Does poor air quality contribute to 800 deaths in Northern Ireland every year?

• 2020 research estimated that each year around 800 deaths in Northern Ireland are attributable to air pollution.
• The most recent academic research (2023) suggests that the figure is higher: 900 premature deaths in NI attributable to fine particulate air pollution.
• Per head of population, NI has more deaths attributable to poor air quality than Ireland.

The SDLP manifesto for the 2024 General Election claims that “poor air quality contributes to 800 deaths in Northern Ireland every year”.

We’ve looked at the data, and this is accurate. 

The figure quoted by the SDLP is from research published in 2020. A more recent analysis estimates that the number is slightly higher, and that 900 premature deaths in Northern Ireland are annually attributable to exposure to fine particulate air pollution.

The figure for Northern Ireland is higher than the rest of the island, when population size is taken into account.

• Source of information

FactCheckNI asked the SDLP about the source of their claim and they pointed to a 2020 article in the Belfast Telegraph.

It discussed the then Environment Minister Edwin Poots MLA launching a discussion document about a Northern Ireland Clean Air Strategy. The related Department of Agriculture, Environment and Rural Affairs (DAERA) press release included a quote from the head of the British Heart Foundation Northern Ireland, Fearghal McKinney, saying “each year around 800 deaths in Northern Ireland are attributable to air pollution, with a significant impact on heart and circulatory health”.

This figure was derived in 2019 from the Global Burden of Disease dataset that is maintained by the University of Washington School of Medicine’s Institute for Health Metrics and Evaluation.

However, a more recent academic research paper – produced by Technological University Dublin and Queen’s University Belfast, commissioned by Irish Heart Foundation, British Heart Foundation Northern Ireland and funded by Community Foundation Ireland – updates the analysis.

• A quick science lesson about air pollution and health

FactCheckNI believes that it is important that readers can reproduce the figures behind a claim, starting with the source data, and following the steps we’ve followed  in the process to validate what has been claimed.

In the case of air pollution and health, the science is complicated, and the process is a multi-stage statistical one. We’re satisfied with the veracity of the source information that we’ve relied upon. But it does require more trust than usual: in this case, trust of peer reviewed research and widely used methods of analysis in this sector of epidemiology.

• What’s the science about air pollution and its link to poor health?

Strap yourself in. At its simplest …

People don’t die of air pollution. It’s not an immediate poison. Instead, poor air quality has a detrimental impact on your health.

Summarising a much more detailed section providing context in the 2023 Air Pollution and Mortality on the Island of Ireland report and Guidance on Air Pollution from the Office for Health Improvement and Disparities (formerly Public Health England), we learn:

• Air pollution can come from naturally occurring sources like forest fires, pollen, and volcanic eruptions. But it also comes as a byproduct of human activity – ‘anthropogenic’ air pollution – such as the combustion of fossil fuels, domestic heating systems, particularly those that burn coal, wood or turf. While you can be exposed to these fine particles within the home or an indoor work environment, research focuses on outdoor air pollution.
• “… every time we burn something we are releasing particles into the air which are damaging to health.”
• The fine particulate matter (known as PM_2.5) which can be breathed in by humans are small enough to enter the lungs, and from there make their way into the bloodstream. Prolonged exposure to such particles can eventually lead to damaged pulmonary and cardiovascular systems. These harmful pollutants can narrow and harden blood vessels, leading to abnormal heart rhythms, increased blood pressure, and an increased risk of fatal heart attacks and strokes.
• The World Health Organisation (WHO) lists poor air quality as one of the world’s leading causes of avoidable disease and premature death, attributing 4.2 million deaths worldwide per year to exposure to outdoor air pollution.
• In particular, the WHO estimates that in 2019, some 37% of outdoor air pollution-related premature deaths were due to ischaemic heart disease and stroke.
• Reducing fine particulate matter pollution levels would reduce levels of morbidity (the state of being unhealthy for a particular disease or situation) as well as reducing mortality (the number of deaths that occur in a population).

It is important to stress that when researchers make estimates of premature deaths, they are not giving a direct headcount on the number of deaths that actually occurred in an area because of PM_2.5 exposure. Rather, they are indicating how the level of PM_2.5 air pollution in that region leads to an increased mortality risk in the local population by an amount equivalent to a particular number of deaths.

In the case of the island of Ireland, studies draw together:

1. pollution exposure data across regions from the European Environment Agency (EEA);
2. regional level mortality data from Northern Ireland Statistics & Research Agency (NISRA) and the Central Statistics Office (CSO) but excluding deaths due to ‘external causes’ like accidents, homicide, suicide, etc;
3. estimates of the proportion of deaths in each region that can be associated with long-term exposure to ambient PM_2.5 air pollution from the Committee on the Medical Effects of Air Pollutants (COMEAP) statement on quantifying mortality associated with long-term exposure to PM_2.5 which involved a meta-analysis of global research.

Data from 2019 is used by studies because it is the most recent year with data available that is unaffected by COVID-19.

The 2023 study we rely on in this fact check also looks at the subset of deaths due to circulatory-related diseases.

• What’s the figure for Northern Ireland?

The European Environment Agency data about regional particulate concentration can be broken down by council area. Belfast has the highest 10.1 μg/m³ , followed by Antrim and Newtownabbey (9.4). Levels are estimated to be lowest in Fermanagh and Omagh (7.4).

Looking at Northern Ireland as a whole, and Ireland for comparison:

Source: Adapted from Tables 1 and 2 in Air Pollution and Mortality on the Island of Ireland report (2023)

The researchers “estimate that approximately 1,700 premature deaths (680 from cardiovascular disease) in Ireland, and 900 (with 300 from cardiovascular disease) in NI are attributable to exposure to fine particulate air pollution”.

The researchers acknowledge that these new “mortality estimates are higher than those published by the European Environment Agency (EEA) or the Global Burden of Disease Study for ROI in 2019, and by either Public Health England (PHE) for NI in 2010 or the Global Burden of Disease for NI in 2019. This reflects our use of updated dose response functions based on growing research evidence that exposure to PM2.5 is more harmful than previously thought.”

• Is air pollution bad in Northern Ireland?

To compare across different populations, we need to standardise the results.

The mid-year estimate for Northern Ireland’s 16+ population in 2019 was 1,529,994. ROI’s total population in 2019 was 4,921,500 and its 15+ population was 3,912,600.

These figures allow us to calculate a comparable statistic for attributable deaths per 100,000 population.

Northern Ireland has a higher number of attributable deaths due to fine particle air pollution per 100,000 of population than the Republic of Ireland.

Researchers analysed the data across the island of Ireland by council area.

Northern Ireland local government districts make up 6 out of the top 10 – and the top 4 overall – across the island of Ireland. Cork and Dublin City Councils are the highest areas in ROI.

• What can be done to improve air quality and reduce premature deaths?

Policy work following the DAERA’s Clean Air Strategy Discussion Document consultation has been slow. The other UK nations have published Clean Air Strategies but only England has banned the sale of some materials.

In May 2021, England introduced restrictions on the sale of wet wood for domestic burning, limits on the emission of sulphur and smoke from manufactured solid fuels, and began to phase out the sale of bituminous coal.

The Welsh Government’s policy objective is to avoid the continued extraction and consumption of fossil fuels. They plan to develop legislation to restrict the sale of bituminous house coal, wet wood and manufactured solid fuels and this is expected to progress during this Senedd term [will finish by May 2026].The Scottish Government’s Cleaner Air for Scotland (CAFS2) strategy is investigating a “ban on the sale of house coal and of manufactured solid fuels with a sulphur content greater than 2% for domestic use”.