One Take #3 - Beyond the Comfy Chair: Home indoor air quality and cognitive function over one

Ever wondered why you sometimes struggle to focus when working from home? We dive into fascinating new research that connects the invisible elements of our home environments to how well our brains function during remote work.

This episode explores groundbreaking 2024 research fromAnna s. Young and colleagues  who monitored over 200 remote workers for an entire year, tracking how their home's air quality and temperature affected their thinking abilities. The findings reveal a surprising "Goldilocks zone" for optimal brain performance – with temperatures around 23°C (73°F) proving ideal for creative thinking and cognitive speed. Too warm or too cold, and our mental performance measurably declines. We also examine how carbon dioxide levels, even when relatively low compared to crowded offices, might still subtly impact our ability to think clearly and solve problems.

The implications extend far beyond personal comfort. As remote work becomes a permanent fixture in our professional landscape, these findings challenge us to reconsider what makes a truly productive home office environment. It's not just about ergonomic furniture and fast internet – the quality of air you breathe and the temperature you sit in could be making or breaking your workday. Could simple adjustments like opening a window or tweaking your thermostat give you a cognitive edge? Listen to discover practical insights for optimizing your home workspace for better thinking, focus, and creativity. Your brain (and your productivity) will thank you!

Home indoor air quality and cognitive function over one year for people 
working remotely during COVID-19

Chapters

• 0:00 Introduction to the Research Study
• 2:04 Study Methods and Participant Monitoring
• 4:01 Findings: Thermal Conditions and Cognition
• 6:25 CO2 Levels and Cognitive Performance
• 9:22 Key Takeaways and Study Limitations
• 12:26 Implications for Remote Workers

Transcript

Simon: 0:00

Welcome back to Air Quality Matters and One Take One Take, my take on a paper or report on air quality, ventilation and the built environment. One Take in that it's well in one take and usually takes about 10 minutes or less, because who has the time to read all these amazing documents? Right? This week we're diving into what I think is a really interesting piece of research, especially when so many of us are still working from home, at least some of the time. It's a study published in Building an Environment in 2024 by Annie Young and a team from places like Harvard and Emory. The title is Home Indoor Air Quality and Cognitive Function Over One Year for People Working Rem working remotely during COVID-19. Essentially, they asked does the air in our homes actually affect how well we think and perform when our home is our office, and what can we do about it? It's a question I think many of us have probably wondered about at some point, especially on those days when focusing feels like a bit of an uphill battle. It's not without its limitations this work, but I think it's a starting point for very.

Simon: 1:12

The COVID-19 pandemic, as we all know, massively shifted how many office workers operate, suddenly turning our homes into full-time workplaces, but our houses weren't really designed as offices, were they? Many were built with different priorities in mind. Offices were they? Many were built with different priorities in mind. So this research is pretty critical in understanding if these home environments are actually up to the task, particularly for our brain power when they're pulling double duty. So what did they do? Well, it was quite a comprehensive study in that regard and pretty cleverly designed for the circumstances. They followed over 200 office workers across the US for a whole year, between 2021 and 2022, while they were working remotely or in a hybrid setup.

Simon: 2:15

These participants had a couple of real-time, albeit consumer-grade air quality monitors in their home workstation areas and also in their bedroom, tracking things like carbon dioxide, temperature and relative humidity, and they used a custom built smartphone app, which I thought was quite neat, to take regular cognitive function tests Think tests like the Stroop test you know where the word blue might be written in red ink and you have to say the ink colour, not read the word or arithmetic challenges, and even creativity tasks like the compound remote associates task. The app was also geofenced, meaning it only let them take the tests when they were actually at home, which is a smart touch to ensure the environmental data matched the cognitive task location. The main things they looked at in terms of exposure were the level of CO2 and the heat index, which is basically what the temperature feels like to the human body when you factor in relative humidity in the 30 minutes leading up to each cognitive test. This 30 minute window gives a good sense of the acute environment someone is in just before they try to really focus. Interestingly, they had planned to look at fine particulate matter as well, but in most of these homes the levels were actually so low, often below the monitor's accuracy limits, that they couldn't really include it in the main statistical models, which in itself is an interesting observation about these particular home environments, perhaps cleaner in terms of particles than some might expect, or at least below the threshold of the specific sensors.

Simon: 3:59

All right, so what did they actually find? Well, one of the really big takeaways was about thermal conditions, that's, the heat index. It turns out it's a bit of a Goldilocks situation for our brains. Our cognitive performance doesn't fare too well if it's too hot or if it's too cold. The relationship wasn't straightforwardly linear either. Where, say, warmer is always better or always worse. Instead, it was more of an upside down U-shape.

Simon: 4:28

For some tasks, particularly creative problem solving, performance on the Stroop test and the creativity test tended to be poorer when the conditions were either too warm or too cold. For instance, when the heat index was below about 23 degrees Celsius, that's about 73 degrees Fahrenheit, a warmer environment was actually linked to better performance. On things like cognitive speed and creativity People did better. But once you got above that 23 degree mark, a warmer heat index started to be associated with worse creativity of thinking and was suggestively linked to a performance on the Stroop test too. So there's definitely a sweet spot, and straying too far either way seems to impact how we think.

