Poor office air pollution impacts productivity
Office air quality may affect employees’ cognitive productivity, according to a new study published by Harvard Chan School of Public Health.
The research team enrolled more than 300 office workers in cities across China, India, Mexico, Thailand, the UK and the US. All participants worked at least three days a week in an office building and each participant’s workspace was fitted with an environmental sensor that monitored real-time concentrations of particulate matter (PM2.5) and CO2.
Study participants were prompted to participate in tests and surveys at prescheduled times. One test required employees to correctly identify the colour of displayed words and was used to evaluate cognitive speed and inhibitory control. The second test consisted of basic arithmetic questions and was used to assess cognitive speed and working memory.
The researchers found that response times on the colour-based test were slower as PM2.5 and CO2 levels increased.
They also found that the accuracy of the colour-based test was affected by pollution levels. For the arithmetic-based test, the study found that increases in CO2 but not PM2.5 were associated with slower response times.
The researchers noted that they observed impaired cognitive function at concentrations of PM2.5 and CO2 that are common in indoor environments.
Jose Guillermo Cedeño Laurent, a research fellow in the Department of Environmental Health and lead author of the study said: ‘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
‘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, associate professor and senior author added: ‘The world is rightly focused on Covid-19, and strategies like better ventilation and filtration are key to slowing infectious disease transmission indoors. 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.’
Photo by Alesia Kazantceva
In the study:
“Controlled environmental exposure studies among office workers have found independent and monotonic effects of same-day CO2 concentrations, as well as effects of CO2 as a subrogate of ventilation rates, on several domains of cognitive function (Satish et al 2012, Allen et al 2016). The mechanism explaining the effects of CO2 as an independent pollutant or as a proxy for ventilation rates on cognitive function at relatively low concentrations (<3000 ppm) is still not fully understood” (page 3, left column second to bottom paragraph)
It’s really important that CO2 in this study is for the most part being ONLY used as a proxy for ventillation rates in the buildings – and – not necessarily as the cause of the cognitive impairment.
In buildings with high CO2, there may also be a significant increase in carbon monoxide (CO) (e.g. above 1 or 2 ppm), it’s possible that NOx levels increase, as we humans breathe we produce CO2, CO, along with assorted VOC’s . In addition office workers may be using office products which produce O3 or out gas VOC’s that also impair cognitive functions.
I’d like to see studies like this one – also collect more information about the other gases which might be increasing in the room, also capture what the background outside air quality is doing at the time.
We really need to include more focus on: “The mechanism explaining the effects of CO2 as an independent pollutant or as a proxy for ventilation rates on cognitive function at relatively low concentrations (<3000 ppm) is still not fully understood”
Data should be collected on TVOC, HCHO, CO, NOx, O3 and gas samples collected.
Time of day, just before or shortly after a meal can make a significant impact also…the testing time and the levels of the gases in the hour or more before testing needs to be captured to better understand is it just the CO2, is CO2 a good proxy, or should some other gas be monitored in buildings.
Interesting but what would be expected. Hopefully temperatures were consistent as thermal comfort could also influence outcomes.