Air quality is an important consideration in the design of our environment, especially in care settings where the opportunity to go outside or open a window may be limited. Overall health can be adversely affected or pre-existing conditions further exacerbated due to poor air quality and therefore it is essential that buildings are designed with good ventilation to increase the comfort and wellbeing of all building occupants. Our guide to air quality for people with dementia provides useful information to assist designers, specifiers and operators of such environments, to ensure the comfort of the user is considered.
There have been many studies on the effect of air pollution on the lungs and heart, however more recent studies have focussed on the impact of air quality and the effect on the brain.
A study by Grande et al (2020) established that long term exposure to air pollution can be linked with a higher risk of dementia, with cardiovascular disease appearing to magnify the negative correlation with cognitive decline. The study was based in Stockholm where current regulations are stricter than the European limit and those of the US. However harmful effects were still recognised at levels below present EU standards.
A systematic review of the evidence base linking air pollution and dementia was undertaken in 2019 by Peters et al. Of 3720 records, 13 were seen to be relevant covering studies from the UK, US, Canada, Sweden and Taiwan. As perhaps already widely known, the review concludes that air pollution is a global issue, detrimental to health and is not the only contributing factor to cognitive decline but rather increases the risk of several non-infectious diseases.
A study in Taiwan in 2015, looked particularly at the effect of long term exposure to ozone and particulate matter in relation to Alzheimer’s disease. This cohort study of 95,000 people also resulted in a link between air pollution and increased risk of Alzheimers.
Andrée, a researcher at the VU University in Amsterdam has published a recent study on the impact air pollution has on the risk of transmission of viral respiratory infections, namely COVID-19 and found that the risk is raised in the presence of high particulate matter. This is potentially due to worse respiratory health in those who have lived in higher polluted areas and a particularly interesting discovery which may affect care homes based on their location.
Across the world, pollution levels have significantly dropped due to countries in lockdown and people using far less road and air transport. According to ‘Air Quality in Scotland’, nitrogen dioxide (NO₂) emissions have reduced by ‘between 51% and 81% from previous years’ and although particulate matter is harder to survey, it too has shown reductions.
While conclusive evidence regarding the association of air pollution with dementia is in its infancy and many contributing factors such as exposure over a person’s lifetime, age, gender and obesity are also evidenced to impact on an individual, research is showing a trend which links the two.
Air Quality and Dementia
Moulton and Yang’s study (2012) evidenced that particulate and ozone exposure was one of the contributing factors to developing some types of dementia. Particulates can be found in common domestic items such as household sprays; within damp areas, for example kitchens and bathrooms where moulds are more prone to grow; or through combustion of fossil fuels, with a major source being road pollution. Furthermore, air quality can be affected by temperature, humidity levels, contaminants and pollutants.
Older people are also more vulnerable to infections, respiratory diseases, and dehydration and impaired thermoregulation are also more common. Combining these health conditions with stagnant indoor air, (and potentially for the person with dementia, who may not be able to recognise, express or communicate their feeling of discomfort) can provide an unhealthy and distressing living environment.
Therefore it is vital that the site, orientation of a building and location of rooms should all be fully considered in the planning stages. Developing a hierarchy of spaces in relation to their ventilation needs can provide useful insight into locating rooms throughout the plan. Close proximity to certain species of trees has also been recognised to improve air quality by removing harmful gases and particles. However, care should be taken so that species creating high levels of pollen are not introduced.
Further consideration should be given to the specification of building materials as these often lend themselves to humidity fluctuations or off-gassing. Products containing volatile organic compounds (VOC’s) such as carpets, paint and laminates, can be associated with cancer, dizziness, respiratory tract irritation and nausea. Selecting low VOC products, increasing ventilation in the initial ‘bedding-in’ period and allowing products to ‘air’ before installation, can all reduce the rate of off-gassing.
To improve air quality and thermal comfort, buildings often use a mixed-mode ventilation strategy to optimise both natural and mechanical ventilation. They should reflect the external qualities in location, orientation and season and use natural ventilation whenever conditions allow. Window design is also very important, as they play multiple essential roles, from ventilation, to allowing natural light into an internal space. They can affect acoustics, energy consumption and also need to be safe and secure. UK building regulations also state that window restrictors with a maximum opening of 100mm should be installed on any opening which a person could potentially fall from, greatly reducing natural air flow through internal spaces. Therefore it becomes of more importance to allow the building user some control. Control over the internal environment provides psychological satisfaction and should be simple to understand, operate and maintain.
As people campaign to ‘build back better’, post the COVID pandemic, it isn’t a surprise that our environment and sustainability is a hot topic for discussion. For the person with dementia it is particularly important that the built environment enables independence and does not contribute further to health conditions. Paying attention to global topics such as these, to reduce carbon emissions and enhance our existing housing stock, will provide healthier, accessible environments for us all and could help sustain healthy cognition as we age.
To find out more about the impact of air quality, we’ve added a brand new presentation to our online ‘Intersection of Dementia + Design’ course.
Or to read more about air quality and health for people with dementia, our publication is also available at the John Smith website.
Air Quality in Scotland (2020) COVID19 lockdown – Time Variance analysis of air quality in Scotland [Internet] Available: http://www.scottishairquality.scot/ [Accessed on 30 July 2020]
Andree. Bo Pieter Johannes  Incidence of COVID-19 and Connections with Air Pollution Exposure: Evidence from the Netherlands [Internet] Available: http://documents.worldbank.org/curated/en/462481587756439003/Incidence-of-COVID-19-and-Connections-with-Air-Pollution-Exposure-Evidence-from-the-Netherlands [Accessed 4 June 2020]
Grande, G., Ljungman, P., Eneroth, K. et al (2020) Association Between Cardiovascular Disease and Long-term Exposure to Air Pollution With the Risk of Dementia [Internet] JAMA Network. Available: https://jamanetwork.com/journals/jamaneurology/fullarticle/2763459 [Accessed 4 June 2020]
Peters, R., Ee, N., Peters, J., Booth., A., Mudway, I., Anstey. K (2019) Air Pollution and Dementia: A Systematic Review. Journal of Alzheimer’s Disease 70(2019)S145-S163 [Internet] Available: https://pubmed.ncbi.nlm.nih.gov/30775976/ [Accessed 28 May 2020]
Thomson. K, Halliday. S, Utton. D, Pollock. A. (2016) Air quality and health for people with dementia. Stirling: DSDC, University of Stirling