Office air quality affects workers' cognitive function, study shows

WASHINGTON (AFP) — Feeling sluggish at work? Poor ventilation and pollution might play a part. A new study by scientists at Harvard has found that the air quality inside an office can have a significant impact on employees' cognitive function, including response times and ability to focus.

''We have a huge body of research on the exposure to outdoor pollution, but we spend 90 percent of our time indoors,'' Jose Guillermo Cedeno Laurent, a research fellow and lead author of the paper published Thursday in Environmental Research Letters, told AFP.

The limited amount of prior studies on indoor settings had focused on measures like thermal comfort and satisfaction, rather than on cognitive outcomes, he added.

Cedeno Laurent and colleagues designed a study that followed 302 office workers across six countries (China, India, Mexico, Thailand, the United States of America, and the United Kingdom) over a period of a year.

It ended in March 2020 when the Covid-19 pandemic brought global lockdowns.

All participants were aged between 18 and 65, worked at least three days in an office building, and had a permanent workstation within the office.

Their workspaces were fitted with an environmental sensor to monitor real time concentrations of fine particulate matter 2.5 micrometers and smaller, PM2.5, as well as carbon dioxide, temperature, and relative humidity.

The participants were given a custom-designed app on their phones to carry out the cognitive tests. They were prompted to take the tests at prescheduled times or when the sensors detected PM2.5 and CO2 levels that fell below or exceeded certain thresholds.

CO2 concentrations serve as a proxy for ventilation levels. Outside, concentrations are around 400 ppm (parts per million), while 1000 ppm is cited as an upper limit for indoors.

There were two tests. The first required employees to correctly identify the color of displayed words that spelled out another color.

This evaluated cognitive speed and the ability to focus on relevant stimuli when irrelevant stimuli are being presented.

The second test involved basic addition and subtraction with two-digit-long numbers, to assess cognitive speed and working memory.