According to new research supported primarily by Carrier Global Corporation and led by the Harvard T.H. Chan School of Public Health, the air quality within an office can have a significant impact on employees’ cognitive function while also affecting their productivity.

While it is well known that air pollutants such as fine particulate matter (PM2.5) can penetrate indoor environments, few studies up to this point have focused on how indoor exposures to PM2.5 and outdoor air ventilation rates affect cognition. Jose Guillermo Cedeño-Laurent, a research fellow in the Department of Environmental Health and lead author of the study, noted that this is a particularly important area of research given the high percentage of time people spend indoors, especially office workers.

The study (also known as the COGfx Study 3: Global Buildings) featured 300 office workers in cities across China, India, Mexico, Thailand, the United Kingdom, and the United States and is the latest in the COGfx study series examining the impact of indoor air quality on how people think and feel. In it, researchers found that increased concentrations of PM2.5 and lower ventilation rates (measured using carbon dioxide (CO2) levels as a proxy) correspond with slower response times and reduced accuracy on a series of cognitive tests.

“Our study adds to the emerging evidence that air pollution has an impact on our brain. The findings show that increases in PM2.5 levels were associated with acute reductions in cognitive function. It’s the first time we’ve seen these short-term effects among younger adults,” said Cedeño Laurent.

“The study also confirmed how low ventilation rates negatively impact cognitive function. Overall, the study suggests that poor indoor air quality affects health and productivity significantly more than we previously understood.”

Understanding the Full Impact of Air Quality on Cognitive Functions

Each participant’s workspace was outfitted with an environmental sensor that monitored in real-time concentrations of PM2.5 and CO2, as well as temperature and relative humidity. Additionally, each participant had a custom-designed app on their phones through which cognitive tests and surveys could be administered.

Two types of tests were administered: One test required employees to correctly identify the color of displayed words and was used to evaluate cognitive speed and inhibitory control—the ability to focus on relevant stimuli when irrelevant stimuli are also present. The second test consisted of basic arithmetic questions and was used to assess cognitive speed and working memory.

The study found that response times on the color-based test were slower as PM2.5 and CO2 levels increased with accuracy also being affected. For the arithmetic-based test, the study found that increases in CO2 but not PM2.5 were associated with slower response times. As concentrations of both pollutants increased, however, participants completed fewer questions correctly in the allotted test time.

“The world is rightly focused on COVID-19, and strategies like better ventilation and filtration are key to slowing infectious disease transmission indoors,” said Joseph Allen, associate professor of exposure assessment of science and senior author on the study. “Our research consistently finds that the value proposition of these strategies extends to cognitive function and productivity of workers, making healthy buildings foundational to public health and business strategy moving forward.”

Following the COGfx Study

This latest research builds on previous COGfx studies that demonstrated better thinking and better health can be found inside healthier buildings. The first study found cognitive function test scores doubled when study participants were in simulated green building environments with enhanced ventilation as opposed to conventional building environments. The COGfx Study 2 examined real-world building environments in the U.S. and showed that employees in green-certified buildings showed 26% higher cognitive function test scores and 30% fewer sick building symptoms versus buildings that were not green-certified.

Full reports for all studies are available at www.theCOGfxStudy.com, and people can follow the discussion on Twitter using the hashtag #TheCOGfxStudy.

Update: Article was updated from its original to more accurately convey Carrier’s support in the study while also providing additional resources regarding the COGfx series.