The Historical Burden of Shared Air and the Future of Indoor Air Quality

What we breathe impacts our health, and with gaps in knowledge about air quality and public health, we need more data in this area.  We also need to consider the implications of Covid-19 which has highlighted that people can themselves generate contaminated air as well as toxins more usually considered in building design.

At the recent Healthy City Design congress Patrick Chambers of Stantec, Australia talked enthusiastically about the historical burden associated with public air and what understanding is needed for the future to better understand how it impacts public health.

Intuitively day to day, how do we know about health? We have a general understanding of our own health where you get immediate feedback, and you know that wasn’t very good for you. But there are other things which are very subtle that could be impacting our health that we do not know about. The only way we get a handle on that, is to look at this at a population level.  Epidemiology underpins this and supports making decisions about health based on behavioural and lifestyle inputs including through statistical methods, an early example of this being the work of John Snow leading to work to address water quality.  And, of course at the time our understanding of the role of breathing and air for health was less well understood.

Obviously, this relies on the data available about a given topic and in the case of air quality, we don’t have good quality data about air quality at this time especially at the individual level.  We know people are exposed to air pollution however little is known about the extent to which a person has been exposed at an individual level throughout their daily activities in different spaces and how that relates to their health and wellbeing.  So for example would it be clinically useful to understand someone’s exposure to air pollution when they present with say heart disease?  Globally, more people are living in urban areas, which changes both the exposures they are subject to and also the production of pollution itself.  

When you lose weight where does it go?

As a further demonstration of gaps in knowledge Patrick gave the striking example of the lack of understanding of the question: When somebody loses weight, where does it go?  The surprising answer is: 84% of the weight lost during a person’s lifetime will come out of their mouth and nose as carbon dioxide!  So, air even plays a role in the process of losing weight!

A paper published in 2014 asked physicians (people who we might expect to know!) this same question and the results showed most thinking, incorrectly, that fat is converted into energy. Patrick Chambers reflected how probably given this was the view from health practitioners, that many engineers and designers would have similarly large gaps in knowledge about links between health and air.

And if you want to understand the mechanism, think about this: the body digests fat or glucose molecules which are at a basic level are carbon, hydrogen, and oxygen.  Mechanisms in the body breakdown this down to allow oxygen into the blood and the blood then supplies this to tissues and tissues then release energy.  However, the balance of anything left (the majority) is carbon dioxide (CO2) (Meerman & Brown, 2014). Which in turn is exhaled via mouth and nose.

The broader point made is that there is a need to address this gap in health literacy when discussing air quality.  There are also potential areas to explore by applying engineering thinking to health issues, and Patrick Chambers was able to provide some fascinating and thought-provoking examples.

What is your air quality age?

As an engineer Patrick sees this as an issue related to partial pressures of carbon dioxide in the air people breathe.  Increased partial pressure measures of CO2 in the blood increase heart rate (for example when exercising).  This also increases blood acidity which is associated with certain increased health risks.  From an engineering perspective, he related this to an office example: if there is poor ventilation resulting in increased levels of CO2 in the workspace this may lead to slightly increased heart rate and blood acidity.  So would it be useful to consider this from a clinical perspective?  It would be useful to investigate this further.  In a historic context Patrick highlighted that we know outside air has a concentration of CO2 has increased from less than 300 parts per million (ppm) pre-1800 to typically 400-450ppm today.  But, consider an office environment that contains much higher levels of typically 800–1500ppm.

With more time being spent indoors Patrick posed the question – what is your air quality age?  In future we need to be smarter about this such as working out mean weighted CO2 exposure over the life-course.  A clear example of a question that requires joining up engineering and public health knowledge.

So how can we get better air quality inside buildings? From Patrick’s perspective there must be a continued emphasis on mainstream engineering strategies such as dilution of air; further measures such as comprehensive processing and filtration systems should also be looked including localised treatment of air; and not just supply of clean air but also extracting contaminants at source and considering the implications when people themselves are the ‘pollution sources’.  Stantec have undertaken significant work on understanding these strategies and the future of the ventilation industry.

Finally as a truly forward look Patrick pointed to the power of plants including bio-technology to create clean air in the buildings we spend an increasing amount of our lives in.

This session highlighted the need for joint working across disciplinary boundaries including engineering, public health, and medicine.  Also what is better for people is often good for planetary health.  As we spend more time indoors, by conducting further research, we can gather evidence to better understand the affect air quality has on public health in an urban environment, bridging the gap between public health and urban development.

Urban Habitats:

Here at Urban Habitats, working for change is exactly what we aim to do.  We use creative, inclusive, and evidence informed thinking to narrow knowledge gaps, increase understanding, and broaden the scope for the future of healthier places for both people and planet. 

Healthy City Design International: Research, Policy, Practice

Healthy City Design International Congress & Exhibition is a global forum for the exchange of knowledge on the research, policy and practice of designing healthy and sustainable cities and communities.  The theme of this year’s congress was: ‘Back from the brink: Designing for climate, community and social value’.  Urban Habitats is delighted to support the congress as Knowledge Leaders.