The effect of air pollution on health and mortality

Background

Ambient air pollution is the biggest environmental threat to public health in the UK. Research suggests that the breathing of polluted air is associated with the development and exacerbation of various health conditions, and the cost of treating such conditions is substantial.

 

Aims & Key Questions

This project investigates the effects of air pollution on mortality and a range of morbidity outcomes, as well as birth outcomes. The project links pollution data to various individual-level datasets for Northern Ireland (NI), including multiple years of census data, prescriptions records and birth records, and focuses on the effects of fine particulate matter pollution (PM_2.5), considered to be the most harmful pollutant for human health. It first estimates the impact of long-term exposure on various self-reported health outcomes among adults, and then investigates the link with mortality. Focussing on children, it assesses air pollution effects on childhood asthma and other breathing difficulties. Focusing on older age groups, it also assesses whether there is a relationship with the development of Parkinsonism and dementia. Additionally, the project examines the effect of maternal exposure to ambient air pollution during pregnancy on birth outcomes. An additional aim of this project is to raise awareness about the levels and effects of air pollution in NI among policymakers and the public. To achieve this goal, an online air pollution dashboard for NI will be used, and this will be updated and expanded to include the latest data as it becomes available.

 

Data

• Northern Ireland Longitudinal Study (NILS), NISRA
• Distinct linkage of NILS to the Enhanced Prescribing Database (EPD), HSC Business Services Organisations
• Northern Ireland Maternity Services (NIMATS), HSC Business Services Organisations
• Modelled air pollution background concentration data, Department for Environment, Food and Rural Affairs (DEFRA)

In the Northern Ireland Longitudinal Study (NILS) data, individual-level health metrics encompass self-reported health status from the 2011 Census and mortality events documented by the General Register Office (GRO) for Northern Ireland. By linking the NILS with the Enhanced Prescribing Database (EPD), prescription records sourced from routinely collected administrative data become available for analysis, including GP-dispensed medications for treating cardiovascular and respiratory illnesses, dementia, Parkinsonism, and diabetes.

Pollution exposure is quantified by the annual average ambient air pollution levels at an individual's area of residence, using data modelled for DEFRA at a 1x1 km grid square resolution for up to eight pollutants spanning the years 2001 to 2019. This allows the construction of cumulative pollution exposure measures for individuals in the study.

Additionally, these pollution data will also be linked to data from the Northern Ireland Maternity Service (NIMATs), which provides a wealth of demographic and clinical information on mothers and infants, encompassing factors such as infant birth weight and the mother's medical and obstetric history. Maternal exposure to pollution is determined by the annual average ambient air pollution levels at the mother's postcode address during pregnancy.

The combination of these linked datasets offers a robust framework for exploring the intricate relationship between individual health, prescriptions, and the impact of ambient air pollution in Northern Ireland from 2001 to 2016.

 

Potential

This project aims to provide the first comprehensive estimates of the individual-level health costs associated with air pollution in NI, considering a diverse range of health outcomes applicable to all stages of the life course.

Leveraging linked prescriptions data, the study will examine the effects of pollution exposure on childhood respiratory illness together with lesser studied health conditions such as diabetes, dementia, and Parkinsonism among adults. Furthermore, the investigation delves into whether infants born to mothers residing in areas with higher pollution levels during pregnancy experience earlier births and lower birth weights compared to those in less polluted areas, aligning with the policy objectives outlined in the Northern Ireland Draft Programme for Government, which prioritize improving air quality and birth outcomes.

Overall, this project serves to inform policymakers on the extent of air pollution reductions necessary to enhance population health in the region.

 

The Updates

• The research team has developed an interactive air pollution map of Northern Ireland which allows users to explore how levels of air pollution in their local area have changed through time and how they compare to pollution levels in other parts of Northern Ireland. This tool empowers the public to understand the levels of air pollution in their communities and how this could impact their lives.
• A Data Insight on The Effect of Exposure to Air Pollution on Health and Mortality was published early in the life of the project.
• A working paper examining the effects of in utero PM2.5 exposure on infant health was published in 2022. This paper provides the first assessment of infant health effects for NI.
• A working paper examining the effects of long-term PM2.5 exposure on self-reported health in adults was published in 2024. This paper provides the first assessment of health effects for adults in NI.

 

Project Details

Project Lead: Prof Duncan McVicar

Project Team: Dr Babak Jahanshahi, Dr Corina Miller, Dr Mark McGovern, Dr Neil Rowland and PhD Jason Fleming

Steering Group Members: NI Department of Health, NI Department of Agriculture, Environment and Rural Affairs, Belfast City Council, British Heart Foundation, Asthma + Lung UK and Alzheimer's Society.

Duration: Due for completion in 2026

Contact: ADRC NI office

Funding: This project is funded by ADRC NI from its core grant from the Economic & Social Research Council (ESRC) via ADR UK.