down angle photography of red clouds and blue sky

Air is Life

While the current debate over the human diet seeks to settle the question of optimal health, both for the individual and for the planet (keto? veg? local?), few realize what a significant role the air we breathe has on our overall health. The fact that we can’t see, and can only vaguely smell the quality of the air we breath, means that we are more or less blind to its quality. With new digital tools however, all of this is about to change, but first, a brief primer on Air Quality:

Carbon and Oxygen

Air is also a kind of food, ingested or rather inhaled and exhaled daily by almost every living organism on Earth. Humans inhale about 10,000 to 20,000 litres of the stuff per day (depending on activity levels), and we actually chemically consume about 0.84kg1 of Oxygen in a day and exhale about 1kg of CO2. Interestingly enough, when we ‘burn fat’, according to the British Medical Journal2 – that is where it goes – we literally exhale it away.

Fig 2 When somebody loses 10 kg of fat (triglyceride), 8.4 kg is exhaled as CO2. The remainder of the 28 kg total of CO2 produced is contributed by inhaled oxygen. Lungs are therefore the primary excretory organ for weight loss. (This calculation ignores fat that may be excreted as ketone bodies under particular (patho)physiological conditions or minor amounts of lean body mass, the nitrogen in which may be excreted as urea)

Now we can’t survive for more than a few minutes without oxygen, so thankfully there is a  vast abundance of the stuff in our atmosphere. The fact remains however that we breathe many more components of trace gases, and it is the pollutants and particulates at these fractions of percentages that can have some of the most pronounced effects on our health.

Carbon Dioxide has been dominating the headlines, and rightly so. At its proper atmospheric concentration of approximately 300ppm (only 0.0003% of our atmosphere), it fulfils a pivotal role in the exchanges and regulation of climate and life on Earth. However, we have added an additional 110ppm to date, and by the end of this century, unless we take drastic action, we might even see this current level of 410ppm rise to over 1370ppm3. Now normally CO2 is not considered or classified as a ‘pollutant’, but this needs to change. In fact scientists have lobbied all over the world to classify and monitor CO2 as a pollutant for the very reason that it threatens the survival of life on the planet as we know it, but also because at levels above 600pm it becomes toxic to life, and we are seeing this play out with elevated concentrations in the oceans already.  One of the seldom discussed aspects of increasing atmospheric CO2 is the adverse effects it has on human health (PDF)4. At concentrations of 800ppm, we see the onset of what is known as Sick Building Syndrome or SBS, and with every increase of 300ppm above baseline we see a 10% decrease in our cognitive abilities.

As part of a larger study that included volatile organic compounds (VOCs), Allen et al. (2016) found that, after CO2 was independently modified (from a baseline of 480-600 ppm) for individual 8 hour exposures, cognitive function scores were 15% lower at 950 ppm and 50% lower at 1400 ppm” 4

A typical Air Quality Measuring Station in the Province of Ontario, this one is just down the street from us, CO2e measurements are absent from these readings.

It should be hysterically alarming that we continue to operate on the basis that even in spite of the catastrophic effects of climate change, almost nobody is discussing the severe toxic effects of these elevated concentrations of CO2 in the entire atmosphere, where there is no safe place to escape from it. One can quit smoking, but one cannot quit breathing! Cognitive decline is only the first, immediate effect of increased CO2 concentrations, there is a long list of additional effects that kick in over longer durations of exposure. At present (here are live streaming results5 for Ontario) we measure a range of outdoor air ‘pollutants’, but CO2 is not among them.

This really needs to change. In fact under President Obama, Lisa P. Jackson resigned6 in 2012 as head of the US EPA over this very issue, and remember Obama was considered the progressive president. The first step towards correcting harmful action is to acknowledge the harm, by accepting the truth of it. Action can only follow this acceptance, but we still have not taken that essential first step. As individuals and as nations we are still mired in debate and denial, and as my son recently wrote on his poster for a Fridays for Future climate protest, “Climate Change Won’t Deny You”.  National governments around the world are losing the moral authority to govern. This is where children like Greta Thunberg7 have felt compelled to initiate a movement of millions, and citizen science combined with local, municipal governance are the first to recognize the truth of our predicament and to take action. At what point do we think oil companies will agree to sit down together and set a ‘safe’ level of CO2 in the atmosphere? Could anyone agree and continue to do business claiming that 600pm is not harmful? Or 800ppm?  To claim “but we didn’t know” is no longer an option.

