The best way to tackle a tough task at work may be to crack a window and breathe deep.

Compared with inhaling fresh air, gulping down the stale air found in conventional office buildings can stifle cognitive function by half, researchers report in Environmental Health Perspectives. The finding suggests that improving the performance, productivity, and health of many office workers could be done with just a fresh breeze.

“The results are striking,” lead researcher Joseph Allen, director of the Healthy Buildings program at Harvard, told Ars. Researchers knew that air quality would likely affect cognitive function and work performance, but earlier studies included few people and reported subjective data. We didn’t expect to see that high quality air could double cognitive scores, Allen said.

Allen and his colleagues conducted a double-blind study of 24 trained professionals, including architects, designers, and engineers. For two consecutive weeks, the participants spent Tuesday through Thursday working in what looked like a typical office space, complete with cubicles and dull office furniture. (The mid-week design eliminated the concern about known mental effects of Mondays and Fridays.)

The office space was anything but typical, however; it was actually in the Willis H. Carrier Total Indoor Environmental Quality (TIEQ) Lab, part of Syracuse University, which has a LEED® platinum-level certification. As a green building, it’s designed to have high air quality, achieved by guidelines for ventilation, filtration, and materials. This results in lower levels of carbon dioxide and volatile organic compounds (VOCs), which would normally waft from a variety of office products such as building materials, vinyl mats, adhesive tapes, and dry erase markers. But as a laboratory, it also has the ability to vary all of those conditions as well as many others.

Allen and his colleagues used the lab to simulate good and bad office air—the latter of which is found is conventional office buildings. Those buildings are designed for energy efficiency, Allen explained. They’re good at keeping in conditioned air to save energy but sacrifice air exchange with the outdoors. This leads to higher levels of CO 2 and VOCs.

For each day of the 6-day study, the researchers tweaked air quality, CO 2 and VOC levels, and the amount of ventilation. To alter VOCs levels, the researchers injected scentless compounds into the office space through diffusers hidden in the floors.

The scenarios included the air quality of: a conventional office, a green office (low VOCs), a green office with enhanced ventilation for lower CO 2 (green+), a green+ office with moderate CO 2 levels added, and a green+ office with high CO 2 levels added. For the sixth day, the researchers repeated the green+ day as an internal control to make sure they got the same results.

And at 3pm each day, the 24 participants, who had no idea what kind of air they had breathed all day, took a cognitive function test. That test was administered by technicians who also had no idea what kind of air conditions filled the office.

The test looked at nine types of mental function "domains," including strategy, crisis response, and information usage. The idea is to assess how the participants might handle real world work challenges, Allen said.

He and colleagues analyzed the differences within each individual participant's scores across the six days. On average, the workers’ cognitive functions doubled on green+ days compared to those on the conventional office air day. Scores were also 61 percent higher on the green day than on the conventional day. All three factors (ventilation plus VOCs and CO 2 levels) could contribute to score changes, Allen said.

The finding that CO 2 levels can also affect thinking is “particularly important,” William Fisk, leader of the indoor environment group at the Lawrence Berkeley National Laboratory, told Ars. “For decades, nearly everyone had thought that carbon dioxide at the concentrations encountered in buildings had no effects on people,” he said.

Whether the cognitive effects would remain day after day in the same quality air, or lead to lifelong health problems are still open questions, Allen said. In his next study, he plans to look at those longer-term issues.

Environmental Health Perspectives, 2015. DOI: 10.1289/ehp.1510037 (About DOIs).