Carbon dioxide is a villain in the climate change narrative, but coal plants and factories aren’t the only places that produce it. Humans generate CO2 too, just from breathing. And in certain circumstances, that human-generated CO2 might be enough to impair decision making and overall performance at work. Oddly enough, the problem may be especially prevalent in some energy-efficient buildings.
In a study published in Environmental Health Perspectives, researchers from Lawrence Berkeley National Laboratory and SUNY Upstate Medical University exposed 22 people to various levels of CO2 (600, 1,000, and 2,500 ppm) in an "office-like chamber" for two-and-a-half-hour sessions over the course of a day.
The researchers tested subjects’ decision-making ability with something called the Strategic Management Simulation—a system where participants are given real-world simulation scenarios and asked to respond using a drop-down menu of decisions. Factors measured include flexibility in approach, number of actions taken, opportunistic actions, openness to information, and focus on multiple task demands.
Much to the researchers’ surprise, decision-making abilities started declining significantly at exposure to 1,000 ppm—prior to this, the researchers thought detrimental effects wouldn’t start happening until exposure to at least 10,000 ppm. The exposure that the participants received is fairly common; it has been found in elementary school classrooms in California and Texas (21% of Texas classrooms have a peak CO2 concentration of over 3,000 ppm). Office spaces don’t face the same exposure—one study mentioned in the report of 100 U.S. offices found that only 5% had peak indoor CO2 concentrations of over 1,000 ppm.
But here’s where it gets weird: Energy-efficient buildings may be more at risk of having elevated concentrations of CO2. That’s because poor ventilation is one of the primary causes of elevated CO2 indoors, and lowering ventilation rates can cut down on energy use. As you might imagine, that could cause CO2 levels to rise and decision-making abilities to be affected—even, say the researchers, if air cleaning systems are put in place to combat other pollutants.
The researchers explain in the paper: "It seems unlikely that recommended minimum ventilation rates in future standards would be low enough to cause CO2 levels above 2,500 ppm, a level at which decrements in decision-making performance in our findings were large, but standards with rates that result in 1,500 ppm of indoor CO2 are conceivable."
In other words, future energy-efficiency standards need to take into account indoor CO2 levels just as much as they consider cutting down on energy use—and as a result, outdoor CO2 emissions.