of the major purposes of the NAQS is to ensure a high degree of protection against risks to public health from air pollution. Healthy individuals are not thought to be at significant risk from current levels of air pollution in the UK, but studies have indicated associations which persist at relatively low levels, between daily variations in levels of some pollutants and daily variations in mortality and hospital admissions for acute respiratory conditions. In some cases the mechanisms are not yet known, but the Department of Health's Committee on the Medical Effects of Air Pollutants has advised that it would be imprudent not to regard the associations as causal. An assessment of the health benefits that are likely to result from the reductions in air pollutant concentrations as a result of the implementation of existing policies is therefore an important component of an economic analysis of the NAQS. In some instances it has also been possible to assess the health benefits that could be expected to result from additional measures on top of those that are expected to result from current policies.

The health benefit calculations that are presented in the IGCB report (DETR, 1999) were undertaken at the AEA Technology National Environmental Technology Centre (NETCEN) and this report provides additional details of the methods and assumptions underlying these calculations. Details of the methods that were used to calculate the maps of estimated pollutant concentration for both current and future years that are required for the health benefit calculations are given in the following NETCEN reports: Nitrogen Dioxide (NO₂) - Stedman, Bush and King (1998), Particles (PM₁₀) - Stedman, Linehan et al (1998) and SO₂ - Abbott and Vincent (1999). The methods that have been used to map summer ozone concentrations are described in Stedman et al (1997).

Our general approach to estimating the magnitude of the health impacts of air pollutant concentrations is given in section 2. Details of the health benefits calculations that have been carried out for each pollutant for the review of the NAQS are described in subsequent sections.

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