Simon: 5:15

They also noted that temperature and relative humidity seems to interact in complex synergistic ways to affect our cognitive function. It's not just one thing or the other in isolation. This isn't entirely surprising if you think about it. Other studies in different settings have pointed to this non-linear effect of temperature. When we're uncomfortably hot or cold, our body is working harder to regulate its core temperature and that physiological stress can divert resources and attention away from complex cognitive tasks. What this study really does is bring that understanding firmly into the home working environment, which hasn't really been optimal, isn't a one-size-fits-all thermostat setting. Think about where I'm from and the Irish, who have a melting point of about 23 degrees. So the only thing anybody can think about around here when it gets above that temperature is where the nearest ice cream is. What's comfortable and productive for one person might not be for another, even in the same room.

Simon: 6:24

Now what about CO2? This is always a big one in indoor air quality discussions, often used as a proxy for ventilation, and in this study the CO2 levels in most homes were actually quite low and, I'd argue, very low, generally below 640 parts per million. Yeah, you heard me right. The median was around 632 parts per million across all the data collected by the monitors and about 678 parts per million in the half hour before the cognitive tests were taken 120 give or take, and well-ventilated indoor spaces often aim to be below 800 or, say, a thousand. So these are not dramatically high levels, the kind you might see in a crowd, crowded, poorly ventilated meeting room, for example. While it wasn't a slam dunk statistically significant findings across all the cognitive tests they run, the general trend for some of the Stroop and Creativity tests was that higher CO2 was associated with slightly worse performance. The authors themselves suggest that the generally low CO2 levels observed in this cohort of homes might be why they didn't see stronger, more definitive effects. And I have to agree. Many of the homes were single family houses with a median of just two residents, which often means more building volume per person and potentially lower CO2 build-up compared to, say, a densely packed open plan office.

Simon: 8:00

This is a common debate with CO2. Is it the CO2 itself causing the direct hit on cognition at these lower to moderate levels, or is it more of an easy to measure stand-in, a surrogate for a whole host of other indoor pollutants, or simply a lack of fresh outdoor air and therefore the build-up of human bioeffluents? The study doesn't definitively answer that for these homes, as they didn't measure those other pollutants in the analysis, but it leans into the idea that CO2 is at the very least a useful indicator for air exchange. And even if it is just an indicator, in this context it's telling us something important about the air quality that could be subtly chipping away at our cognitive edge. This lines up with other research in office buildings and classrooms, where higher CO2, even if not sky high has been linked to measurable dips in cognitive scores.

Simon: 8:58

So what's the big picture here for those of us turning our kitchen tables and spare rooms into command centres. Well, it really underscores that our home environment, when it's also our office, plays a tangible role in how effectively we can work, specifically in how well our brains function. It's not just about having a comfy chair and good internet connection. Those are important, of course, but so is the invisible environment, the air we're breathing and the temperature that we're sitting in. These things matter for cognitive speed, for our ability to focus, to filter out distractions and even for our creative problem solving. It's perhaps validation for those times you felt sluggish or unable to concentrate and you couldn't quite put your finger on why. Maybe it was all just a bit too stuffy or a tad chilly or warm. These aren't just subjective feelings. This research suggests that they can have a measurable impact, and this has implications beyond just us as individuals trying to optimise our own little work bubble.

Simon: 10:01

The paper suggests there's a real need to think about how we can enhance indoor environmental quality in our homes for people working remotely. There are benefits for both employees better focus, maybe less frustration and improved wellbeing and potentially for employers too, through sustained productivity and engagement. It's not just about ticking a box for an office building anymore. If the office is now distributed across hundreds or thousands of homes, what does that mean for ensuring a baseline level of environmental quality that supports work? It's a complex question for sure, involving aspects of building science, personal responsibility and perhaps even employer support, but one this paper certainly brings to the fore, and it strongly backs up a wider call for building standards and practices that aim for low CO2 concentrations and good thermal management, not just for comfort but for optimal health and cognitive function across all building types. So the key takeaway from this study by Young and colleagues is that thermal conditions at home not too hot or not too cold, that Goldilocks zone are clearly linked to our cognitive performance when working remotely. Getting that right seems pretty crucial, and while CO2 findings were more subtle in these typically low CO2 homes, there's a suggestion, a trend, that keeping CO2 levels down, likely through good ventilation and fresh air, is also beneficial for us, for our thinking power.

Simon: 11:35

Now the researchers are up front about the study's limitations. It was a specific group, highly educated, knowledge workers in the US, mostly white or Asian, so it might not apply to everyone everywhere or in different types of housing. The indoor air quality in these homes, particularly the PM2.5 and CO2 levels might be better than in lower income homes or different building types. So generalizability has its bounds and, as mentioned, they couldn't really dig into the pm 2.5 because levels were so low. But it's a robust study in real homes, not a lab, over long period of time in different seasons, which is a huge strength, and using objective indoor air quality measurements alongside objective cognitive tests is definitely the way to go.

Simon: 12:26

Ultimately, this research really makes you think, doesn't it? As remote and hybrid work looks set to stay for many becoming a permanent feature of the employment landscape, perhaps it's time we all as individuals, and maybe even as employers and policy makers, paid a bit more attention to the invisible environment of our home offices. It's about creating a home environment that doesn't just shelter but actively supports our well-being and ability to perform, especially when those lines between home and work are now so blurred. Perhaps a little more mindful management of our own home's air, opening a window and considering our heating and cooling, could make a bigger difference than we realise. Food for thought, indeed. That's all for this one take. Join us next week on Air Quality Matters for more, and don't forget to check out the sponsors in the show notes. See you next time.