A recent study conducted by Global Workplace Analytics estimates around 4.3 million people work remote at least half the time, and as a result the traditional office setting is quickly slipping into the past and being replaced with alternative workspaces—particularly with the readily-available coffee shop.

The coffee shop ambiance has become a paradigm for productivity—between its aroma, endless supply of caffeine, and even noise levels that have been proven to boost creativity, it’s no surprise that many of us will default to our local coffee shop as the perfect place to punch through a daunting project or to-do list. While it’s true that ambiance can have an impact on our work ethic, does a work session at the local coffee shop have any effect on our health?

Those relying on coffee shops as their primary or regular go-to workspace can easily clock in multi-hour days working in these communal spaces, so it’s important that coffee shops are designed with human health in mind—especially when it comes to their indoor air quality.

Indoor air can have a profound impact on our health, affecting allergies, asthma, skin health, focus and brain function, and more. Indoor air can be 5x more polluted than outdoors, and exposure to unhealthy indoor air has even been known to cause flu-like symptoms—which can create work conditions that are less than ideal. Air quality is quickly becoming a top priority for corporate offices, universities, apartment complexes, and more—there isn’t any reason why it shouldn’t be a concern for high-traffic coffee shops as well.

Is working at a coffee shop helping or harming your health and productivity? We decided to see for ourselves by putting two major coffee chains to the test:

The Experiment:

Downtown San Francisco is overflowing with both local and chain coffee shops that host many freelancers, remote workers, and meetings throughout the day. For this experiment we decided to test the South of Market locations of two well-known chains; “Coffee Shop A” is part of a larger chain of about 27,000 shops worldwide, and “Coffee Shop B” is part of a well-known US chain with about 200 shops nationwide.

Both shops were located one block apart to keep any outdoor factors (such as weather) constant, and both shops were relatively the same size in square footage. Coffee Shop A and Coffee Shop B were clearly designed to accommodate for working clientele--along with groups of tables and chairs, both shops included larger workspace tables that provided outlets.

We decided to test the air quality in both coffee shops from 6am to 6pm on a Tuesday in August. We worked throughout the day at each location at the same time. Each team member placed Awair Omni, an enterprise-grade indoor air quality monitor, next to their work station to continuously track the temperature, humidity, airborne chemicals (VOCs), fine dust (PM2.5) and carbon dioxide levels throughout the day.

The Results:

Here’s what we--and over hundreds of other coffee-shop goers--were breathing that day:

Coffee Shop Carbon Dioxide

One of the best ways to understand if an environment is getting enough fresh air is to take a look at its carbon dioxide levels.

Carbon dioxide is by no means a toxic gas—it’s a very natural ingredient in the air we breathe. Humans play a role in adding carbon dioxide to our air, since we exhale about 2.3 pounds of carbon dioxide every day. While we may not notice carbon dioxide in our air the same way we would for other gases, it’s very important to keep it in moderation.

If there’s an above-average amount of carbon dioxide in the air you’re breathing, you’ll begin to notice some side effects, including decreased productivity, headaches, difficulty making decisions, and drowsiness–all of which can drastically slow down a working session.

Taking a look at the hourly carbon dioxide levels in both coffee shops throughout the day:

Both coffee shops consistently experience levels of carbon dioxide that are higher than the recommended level of 600 ppm--working in these conditions even in the short-term have been known to cause the side effects mentioned above, seemingly having the inverse effect of the productive atmosphere a coffee shop typically tries to achieve.

Why does Coffee Shop A have levels of CO2 that are almost double that of Coffee Shop B at times? The answer lies in the layout of both shops.

A key difference between the two shops is their number of entrances and the location of these entrances. Coffee Shop A included one main entrance at the front of the shop. While this entrance conveniently deposits visitors at the barista bar line, a series of bookshelves in the center of the shop (presumably used to section off the shop and guide the line) obstructs the entrance after a few short steps.

