Lancaster research finds open fires could pose substantial hazard to brain health

An open fire

Collaborative research led by Lancaster University uncovers cognitive impairment in older people associated with use of open fires in the home.

Findings of the study, conducted by Lancaster University and The Irish Longitudinal Study on Ageing (TILDA) at Trinity College Dublin, reveal that open fire usage negatively impacts cognitive health, with adverse association largest and strongest among women – a consequence of women of that age group typically having spent more time at home, with greater exposure to open fires.

The study was focused on Ireland where there are far greater numbers of open fire users than in other Western European countries. Close to 7,000 people, aged 50 and over, participated in the study, and cognitive decline was estimated by widely-used cognitive tests including word recall and verbal fluency.

The research, published in the journal Environmental Research, follows government regulations implemented in Ireland earlier this year, which banned the use of smoky coal in all Irish towns with populations over 10,000 people. The regulations became law in July 2020, in an attempt to reduce air pollution in the country, promote public health and improve health outcomes.

Professor Barbara Maher, joint lead researcher from Lancaster University, said: “Indoor air pollution forms when soot, particles and gases linger in the air inside a building, affecting the quality of the air inhaled into the lungs – the finest particles can even enter the brain directly through the olfactory nerves. We know that exposure to indoor air pollution affects both respiratory and cardiovascular health, but, before now, little was known about how it affects cognitive function in older adults.”

Previous studies revealed that air pollution is linked to harmful health conditions such as stroke, heart disease and lung cancer, as well as chronic and acute respiratory diseases like asthma. Now, a growing body of scientific evidence indicates that exposure to airborne particulate matter (from industrial, domestic and traffic sources) is associated with damage to neurodevelopment and cognitive function, contributing to neurodegenerative diseases around the world. Coal fires are one of the largest sources of fine particulate matter (PM2.5); the smallest of these air pollution particles can find their way into the lungs and then the bloodstream.

Examining concentrations and magnetite content of airborne particulate matter (PM) that arise from burning peat, wood, or coal in open fires in the home, the study sampled close to 7,000 older people from the TILDA dataset. Findings reveal:

  • Peat-fuelled open fires emit higher particulate matter (PM) concentrations than coal and wood fires
  • Magnetic content in particulate matter emitted from open fires is similar to that of roadside particulate matter
  • Exposure to particulate matter from indoor open fire usage is similar to outdoor commuting exposure
  • There was a negative association between open fire usage and cognition among older Irish people.

Professor Maher said: “We discovered that the level of exposure to particulate matter from open fires is comparable to and may well exceed the levels people are exposed to from roadside sources. This is very concerning, not only for elderly people but especially for those who stay at home during the working day and use coal in their open fires.”

Dr Vincent O’Sullivan, joint lead researcher from Lancaster University Management School, said: “This collaborative study has found strong evidence of the health risks that open fire usage poses not just to older adults, but to people of all ages. We provide evidence that outlines the health risks open fires pose to cognitive function, and supports policies banning or restricting the use of open fires as a heat source, for example the UK government’s announcement earlier this year to phase out coal and wet wood use in 2021. Traditionally, public health concerns about air pollution have been raised in relation to its negative effect on the heart and lungs; our research however demonstrates why cognitive function should be a key concern for policymakers to address, especially in Ireland, where open fire use is very common.”

Professor Rose Anne Kenny, Principal Investigator of TILDA, and Head of Medical Gerontology at Trinity College Dublin said: “Open fires that burn coal and peat are a feature of many homes across the country, yet indoor air pollution remains a risk factor for many of the world’s leading causes of death, such as heart disease, pneumonia, stroke and lung cancer. Reducing dementia and cognitive decline remains a key goal for global healthcare systems. This research provides a body of evidence for public health and environmental policymakers to examine the risks that open fires pose to the cognitive health of older people, and greater scientific evidence to reduce fossil fuel use as a heat source in favour of cleaner, climate-friendly alternatives.”

To view the full paper, ‘Indoor particulate air pollution from open fires and the cognitive function of older people’, visit: 

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