Stale Office Air Is Making You Less Productive

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We found that breathing better air led to significantly better decision-making performance among our participants. We saw higher test scores across nine cognitive function domains when workers were exposed to increased ventilation rates, lower levels of chemicals, and lower carbon dioxide. The results showed the biggest improvements in areas that tested how workers used information to make strategic decisions and how they plan, stay prepared, and strategize during crises. These are exactly the skills needed to be productive in the knowledge economy.

We conducted this as a double-blind study to limit the potential for bias. Just as participants were kept blind to the changing conditions of their workplaces, the scientists who analyzed the cognitive function data were kept blind to the conditions. In addition, we controlled for differences among the participants and measured each individual’s performance against their own baseline. We didn’t care if one person was smarter than another; we were interested in how people compared against themselves. To be sure there was no learning effect (if people scored better after taking the test a few times) and no bias was introduced (if our blinding didn’t work), we repeated one of the exposure conditions (high ventilation, low VOCs, low CO2) on the first and last day, nine days apart. Our results were consistent, indicating that there were no learning effects and that the blinding was effective.

The productivity benefits from doubling the ventilation rates are $6,500 per person per year. This does not include the other potential health benefits, such as reduced sick building syndrome and absenteeism.


Joseph G. Allen


Harvard T.H. Chan School of Public Health

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