The coffee shop is located on a building ground floor, so its windows are sealed shut--which means the only option for fresh air to enter the crowded shop is via the single entrance. Since indoor air can be 5x’s more polluted than outdoors, a steady supply of fresh air from outside is the best method for keeping indoor air at a healthy level. A clear path for fresh air to flow throughout the space is equally important as the source, and with a large set of bookcases obstructing a potential air flow path from the single-door source, it’s easy to see how stale, carbon dioxide-filled air can linger in this coffee shop.

The lack of fresh air and limited air flow in Coffee Shop A is illustrated by the consistently high levels of carbon dioxide and also by the shape of the graph: our team member noted that the graph’s sharp increases correlate perfectly with busy times in the shop--the more people breathing in a crowded space, the higher the carbon dioxide.

Coffee Shop B had one small difference in its layout design that turned out to make a significant impact on its air quality:

The two entrances located on perpendicular walls were both frequently used and allowed for a much more steady flow of air compared to Coffee Shop A. The location of the two doors on either side of the coffee shop also helped push out stale air while pulling in fresh air, creating a steady air flow.

Although Coffee Shop B consistently boasts lower levels of CO2 throughout the day compared to Coffee Shop A, the additional door proved to not be enough to keep carbon dioxide levels within a healthy range--the lowest levels of CO2 recorded for the day were first thing in the morning at about 630 parts per million (ppm). While it can be proven that including the second door did make a difference in air flow, the relatively small size of the coffee shop and high levels of foot traffic throughout the day means steps need to be taken to guarantee those working in the coffee shop have better access to fresh, productivity-inducing air.

Coffee Shop Chemicals

The type of chemicals we were concerned with testing are called VOC’s: volatile organic compounds.

VOCs are notorious for triggering a list of irritating health effects, including flu-like symptoms, fatigue, headaches, and confusion. Workplaces that pride themselves on employee well-being will proactively test for their VOC levels to ensure that they are providing their workforce with a healthy and productive environment.

VOC’s are much more common in the air we breathe than we realize–to the point where they are almost impossible to avoid–because they can be found in most common items, including paint, sealants, and cleaning supplies. It’s very possible that VOCs are lurking in coffee shops, off-gassing from tables, upholstered chairs, painted walls or flooring, freshly-cleaned countertops, and any products used to make coffee itself.

These two particular coffee shops added data to our concerns:

Coffee Shop B’s chemical levels were consistently high throughout the day, to the point where they never reached the recommended “safe” levels around 100 ppb--in fact, they were often in the “unhealthy” to “very unhealthy” range throughout the day.

While Coffee Shop B’s carbon dioxide levels proved the shop has a healthy amount airflow, its high chemical levels seem to tell a separate story. How can this be the case? This particular coffee shop is new to the neighborhood and was opened inside a new building a few months before our experiment took place. The new building materials, paint, sealants, and even furniture in the shop are still clearly emitting VOCs into the shop's air in a process called off-gassing--and off-gassing can take place for months after a wall is freshly painted or new furniture is introduced into a room. What’s worse, each new item, coat of paint, and sealant could be emitting a separate type of VOC, essentially creating a swirling cocktail of chemicals in this coffee shop at levels that are too high to eliminate with a few open doors.

Coffee Shop A, on the other hand, was able to achieve healthy levels of chemicals at certain points throughout the workday, which may mean that this “older” coffee shop has less of an off-gassing problem than the newer Coffee Shop B. Unfortunately this isn’t the cure-all for completely eliminating VOCs, and our team member noted that every time the coffee shop became crowded, the chemical levels quickly climbed to an “unhealthy” amount--most likely another negative side effect of the lack of fresh air and air flow in Coffee Shop A.

Coffee Shop Temperatures

Temperature has a much more profound impact on us than we may realize—especially when it comes to productivity.

A series of studies have proven that we are unable to concentrate and fully engage with our work if the temperature around us is not within a certain range; if you want to reach a peak level of productivity, you should work in an environment that stays between 68℉ and 76℉.

