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Cashins & Associates Blog

Is Indoor Air Quality Affecting Your Intelligence?

Posted by Zachary Keefe on Fri, Jan, 15, 2016 @ 14:01 PM


If you think your workplaces is making you dumber, you may be onto something.

In a study published in Environmental Health Perspectives, researcher Joseph G. Allen et al assessed the effect of certain aspects of Indoor Environmental Quality (IEQ) on higher order cognitive function. What they found may make you view your workplace environment in a new light.

The study involved 24 participants working in controlled office environments for a period of six days. During that period, the individuals were exposed to one of the following environments:

  1. Conventional - This environment was designed to emulate the energy-efficient building type common in the 1980s and 1990s. Researchers replicated typical VOC levels found in these types of buildings, which is typically around 500 ppb. Outdoor air ventilation rates were kept at 20 CFM per person, consistent with the current ASHRAE guidelines.

  2. Green - This office space was designed to replicate the lower VOC levels found in newer Green-certified buildings. Again, outdoor air ventilation rates were kept at 20 CFM per person.

  3. Green+ - For this environment, ventilation rates were increased to 40 CFM per person

  4. High Carbon Dioxide - In this space, levels of carbon dioxide were artificially increased to both 945 ppm and 1,400 ppm.

To test the higher order cognitive function of the participants, the researchers utilized the Strategic Management Simulation (SMS) software tool, which is designed to test the higher-order decision making of management-level employees. Cognitive function was tested daily at 3:00 pm.

The results were rather impressive. On average, cognitive function was found to be 61% higher in Green (low VOC) than in Conventional (high VOC). Results were found to be 110% higher on the two Green+ days (high outdoor ventilation rate) than the conventional building day.

Perhaps more intriguing was the effect of carbon dioxide on higher cognitive function. Traditionally, carbon dioxide has not been seen as a contaminant in and of itself per se, but as an indicator of overall ventilation effectiveness. In this and similar studies, however, this traditional assumption is challenged. Researchers found that cognitive function decreased markedly with each increase in CO2 levels. Scores were found to be 15% lower for the moderate day (945 ppm) and 50% lower on the day with concentrations around 1,400 ppm when compared to the two Green+ days.

Another way to look at the results is in the following breakdown:

  • a 400 ppm increase in C02 meant a 21% decrease in cognitive function
  • a 20 CFM per person increase in outdoor air ventilation meant an 18% increase
  • an increase in TVOCs by 500 ug/m3 meant a 13% decrease in cognitive scores

All of this underscores the importance of indoor environmental quality on modern day workers. Further, it shows that the Green Building movement is bettering this environment by offering credits for lowering overall TVOC levels. It also suggests that, rather than simply being an indicator gas, carbon dioxide may have a much greater direct impact on occupants than previously thought.

Currently, the United States Green Building Council does not give credits for exceeding ASHRAE’s recommended outdoor ventilation rates. However, if more studies like this emerge which link higher ventilation rates to dramatically increased cognitive function, this may have to change. Additionally, results like these might lead IAQ professionals to rethink the role of CO2 testing in their routine investigations.

For more information on indoor air quality download our informational paper today! If you have an indoor air quality issue at your commercial business please call or fill out a web inquiry form. One of our experts will respond within 24 - 48 hours. 

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Topics: indoor air quality

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