Harvard study links poor office air quality with reduced cognitive function
New research from the Harvard T.H. Chan School of Public Health has found a correlation between air quality in office environments and workers’ cognitive function. The international study found low ventilation rates and increased levels of particulate matter were linked with reduced performance on cognitive tests.
For well over a decade researchers have been investigating the relationship between air pollution and cognitive performance, with the majority of this work focusing on associations between cognitive function and long-term outdoor exposure to fine particulate matter (PM2.5).
The acute effects of indoor air pollution on cognitive function is a particularly understudied area, and this newly published study set out to explore that association. More than 300 subjects were recruited for the year-long study spanning six countries and over 40 office buildings.
Each subject’s workspace was fitted with an environmental sensor package tracking real-time levels of PM2.5, CO2, temperature and relative humidity. When those sensors measured PM2.5 and CO2 levels below or above certain thresholds, a smartphone app would ping the participant and task them with a pair of short cognitive tests.
In general, as PM2.5 and CO2 levels in an indoor environment increased, response times on both cognitive tests slowed down. One particular test, called the Stroop color-word test, is designed to measure attention and inhibitory control. On that test the researchers detected reductions in accuracy as PM2.5 and CO2 levels increased.
“The findings show that increases in PM2.5 levels were associated with acute reductions in cognitive function,” explains lead author Jose Guillermo Cedeño Laurent. “It’s the first time we’ve seen these short-term effects among younger adults. 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.”
Joseph Allen, senior author on the new study, is director of the Harvard Healthy Building Program. For several years his work has centered on how indoor environmental conditions influence a person’s general health.
Allen has long argued for the benefits of improving indoor air quality, and now with a global pandemic bringing attention to issues such as building ventilation, he is seeing huge interest in companies wanting to improve indoor environments.
“The world is rightly focused on COVID-19, and strategies like better ventilation and filtration are key to slowing infectious disease transmission indoors,” says Allen. “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.”
And bad workplace ventilation can affect more than cognitive functions or COVID-19 transmission. This week a team of UK researchers presented new data from a study showing a number of workers in poorly ventilated office spaces suffering from asthma flare-ups.
“We usually think of an office as a safe environment, so it’s possible that when asthma is diagnosed in office workers, occupational causes may be overlooked,” says Christopher Huntley, lead on the new occupational asthma study. “As a result, there has been very little research on this issue. However, we have been diagnosing increasing cases of occupational asthma in patients who work in office environments, as well as detecting clusters of cases in specific offices.”
Allen suggests this growing focus on indoor air quality will hopefully lead to a whole new way of thinking about indoor built environments. And this could be one positive long-term outcome arising out of this devastating global pandemic.
“I think there’s going to be a fundamental rebalancing in terms of how we think about indoor spaces,” Allen said recently in an interview with Science. “I think that people won’t tolerate sick buildings, where you feel tired, your eyes itch, you have a headache, or you’re stuffed into a closet-like office with no windows. That era is over. Rightly so, and good riddance.”
The new study was published in Environmental Research Letters.