Ventilation Rate Success Story

We're just about to finish another semester of ENVR 119C - High Performance Buildings for Occupant Wellness at the Harvard Extension School. The class focuses on how the built environment impacts occupant wellbeing. Tomorrow (4/26/2018) we'll have Piers MacNaughton, ScD, Associate Director of the Healthy Buildings Program in the Center for Health and the Global Environment at the Harvard T.H. Chan School of Public Health. Dr. MacNaughton is one of the authors of the great CogFx studies that have shown a clear link between outdoor air ventilation rates and improved cognitive function in building occupants. Link: http://naturalleader.com/thecogfxstudy/

Dr. MacNaughton's visit reminded me that when I was teaching this class last time, we had Dr. Jack Spengler come in to talk about their paper The Impact Of Green Buildings On Cognitive Function. Students were surprised to learn that even ventilation rates typically considered "safe" may be having a negative impact on cognitive function. Applying these lessons as part of his final project, Bryan Johnson evaluated ventilation rates at his wife's school in Arizona. She teaches 6 classes per day of 35 to 40 students. She had complained to the facilities department and to her husband that the room felt stuffy. Using the class project as an excuse to intervene, Bryan found the outdoor air damper position for the air handler serving her portion of the school was open to 25%. Bryan bought a Netatmo sensor to test CO2 concentrations (among other parameters) and found that CO2 levels were generally above 1,000 ppm during occupied hours, at times going as high as 1,350. He and his wife convinced the school to open the air dampers to 55% and found this brought typical CO2 concentrations to around 650 ppm. They then opened the dampers to 65% and got levels to about 600 ppm. The class has been operating for the past few weeks under these conditions and anecdotal evidence from teacher and students has been positive.

After class, Bryan emailed me with feedback from his wife. She received her year end district standardized final exam scores. Scores for all 6 of this year's classes were up compared to last year by an average of 5%. While the sample size is low and his work may not get published in any peer-reviewed journals, I wanted to share Bryan's results (with his permission) and applaud his effort. He was planning to approach the school with his findings and a series of additional recommendations including improving the lighting quality to more closely approximate natural sunlight thanks in large part to a great lecture from Dr. Lockley of Harvard Medical School's Sleep Institute. Nice work Bryan!