It started at a pretty-innocuous 642 parts per million. Seven minutes later, it hit 1,230.
Fifteen minutes into recording this episode, the carbon dioxide levels in our (very tiny) podcast studio reached 2,300ppm, about halfway to the 5,000ppm when the levels reach the beginning of the “CO2 poisoning” zone. And boy, were we feeling stupid. It was hard to finish sentences, let alone try to keep a structure for the episode in mind.
We shoved open the door, took a deep breath of normal air, and realized that our theory that the podcast studio’s lack of ventilation was making us dumber was 100% correct.
When a meeting goes badly, or when you have one of those days where you can’t get anything to go right, nobody ever blames the room. But in reality, factors like the insidious CO2 levels we experienced in our podcast studio, a sweltering room without AC in August, loud hammering on the roof next door, or a mismatch between the type of project you’re working on and the environment you’re working in are more than little annoyances. In fact, research shows that in many cases, environmental factors can be even more responsible for outcomes than the quality of the people and the processes they follow.
Today’s episode explores our working environment and how it impacts our productivity. From black-and-white factors like CO2 to situational factors like ceiling heights, we’ll help you figure out how to navigate setting up your environment to help you succeed in whatever project you’re working on.
The breathing baseline
One of the peace dividends from the COVID era is a new appreciation of indoor air quality. While we (mostly) are no longer wearing masks, researchers have continued to pay attention to how three factors, in particular, impact our productivity: CO2 levels, PM2.5 levels, and air temperature. And all three have a correct answer if you’re looking to optimize productivity, regardless of what type of task you’re working on.
For carbon dioxide levels, lower is better.
For some reason, most of the quality research on how CO2 impacts productivity has been done in Boston. Boston Public Schools built a system of 3,659 sensors across 125 buildings to find out how air quality affects school performance. They found that lower CO2 levels in the building resulted in a 13% increase in passing scores on exams – as big of a difference as substituting a skilled teacher for a poor performer. In their system, the average CO2 level was 841ppm, with peaks above 1,500 ppm.
Outdoor air is about 425 parts per million (which is already up from 280ppm in 1850 thanks to fossil fuel combustion). Research from Joseph Allen and collaborators at Harvard found that once you put people indoors, CO2 concentrations tend to increase quickly. Just one person in an average-sized office crosses 600ppm in 15 minutes and 1,000 ppm in 60-90 minutes. When more people are in a small room, like a big meeting in a conference room, it’s possible for CO2 levels to rise to near the level of early CO2 poisoning, at 5,000ppm. It’s not possible to make great decisions with that level of CO2 concentration, and we often try to make them right at the end of the meeting, when CO2 levels are at their highest.
The lowest-hanging-fruit solution? Usually, it’s to open a window. When there’s airflow into the room from outside, CO2 levels stabilize close to outdoor levels, which is as good as we can generally get.
But for over 100 million Americans this July, opening a window would have immediately created issues with the second most-impactful environmental factor: PM2.5 pollution.
PM2.5 pollution measures the concentration of pollutants that are 2.5 micrometers or smaller. That’s about 30 times thinner than a single human hair, and it is the size cutoff for particles that are small enough to be absorbed by our lungs and delivered into our bloodstream. The target level of PM2.5 is zero, and in addition to health impacts, PM2.5 impacts our decision making.
The air quality index (AQI) is a measurement of how much ozone and PM2.5 pollution is in your area. About a third of the air pollution from outside comes into the average indoor space. The best place I know to monitor local air quality is run by the EPA: https://fire.airnow.gov/
The strongest evidence of how PM2.5 impacts our productivity comes from a German chess tournament study. They found that as air quality worsened, a +20 point increase in the air quality index resulted in about 26% more mistakes from the chess players. Even with pristine air, the players still made mistakes, but the mistakes with worse air were bigger and got even worse under time pressure.
PM2.5 pollution used to be really bad in cities (see the famous London Fog or photos of Los Angeles from the 1970s), but regulations have improved the air quality significantly since the turn of the century. Now, the really bad days in the US are mostly due to wildfires, though vehicles and industry remain a constant source. In Berkeley, where I live, most days have air quality around 40, which might explain my lack of progression toward becoming a chess grandmaster!
On bad AQI days, an N95 mask is the cheapest solution, but a more comfortable one is a cheap HEPA filter running. Models are widely available for under $100 that can keep a small-to-medium room clear even on the smokiest days. And if you run it on regular days too, better air quality is always better.
Finally, temperature matters a lot. It won’t come as a huge surprise that the optimal range is 71-72 degrees Fahrenheit. Performance on mental challenges decreases by about 1% for every degree above 77 or below 68 degrees. And it’s not just at the office - students in dorms without air conditioning saw a 13% decrease in reaction times and in cognitive performance on hot days.
