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Indoor Air Quality and its Impact on Cognitive Functions

Study results conclude humans function better cognitively in green buildings – specifically those with increased ventilation

A landmark report published in the fall by Harvard’s School of Public Health’s Center for Health and the Global Environment in conjunction with SUNY Update Medical University and Syracuse University observed the impact indoor air quality has on building occupants’ cognitive functioning.

The Study

Researchers performed a double-blind study that evaluated the cognitive performance of 24 participants who experienced conditions in a laboratory setting simulating conditions found in conventional and green buildings, as well as green buildings with increased ventilation.

Study participants spent each day conducting normal work activities in indoor environments that are encountered by individuals in offices buildings around the world every day. At the conclusion of each six-hour workday, subjects completed an hour and a half well-validated, computer-based cognitive assessment test.

Researchers measured cognitive function test results for nine specific functional domains, basic, applied and focused activity levels; task orientation; crisis response; information seeking; information usage; breadth of approach; and strategy.

The Results

The results found that participants’ scores were significantly higher in the areas of crisis response, information use, and strategy. Information usage scores for green and enhanced green environments were 172 and 299 percent higher than in the conventional environment, respectively. For strategy, green and enhanced green scores were 183 and 288 percent higher than the conventional environment. Crisis response scores were 97 percent higher for the green environment and 131 percent higher for the green environment with enhanced ventilation and lower carbon dioxide levels compared to the conventional environment.


Many of the benefits associated with green buildings have long been known — including increased energy efficiency, decreased water use, prominent use of durable and local materials, as well as many other tangible outcomes. And, there has been a general understanding amongst professionals in the green building industry that a healthier indoor environment also translated to increased occupant comfort and wellbeing. This groundbreaking study builds on prior research to quantify the benefits of increased indoor environmental quality on occupants’ cognitive functions.

Building owners, managers, and tenants can use this report, and begin to view an investment in improved indoor environmental quality as an investment in building occupants rather than a facilities investment. The increased levels of the cognitive functions of study participants shows that the payback period for such investments would be negligible as in some cases occupants are performing nearly 300% better in green buildings with increased ventilation than they are in conventional buildings.

In fact, following the study’s release, the principal research team took a closer look at the economic impact of investing in enhanced ventilation measures in a given building. They found that a doubling in cognitive effects scores could be achieved at an average energy cost between fourteen and forty dollars annually per occupant; when energy-efficient technologies are utilized to enhance ventilation rates that projected average energy cost drops to one to eighteen dollars annually per occupant. Researchers estimate that building owners, managers, and renters could see a return on investment of up to $6,500 annually per occupant due to increased cognitive function.

Indoor Air Quality at USGBC HQ

At USGBC, we take this aspect of green building to heart. Our office space in Washington DC was certified Platinum in July 2009 and maintains Platinum status on the LEED Dynamic Plaque. The Plaque is a global building performance monitoring and scoring platform. It generates a score out of 100 and helps projects achieve LEED certification or recertification, and enables building owners and managers to benchmark performance. It includes five categories: energy; water; waste; transportation; and human experience.

Our Facilities Team pays close attention to how our space is performing on the LEED Dynamic Plaque and adjusts building systems accordingly to be sure our facility is operating as it was designed.

The Platinum certified space was awarded 11 out of 17 points under the Indoor Air Quality credit category. Achieving credits meant to facilitate enhanced ventilation such as outdoor air delivery monitoring, increased ventilation and all five credits relating to low-emitting materials. The lobby of our headquarters features a two-story water wall that is not only visually stunning, but also helps to control indoor humidity. Additionally, we have a sustainable purchasing policy in place to reduce the environmental and air quality impacts of the materials acquired for use in the operation and maintenance of our space.

Grant Olear is Green Building Policy Associate at the US Green Building Council