Temperature can be subjective--some of us may prefer to feel colder than others for certain activities--one of the main takeaways for temperature is that it should stay at a regulated level: if you are in a room where the temperature continues to change, you’ll find that your body will work over-time trying to regulate and compensate for the changes, which can easily distract from your task at hand.

The difference in hourly temperature between the two shops tells an interesting story:

One major takeaway from these two graphs is that one coffee shop has an air conditioning/HVAC system while the other does not. Can you guess which?

Coffee Shop A’s graph is an almost perfect example of how a HVAC system affects air quality. Most HVAC systems are centrally controlled and account for the entire building--as opposed to the coffee shop, which can be considered just one “room”--and is constantly working to keep the building at a set temperature. To achieve this set temperature, the HVAC system will continuously add hot or cold air to the building, which is why Coffee Shop A’s graph is filled with constant dips and spikes in temperature--the midpoint of these dips and spikes is usually the actual temperature the HVAC system is trying to achieve.

Coffee Shop A’s dramatic and jagged line can actually be an ideal environment to work in--the HVAC system keeps the indoor temperature at a very steady range, varying only by a point of a degree at times. The only pitfall of working in this environment is if the HVAC system is trying to achieve a temperature that is too hot or cold to be conducive to productivity.

Alternatively, Coffee Shop B seems to forego an HVAC system, and it’s indoor temperature mimics San Francisco’s outdoor weather throughout that day. Not specifically regulating indoor temperature can quickly lead to problems, as shown by the graph: the indoor temperature jumps almost 10 degrees throughout the course of the day, which can be a noticeable amount for anyone trying to spend an entire productive work day in this space.

Coffee Shop Humidity

Humidity is a measurement of the amount of water in the air we breathe–typically in the form of water vapor.

When we measure humidity, it’s typically in the form of “relative humidity,” which is the proportion of the amount of water that air can hold at a given temperature. Humidity plays an important role in your overall comfort, and too high or low humidity can cause health problems.

High humidity indoors can be very uncomfortable–causing the air to feel stale and warmer than it truly is. Humidity over 50% can also contribute to mold and mildew growth, affecting allergies and other health hazards. If indoor humidity is below 40%, you’ll start to experience eye, nose, skin, and throat irritation. If you wear contact lenses, they can become irritated as well. Keeping a delicate balance of humidity between 40% and 50% can help improve productivity and focus.

Neither coffee shop was able to achieve a healthy level of humidity:

There’s an obvious trend between Coffee Shop A’s temperature and humidity graphs, and this is no coincidence: a side effect of  HVAC systems is that a space’s humidity levels will be affected along with its temperature, and it will have a perfectly inverse relationship--when the HVAC forces a drop in temperature, the humidity will rise.

Unfortunately, Coffee Shop A’s HVAC was not set to account for humidity, which caused the shop’s indoor humidity to be forced to unhealthy levels.

On the other side, Coffee Shop B’s choice to not use an HVAC system also affected its indoor humidity. Since it wasn’t actively mitigating taking control of its indoor humidity, Coffee Shop B’s humidity levels stayed consistently higher than recommended, and almost perfectly reflected outdoor humidity levels in San Francisco that day--almost as if those working in the coffee shop may as well have been working outside.

The Takeaway:

Given these results, should you continue to use your local coffee shop as a workplace? Our answer is yes--as long as you can confirm your coffee shop is also working for you.

Before you clock in another productive day at the coffee shop, make sure it’s providing you with the best possible air quality with the following checklist:

1. More than one source of fresh air

Check if your coffee shop has two or more doors or a few open windows to make sure you’re getting enough fresh air throughout the day--this will help reduce your exposure to chemicals and excess carbon dioxide.

2. A working HVAC system

Make sure your coffee shop has a solution for regulating temperature and humidity--otherwise, you may be working in conditions that can slow your productivity.

3. An air quality monitor

Workplaces, campuses, apartment buildings and more are committed to providing clean, healthy air for their employees, students, and customers--why shouldn’t your coffee shop provide you with the same?

Want to make your business a healthier place for patrons to congregate? Awair Omni was designed to help businesses like yours understand and control their indoor air quality.