Interestingly, there is a difference between men and women, so the 1960s strategy of “make it cold enough for a guy in a suit to be comfortable” worked well then and less-well now. Women tend to see their performance decline more slowly when it gets hotter, and men tend to see their performance decline more slowly in cold temperatures than in hot. Not great news for me given the temperature records we’ve been setting this year.
Regardless, everyone does best at 71-72 degrees, so set the thermostat accordingly!
Matching the space to the project
Beyond being able to breathe, which is universal, the optimal environment generally depends on what kinds of tasks and projects you’re currently working on. One caveat for this section: virtually all studies in this direction are pretty small, and it’s mostly impossible to blind participants. After all, if you’re studying the impact of ceiling heights, people can just look up!
That said, there seem to be a couple of levers where matching the type of environment to the task at hand can make a difference.
The first is noise levels. If you’ve ever struggled to work on a task in a silent room, only to find flow coming easily in a coffee shop, you’re not alone. The kind of noise you get in a 70db cafe murmur is known as disfluent noise, and it helps your brain with abstract thinking. It’s exactly the kind of boost you need when you’re stuck and can’t get started on something.
When you’re not stuck, though, quiet rooms or white noise are usually the best for concentration. One study showed that a 60dB air conditioner was less distracting than a very quiet (45 dB) conversation. The reason is because our brains cue in on words, which interrupt our working memory. That’s why listening to music with lyrics can be more distracting than listening to instrumental music. It’s also why open plan offices tend to result in fewer conversations rather than more – people don’t want to distract the people next to them with conversation. And no matter where you’re working, if there’s any noise louder than 85 dB (a typical hair dryer), you’re not going to be able to get anything done. So grab those noise-canceling headphones.
As far as architecture goes, you want nearly opposite room conditions for creative work vs. analytical, detailed work. If you’re writing or composing, you want high ceilings with dim blue-tinted light and lots of space. If you’re reviewing tax returns, you want low ceilings, bright red-tinted light, and confines that are just short of making you claustrophobic. Furniture design actually makes a small difference here too - angular furniture sharpens your focus and curved furniture makes you slightly more creative.
When in doubt, if you feel like your environment isn’t working for you, change it. Go work at a table outside (weather permitting), or I’ve even been guilty of reviewing a document in my car (which happened to have red accent lights!)
Fixes that fit on a desk
Most of us who don’t work from home every day don’t have the freedom (or the responsibility) to choose the office space we work in. The office is what the office is.
But there are a few small, low-cost interventions you can make at your desk, even when “raise the ceilings” isn’t really an option.
First, getting a cheap USB desk fan can be a game changer. In the confines of a cubicle, CO2 levels can easily reach 1,200ppm. Setting a fan to disperse that plume will reduce the levels to around 950ppm, while also providing white noise and the option to make yourself cooler in case it gets hot.
Those of us who’ve spent time in open offices know how important a good pair of headphones can be. When you’re trying to focus, pink noise is the best for covering conversation or when there are sharp-sounding intrusions rather than a constant background drone. If you’re going to need to wear headphones with white noise for a long period of time, though, brown noise typically has less hiss in it, which makes you get less fatigued listening to it.
Dragging a little nature into your desk can help too. Participants in a study who added a plant to their desk reported less fatigue and thirst. Unless you plant a full-on jungle, though, the impact on humidity and CO2 from a humble desk plant is too small to be meaningful, so the value comes from the psychology of seeing something green and natural. That helps explain why a 40-second picture break, looking at a forest scene, can help boost brain waves and restore energy levels.
Finally, if you’ve teased your buddy who’s a little too into aromatherapy, you might owe them an apology. Ancient Greeks used the smell of rosemary to boost their memory, and there’s some, albeit limited, evidence that it works. There’s a little bit stronger evidence that peppermint oil can help boost alertness, so maybe a cup of mint tea is just what you need when the day starts to feel way too long.
Tip of the Week
So you’ve been sitting in the conference room, elbow-to-elbow for the past 70 minutes. Now, it’s time to make the decision that will determine what your team’s priority will be for the next quarter.
Before you make it, open a window.
Let the CO2 levels go back to baseline levels, give your brain a break, and make a better decision. If you don’t have a window in your conference room, at least open the door and let everyone take a bio break while the door is open and the carbon dioxide can come out.
The next time you need to make a decision or work on an important project, keep in mind that your environment is almost as important as how hard you work. So breathe easy out there!
This post is based on Episode 22 of Less Busy Lab, a podcast of our field notes from 20 years running a productivity software company. Subscribe wherever you get your podcasts!