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Washington (AFP)
Do you feel lethargic at work? Poor ventilation and pollution could play a role.
A new study by Harvard scientists has found that the quality of the air inside an office can have a significant impact on the cognitive functions of employees, including response times and the ability to concentrate.
“We have a huge body of research on exposure to outdoor pollution, but we spend 90% of our time indoors,” Jose Guillermo Cedeno Laurent, researcher and lead author of the article, told AFP. published Thursday in Environmental Research Letters.
The limited number of previous studies of indoor environments had focused on measures such as thermal comfort and satisfaction, rather than cognitive outcomes, he added.
Cedeno Laurent and his colleagues designed a study that followed 302 office workers in six countries (China, India, Mexico, Thailand, United States of America and United Kingdom) over a period of one year.
It ended in March 2020 when the Covid-19 pandemic led to global lockdowns.
All participants were between the ages of 18 and 65, worked at least three days in an office building, and had a permanent workstation in the office.
Their workspaces were equipped with an environmental sensor to monitor in real time the concentrations of fine particles of 2.5 micrometers and less, PM2.5, as well as carbon dioxide, temperature and relative humidity.
Participants were given a custom-designed app on their phones to perform cognitive tests, which they were asked to spend at pre-programmed times or when sensors detected levels of PM2.5 and CO2 below or above certain thresholds.
CO2 concentrations serve as a proxy for ventilation levels. Outdoors, concentrations are approximately 400 ppm (parts per million), while 1000 ppm is cited as the upper limit for indoor.
There were two trials. The first required employees to correctly identify the color of displayed words that spelled a different color.
This assessed cognitive speed and the ability to focus on relevant stimuli when irrelevant stimuli are presented.
The second test involved basic addition and subtraction with two-digit numbers, to assess cognitive speed and working memory.
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The results showed that an increase of 10 micrograms per cubic meter of PM2.5 resulted in an approximately one percent reduction in response times to both tests, and a more than one percent reduction in accuracy.
For reference, outdoor PM2.5 levels in the U.S. capital Washington were 13.9 micrograms per cubic meter on Thursday, according to the tracking site IQAir, while they were 42 micrograms per cubic meter in New Delhi.
In terms of CO2, an increase of 500 ppm (parts per million), which is not an unusual level of variation, resulted in a drop of more than one percent in response times and a drop of more than two percent of the accuracy of both tests.
The research comes as the US Congress is on the verge of adopting an infrastructure package, and Cedeno Laurent argues that now is the time to plan for high-performance, high-performance buildings that provide the right amount of ventilation and air conditioning. air filtration.
While previous studies have shown that prolonged exposure to PM2.5 inflames the central nervous system and crosses the blood-brain barrier to cause long-term neurodegenerative disease, this is the first to show short-term effects, he added.
For employees returning to office work in person, there are solutions.
Opening a window is one of them, said Cedeno Laurent. If the quality of the outdoor air is not good, upgrading the building’s filtration systems or adding high-quality portable air purifiers are good ideas.
© 2021 AFP
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