The Guardian8 has just started to add CO2 levels to its weather reporting, governments that are serious about tackling this issue will soon follow suit.

Now if atmospheric levels of CO2 are problematic, the more confined a space is, the more pronounced the effects. Buildings typically have 5 to 10x the levels of pollutants than the outdoors9. The CO2 in my own house can range between 600 and 1200 pmm on any given day. Airline cabins see even higher concentrations, cars moreso, submarines even moreso, and as atmospheric concentrations increase, so too do indoor concentrations. Beyond 800ppm we see symptoms of “headaches, dizziness, fatigue, respiratory tract, eye, nasal and mucous membrane symptoms…” and at 1000ppm, “Oxidative stress and damage to DNA in bacteria (implications for cancer diseases in humans)” not to mention “Harmful changes in respiration, circulation, and the cerebral cortex“(Bierwirth)4

Again, the first step is to recognize the problem, action can only follow.


It is a well accepted fact by now that smoking causes cancer. But did you know that the second leading cause of lung cancer is Radon10? Radon is a naturally occuring gas that is created by the decay of Uranium in the rocks and soil around you, and it tends to accumulate in the still air of indoor environments. Radon can be easily dissipated from indoor air using a few different approaches and systems11, but how would you know if your house or building has a Radon problem? We’ll get to that.


Lastly we can look at the VOC’s or Volatile Organic Compounds. Unlike the dust that one sees when sun streams through your windows, VOC’s are much finer particulates. So small they move easily with atmospheric gases. They can be introduced to indoor air by solvents and old paint cans (even stored with the lids on) household cleaners and detergents, fabric softener sheets, scented candles, off-gassing of fabrics, upholstery, adhesives, caulking and even building products. They tend to spike up when you cook or if you smoke or burn incense.  It is not uncommon to see TVOCs (Total VOCs) in a range of 200 ppb (parts per billion) to 1200 ppb in any given residence. The combined influence of Radon, CO2, TVOC and other indoor air pollutants can have pronounced effects on long-term health, from restlessness and sleeplessness, to cognitive decline and a greater susceptibility to cancers.

Visual IAQ Data Monitoring

As an architect specialized in ecological and ‘airtight’ buildings with controlled, continuous ventilation systems, the use of healthy and natural materials has become an established practice in our office. The use of Heat Recovery Ventilators is now mandated in almost all new buildings, and so better rates of air exchange can maintain a healthy level of O2, CO2 and dilute indoor concentrations of other pollutants. So while we have been measuring air quality for decades in our projects, the data-logging equipment is expensive and thus inaccessible to the general public. Because of this and the high cost of performing IAQ (Indoor Air Quality) studies, few people except in extreme cases of asthma or with chemical sensitivities are motivated to undertake these studies, and so those with lesser means, or in existing buildings, or in buildings they do not own, bear the brunt of not really knowing what might ail them. That is why, when we discovered a new product by Airthings10 of Norway that measures these key IAQ indicators, we were more than a little enthusiastic to get our hands on the device. The unit, called an Airthings Wave+ is the size and shape of a smoke detector, and measures IAQ to a surprisingly high tolerance. Airthings started out as Corentium, a company that designed and built Radon measuring devices for the professional market. Then they introduced a consumer-grade model called the Wave, and followed up with the Wave+ when they realized a number of sensors could be packed into the same format.

Airthings Wave+ as a Control Unit

The unit syncs to any smart device, phone or tablet via Bluetooth, and feeds this data to Airthings server and your own ‘Dashboard’ view on a website or in the Airthings App. This interface (see below) also lets you set threshold warnings, that not only indicate when certain safe levels of a given indicator have been breached, but through IFTTT (If This Then That) triggers can be easily scripted to run furnace fans, or HRVs, or Radon extraction fans until safe levels have been restored. This level of smart building controls can cost a fortune and is typically only available for big, complex commercial buildings with state of the art systems. Here in our house, we have it connected to a Nest Thermostat. If you want HRV control you can connect with an EcoBee4 smart thermostat. Smart controls are finally available to ordinary consumers.

