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Drivers of Higher Cognitive Function Scores

The COGfx Buildingomics Study found higher cognitive function scores, fewer health symptoms and better perception of the indoor environment in high-performing, green-certified buildings compared to similarly high-performing buildings that were not green-certified.

All of the buildings studied had similar air quality – including higher ventilation levels, low CO2 concentrations and low volatile organic compound (VOC) concentrations.

However, in this study, thermal comfort and lighting differed between the two types of buildings. Green-certified buildings were generally less humid than the non-certified buildings. As a result, more participants in these buildings were within the thermal comfort zone defined by ASHRAE. Participants within the ASHRAE thermal comfort zone performed 5 percent higher on cognitive simulations than those outside of the thermal comfort zone.

With regard to lighting, better lighting was associated with better sleep. Researchers noted 6.4 percent higher sleep quality scores in high-performing, green-certified buildings versus high-performing, non-certified buildings. A sleep score from the previous night’s sleep that was 25 percent higher was associated with a cognitive function score that was higher by 2.8 percent.

On average, participants in green-certified buildings saw 26 percent higher cognitive function scores than those in non-certified, high-performing buildings. Higher scores were identified in critical areas such as crisis response and strategy.

  • The greatest cognitive function differences were seen in the areas of crisis response (73 percent higher in green-certified, high-performing buildings); applied activity level – the ability to gear decision-making toward overall goals (44 percent); focused activity level – the capacity to pay attention to situations at hand (38 percent); and strategy (31 percent).
  • Sleep quality scores were 6.4 percent higher for participants in green-certified buildings, suggesting building impact on sleep quality.
  • Finally, participants reported better environmental perceptions and 30 percent fewer sick building symptoms in high-performing, green-certified buildings vs. high-performing, non-certified buildings.

Drivers of Higher Cognitive Function Scores

High-Performing1, Non-certified

Indoor Environment

High-Performing, Green-certified2

Indoor Environment

46%

Relative Humidity

163

LUX

Less Light

38%

Relative Humidity

374

LUX

More Light

Attributes of Both

Indoor Environmental quality parameters

Low Carbon Dioxide:

Less than 950 parts per million

Low Volatile Organic Compounds:

Less than 250 µg/m3

High Ventila­tion Rates

Greater than 20 cubit feet per minute per person of outdoor air

Greater than 80% of participants were in the

Thermal Comfort Zone3

Higher Cognitive Function Scores

In High-performing, green-certified Buildings

31%

Strategy

38%

Focused Activity Level

44%

Applied Activity Level

73%

Crisis Response

Indoor Environmental Quality

There are a variety of IEQ credits available through green building certification organizations that can help achieve improved indoor environments. Examples include:

Reducing Volatile Organic Compound-emitting materials

Providing Daylight / Views and Controll­ability of lighting systems

Achieving Thermal Comfort through design and verification