Good Indoor Air Quality Improves Productivity


Harvard: Improved Indoor Air Quality Doubles Executive Decision-Making Scores

In a study conducted by researchers at Harvard and Syracuse Universities and published in the October 26 issue of Environmental Health Perspectives, researchers found that managers exposed to lower levels of carbon dioxide (CO2) and volatile organic compounds (VOC’s) in a highly controlled office setting scored 100% higher in tests measuring management-level cognitive reasoning skills. Atmospheric CO2 is found in the outdoor air in concentrations of approximately 400 ppm, but in occupied spaces climbs to higher levels directly as a result of the air exhaled by occupants. VOC’s are emitted by carpets, engineered wood furnishings and flooring, paints and finishes, cleaning products, and personal care products. Both CO2 and VOC’s are diluted by increasing outdoor air ventilation.

Researchers who conducted the double-blinded study, which has been widely praised by other notable researchers for the validity of its design characteristics, administered a battery of well-vetted standard cognitive tests to office professionals (architects, designers, programmers, engineers, creative marketing professionals, and managers) exposed to different levels of CO2 and VOC’s over a period of 6 days. They found that workers in Green+ buildings with average CO2 levels of 586 ppm and average VOC levels of 41 ug/m3 scored 100% higher on the management decision-making tests than workers in conventional/typical commercial office spaces with average CO2 levels of 945 ppm and average VOC levels of 586 ug/m3.


These results have tremendous implications within the business, healthcare, legal and other communities where mental acuity and excellent decision-making are critical to success on a day-to-day basis. Joseph Allen, Harvard professor and lead author of the study, states that “these results suggest that even modest improvements to indoor environmental quality may have a profound impact on the decision-making performance of workers” (Harvard School of Public Health press release). But it should be recognized that the enhanced CO2 levels in the study were achieved by increasing the mix of 50% outdoor air and 50% recirculated air (20 CFM per occupant) through the HVAC system in the conventional office model to 100% outdoor air (40 CFM per occupant) in the Green+ model. This enhancement comes at the cost of significantly increased energy usage, and pushback can be expected from building owners who will argue that they are in compliance with NYC Building Code requirements of 20 CFM per occupant (calculates to 945 ppm of CO2) of outdoor air, which is already more stringent than the ASHRAE and LEED standards which are based on 15 CFM of outdoor air (calculates to 1100 ppm CO2 or 700 ppm above outdoor levels). Unfortunately, the Harvard-Syracuse study demonstrates that these levels of ventilation significantly impede decision-making ability. Therefore, top management has a cost-benefit analysis to weigh by putting a value on the benefits of improved decision-making and comparing this value to the cost of increased energy usage for which building owners will expect to be compensated.


At Microecologies, our team of environmental professionals has been evaluating CO2 and VOC levels and other parameters critical to indoor air quality in commercial spaces and providing solution options to management for the past 22 years, and we often find CO2 and VOC levels in prestigious New York commercial buildings that are even higher than the levels cited in the study for conventional offices. The scope of our indoor environmental evaluation for commercial spaces includes evaluating CO2 and total VOC levels using state of the art direct-reading instruments, enabling us to evaluate levels throughout the facility in a time and cost-efficient manner and to rapidly track improvements resulting from increased outdoor air ventilation and other engineering and administrative changes. It should be pointed out that in offices with lower levels of occupant density than in the study, the target ventilation rate of 40 CFM per occupant and the target CO2 level of 545 ppm may be achievable without increasing the outdoor air ventilation rate to the 100% level.


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