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Indoor Air Quality - Dramatic effect on cognition


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It appears that indoor pollution can have a dramatic effect on cognition. Even if you do control the air quality of your home (do you?), it is quite possible that you may be exposed to poor air quality at your office at work.


Associations of Cognitive Function Scores with Carbon Dioxide, Ventilation, and Volatile Organic Compound Exposures in Office Workers: A Controlled Exposure Study of Green and Conventional Office Environments


Background: The indoor built environment plays a critical role in our overall well-being because of both the amount of time we spend indoors (~90%) and the ability of buildings to positively or negatively influence our health. The advent of sustainable design or green building strategies reinvigorated questions regarding the specific factors in buildings that lead to optimized conditions for health and productivity.

Objective: We simulated indoor environmental quality (IEQ) conditions in “Green” and “Conventional” buildings and evaluated the impacts on an objective measure of human performance: higher-order cognitive function.

Methods: Twenty-four participants spent 6 full work days (0900–1700 hours) in an environmentally controlled office space, blinded to test conditions. On different days, they were exposed to IEQ conditions representative of Conventional [high concentrations of volatile organic compounds (VOCs)] and Green (low concentrations of VOCs) office buildings in the United States. Additional conditions simulated a Green building with a high outdoor air ventilation rate (labeled Green+) and artificially elevated carbon dioxide (CO2) levels independent of ventilation.

Results: On average, cognitive scores were 61% higher on the Green building day and 101% higher on the two Green+ building days than on the Conventional building day (p < 0.0001). VOCs and CO2 were independently associated with cognitive scores.

Conclusions: Cognitive function scores were significantly better under Green+ building conditions than in the Conventional building conditions for all nine functional domains. These findings have wide-ranging implications because this study was designed to reflect conditions that are commonly encountered every day in many indoor environments.

What is particularly interesting, is how little CO2 it takes to have a dramatic effect on cognition - here is a different study:


Is CO2 an Indoor Pollutant? Direct Effects of Low-to-Moderate CO2Concentrations on Human Decision-Making Performance


Background: Associations of higher indoor carbon dioxide (CO2) concentrations with impaired work performance, increased health symptoms, and poorer perceived air quality have been attributed to correlation of indoor CO2 with concentrations of other indoor air pollutants that are also influenced by rates of outdoor-air ventilation.

Objectives: We assessed direct effects of increased CO2, within the range of indoor concentrations, on decision making.

Methods: Twenty-two participants were exposed to CO2 at 600, 1,000, and 2,500 ppm in an office-like chamber, in six groups. Each group was exposed to these conditions in three 2.5-hr sessions, all on 1 day, with exposure order balanced across groups. At 600 ppm, CO2 came from outdoor air and participants’ respiration. Higher concentrations were achieved by injecting ultrapure CO2. Ventilation rate and temperature were constant. Under each condition, participants completed a computer-based test of decision-making performance as well as questionnaires on health symptoms and perceived air quality. Participants and the person administering the decision-making test were blinded to CO2 level. Data were analyzed with analysis of variance models.

Results: Relative to 600 ppm, at 1,000 ppm CO2, moderate and statistically significant decrements occurred in six of nine scales of decision-making performance. At 2,500 ppm, large and statistically significant reductions occurred in seven scales of decision-making performance (raw score ratios, 0.06–0.56), but performance on the focused activity scale increased.

Conclusions: Direct adverse effects of CO2 on human performance may be economically important and may limit energy-saving reductions in outdoor air ventilation per person in buildings. Confirmation of these findings is needed.

Note, that this study asking for more confirmation, has in fact seen confirmation in a later study (the first one I posted here) - at which point one must ask, given how little excess CO2 it takes to affect cognitive function, what of the trend of general CO2 elevation due to climate change? Indoor pollution is of course composed of other substances, but CO2 itself is already responsible for massive cognitive effect - assuming that in winter-proofing or weather-proofing your home you have avoided all dangers of trapping pollutants and CO2, it does little good if the air outside is equally bad due to climate change:


Health effects of increase in concentration of carbon dioxide in the atmosphere


Now, of course, CO2 is not just damaging to cognition, but may even affect health in ways we don't ordinarily think of, like, speculatively, perhaps weight gain:
Bottom line here is that while we are all aware of outdoor pollution due to particulates, and even indoor pollution due to volatile gasses, perhaps we are not paying enough attention to potentially problematic low levels of excess CO2. It's very easy to have excess CO2 indoors, just from weather-proofing one's home, of special concern in wintery locations, but even if you live in a warmer climate, opening the window might not solve our problems even if we banned all cars and BBQ's etc. - climate change might do us in. And how are we supposed to solve much more complex problems of the future while being dumbed down by excess CO2?
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