Posts Tagged ‘Joseph Allen’

Too Much Carbon Dioxide May Cloud Our Thinking

March 8, 2016

The title of this post is the same as the title of an article by Marlene Cimons in the Health Section of the March 1, 2016 Washington Post.  The bottom line is that due to two recent studies, we have something new about which to be concerned, and a reason to be even more concerned about global warming.    Until recently it was thought that carbon dioxide  was harmless except at what was regarded as extremely high levels of 5,000 parts per million (PPM) or more.

In 2012 scientists at the Department of Energy’s Lawrence Berkeley National Laboratory decided to conduct their study after finding two small Hungarian studies suggesting that indoor carbon dioxide was harmful at levels lower than 5,000 ppm.  The study found  significant reductions on six scales to decision-making performance at carbon dioxide levels of 1,000 ppm and large reductions on seven of the scales  (that is one additional scale) at 2,500 ppm.  In other words that even at 1,000 ppm there were some adverse effects on decision making,and 2500 produced dysfunctional performance.

Outdoor concentrations of carbon dioxide in the air are around 400 ppm.  Building operators have tried to keep levels blow 1,000 ppm as an indication of adequate general ventilation, not be cause they were concerned about carbon dioxide itself.  Indoor levels can reach  several thousand ppm with concentrations in classrooms occasionally exceeding 3,000 ppm.

Researchers at Harvard and from SUNY Upstate Medical Center used similar testing methods but monitored performance over a longer period confirming the results from the 2012 study.  These researchers studied the effects of different concentration of air pollutants including carbon dioxide as well as performance under high and low ventilation.  Cognitive scores were 61% higher on days with low concentrations if pollutants, compared with the same participants’ scores when they spent  in a low-ventilation environment with elevated levels of pollutants, and 101% better on days with the most ventilation.

For seven of the nine areas of productive decision-making, the average scores decreased as the level of carbon dioxide grew higher.  Compared with the two days of high ventilation, cognitive function scores were 15% lower on the day with moderate carbon dioxide, about 945 ppm and 50% lower  on the day with carbon dioxide concentrations around 1,400 ppm.

Joseph Allen, an assistant professor of exposure assessment science at the Harvard T. H. Chan School of Public Health suggests that spending money to increase ventilation in office buildings would be very cost-effective for employers by estimating the cost of doubling indoor ventilation rates at $40 per person annually against a productivity gain of $6500 per person per year.

So there is ample justification for improving building environmentally and for being concerned by global warming.

I am curious about the long-term effects of breathing high levels of carbon dioxide.  I am also curious as to whether increased oxygen intake  can improve performance.  Perhaps there is justification for oxygen heavy rooms or for facilities where people can take an extra shot of oxygen.  s