As a homeowner, it is a real eye opener when you can get this level of insight into your IAQ.  As a design professional, it is an amazing way to log visual data at any time scale on recently completed buildings. We use the dashboard app to review the efficiency of our systems, from passive solar design to HRV effectiveness.  Here are some samples of data from one of our recently completed projects:

What you can see from the Airthings Dashboard for a given period of time. This is from a recently completed passive-solar steel building we designed with all natural materials. As an above grade structure with mechanical ventilation, we can see that Radon is not an issue. TVOCs tend to spike up when cooking takes place, but falls to within acceptable limits otherwise. CO2 was somewhat elevated after we switched off the HRV for a period of time to establish its effect on heat-loss. Humidity is within tolerance. Temperature is a function of the designed set-point, and humidity is within tolerance. This is an almost perfect house.

Now, take a look at my home-office, which is located in a beautiful if not-so-efficient mid-century bungalow with a walk-out basement, but with plenty of sub-grade or soil contact, so the Radon count is often higher than is considered safe in Canada.

Airthings data from this week at our Home-Office: Elevated Radon (routinely over 200 Bq/m3), Elevated TVOC (tends to spike at rush-hour, we live next to a major highway), High Levels of CO2 (we don’t have a ventilation system), Humidity within Tolerance, Temperature within tolerance (we set our thermostat low to save energy). Unfortunately quite far from perfect. We have work to do here!

Control and Quality

One can start to see the emergence of patterns. For example a big dump of fresh snowfall pushes soil gases up into the house, Radon peaks for up to 8 hours. Or the periodic spiking in temperature you see in our house, which is a function of our furnace ‘short-cycling’ or ‘porpoising’ because it is oversized for the ductwork and relatively small space that it is heating. We can also study passive solar gains that creep upwards from 12 noon to 4pm and coast to 4-6 degrees above baseline temperatures until 8pm opr so on sunny Winter days. We can also see the distribution of heat-loss and loads between rooms to get better insight into how to optimally damper and zone our buildings for more even distribution. We can also set the HRV and ventilation equipment to run only as needed (ie. after 600ppm has been reached) instead of operating continuously as it is typically designed to do, and this offers a significant opportunity to lower total energy costs.

This is a game-changer for us as architects, and it will be very important for those suffering the health effects of poor sleep, high blood pressure (due to reduced O2 intake from physiological feedbacks that reduce breath-rate as a function of CO2 concentration), asthma and other conditions related to poor Indoor Air Quality. First of all, we can learn whether the symptoms we may be experiencing are related to our indoor environments. Then we can then take control and design an effective ventilation and/or filtration system as required, or at the very least, change some filters, open a window, or get outside for some fresh air! You may be noting at this point the conspicuous absence of any discussion here of Methane, NO2, SO2 and other particulates (ie. from wildfire smoke) over PM2.5, I hope to expand this article at a later date, but only mention here that their effects are also significant and the exclusion is only in the interest of brevity at the moment. In the resources section below (14-16) you can see that at least these pollutants appear to be receiving appropriate media coverage. 

Public Policy & Conclusion

What is needed is a 3-part plan in public policy;

  1. Awareness and public data of all IAQ and OAQ measures, specifically carbon dioxide, ie. weather reports including CO2 levels, public web-dashboards, etc.
  2. Increased funding for Public Research on the health effects of all IAQ and OAQ gases and particulates, especially long-term effects of CO2 on human and animal health (ie. on submariners, pilots, etc).
  3. Establishing CO2 as a pollutant among other GHG gases, and setting limits for safe levels in the environment

Most importantly of all, we feel that a daily, visceral awareness of the measure and quality of our air, and especially the concentration of CO2 in our atmosphere, is a critical first step in recognizing the truth that all life depends on a high quality of air in a balanced proportion, because quite literally, Air is Life.

References & Resources:

  17. Nanoparticle Microplastics:
  18. NO2: The Lancet:
  19. Alzheimers and OAQ:
  30. Effect of occupant-induced indoor CO2 concentration and bioeffluents on human physiology using a spirometric test

  31. Central respiratory chemosensitivity and cerebrovascular CO2 reactivity: a rebreathing demonstration illustrating integrative human physiology



  1. Architects, Air and SarsCov2 – thomson | architecture inc. left a comment on January 14, 2021 at 2:45 pm

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