Estimating the health burden of air pollution to support Local Air Quality Management in Wales

PhD researcher

Huw Brunt

Director of Studies
Professor Enda Hayes

Introduction

Exposure to air pollutants such as PM₁₀ and NO2 has been associated with an risk of respiratory and cardiovascular disease-related morbidity and mortality. Spatial and temporal variations in ambient air pollution levels mean that exposures and associated health risks can vary across different communities and population groups (which may indicate the presence of inequalities). Additionally, since health is a function of a person’s socio-economic and environmental circumstances, as well as hereditary and personal influences, health impacts from exposures are also likley to vary across and within population groups, according to susceptibility. Although the relationships between air pollution, health and social factors are extremely complex, it is important to understand and quantify them so that effective action can be targeted to reduce air pollution levels, risks and impacts.

The UK Local Air Quality Management (LAQM) regime, a product of the Environment Act 1995, facilitates the co-ordination and prioritisation of such action. This framework requires Local Authorities to cary out periodic and systematic assessment of air quality, identify air pollution ‘hotspots’ where people may be exposed, and take measures (through declaring Air Quality Management Areas with accompanying action plans) to protect population health. Whilst led by Local Authorities (usually Environmental Health Departments), the LAQM framework calls for intra and inter-agency collaboration to maximise synergies and coordinate efforts to work in pursuance of national health-based Air Quality Objectives (AQOs) for key pollutants. Given that, essentially, LAQM is a tool to facilitate air quality and public health risk assessment and intervention, it is of no surprise that health authorities have been identified as having a key role to play in the delivery of effective LAQM action. This is especially relevant given: the wealth of contemporary evidence linking air pollution exposure with adverse health effects, the primary objective of the original UK National Air Quality Strategy being “to make sure everyone can enjoy a level of ambient air quality in public places which poses no significant risk to health or quality of life”, and the aim of action taken to address air pollution at the local level being to reduce population exposures, risks, health effects and, consequently, demand on health services.

Whilst a comprehensive understanding of local air quality has been developed over many years, it remains the case that little is known about the local-level health burden associated with spatial and temporal variations in air pollution. It is possible that this knowledge has hindered the delivery of evidence-based, appropriately targeted population health-focused LAQM action so far i.e. action informed by both local air pollution and health profiles. To date, most research in this area has investigated the effects-based impacts of LAQM action on ambient air pollutant concentrations (as a proxy measure for population health impact). In addition to facilitating the LAQM process, the availability of this information may also help "health" agencies to respond positively to criticism that that they should play a greater role in, and contribute more to, the LAQM process.

Research aims

This research aims to estimate local air pollution-related health impacts in Wales by drawing upon existing air quality (PM₁₀ and NO2), health outcome (cardiovascular and respiratory hospital admissions and mortality, and all cause mortality) and socio-economic status (Welsh Index of Multiple Deprivation) data and consider these impacts in the context of LAQM action. It is intended that these local health burden estimates will:

1. help target future action (considered in the context of local broader public health issues)
2. facilitate collaboration
3. act as baseline measures to help evaluate intervention (health) impact and effectiveness.

A critique of the implementation of the LAQM regime in Wales will attempt to identify ways in which such local-level air pollution and health burden estimates can be used to add value to the current LAQM process and facilitate a greater degree of collaboration between Local Authorities and public health specialists, and others.

To achieve this, the following research objectives are proposed:

1. Estimate the local-level health burden associated with spatial and temporal variations in ambient air pollution (PM₁₀ and NO2) in Wales.
2. Apply these estimates to determine the impact that LAQM action taken in Wales has had on protecting public health.
3. Critically evaluate the LAQM regime, as implemented in Wales, to identify ways in which local air pollution-related health burden estimates could be used to add value to the process and increase collaboration between Local Authorities and health agencies.
4. Assess the need to advocate for changes to Local Air Quality Management and health and wellbeing policy.