Possible future impacts of elevated levels of atmospheric CO₂ on human cognitive performance and on the design and operation of ventilation systems in buildings

Abstract

This paper brings together a rapid evidence assessment of impacts of elevated CO 2 concentrations on human cognition with IPCC projections of atmospheric CO 2 concentration by the end of the present century, and an analysis of potential consequences of increased atmospheric CO 2 concentrations for ventilation systems in buildings and other enclosed spaces. Whilst only limited research has been done on the effect of CO 2 on cognition (as opposed to air quality in general), half of the studies reviewed indicate that human cognitive performance declines with increasing CO 2 concentrations. Hence, given the likelihood of increasing atmospheric CO 2 concentration by the end of the 21st century, direct impacts of anthropogenic CO 2 emissions on human cognitive performance may be unavoidable. Attempts to minimise these direct impacts are likely to result in significant indirect impacts on the engineering of ventilation systems and associated energy use in all enclosed spaces including buildings and transport systems. Practical application: This paper concerns what may well be one of the most important long-term drivers of the design, management, operation and regulation of ventilation systems over the remainder of the 21st century. It will be relevant to professionals, particularly at senior levels in the building industry.

Hypothesis: Potentially Systemic Impacts of Elevated CO2 on the Human Proteome and Health

“…Brain performance is believed to be particularly sensitive to shifting pH ( 54 ). This is consistent with extensive epidemiological evidence that humans spending significant times in environments with elevated p CO 2 suffer from attention deficit and learning disorders [( 26 , 55 ); e.g., Figure 1 ]. Moreover, the aggregation of proteins into insoluble amyloid fibrils, which could be achieved with a reduction in pH, is the hallmark of many highly debilitating brain pathologies such as Alzheimer's or Parkinson's disease.…”

“…Ignoring the hypothesis formulated here may result in shifting health baselines of human populations that are continuously exposed to rising CO 2 in the environment as humans adhere to increasingly crowded indoor, urban lifestyles. The suite of health syndromes associated with chronic exposure to elevated CO 2 in indoor environments is not unavoidable ( 55 ), as solutions may be relatively simple. For instance, efficient ventilation systems in intelligent buildings combined with carbon capture technologies may be deployed in buildings to ensure CO 2 levels indoors are conducive to healthier lifestyles ( 63 , 64 ).…”

Human responses to high levels of carbon dioxide and air temperature

“…A large number of studies have shown that indoor air temperature, humidity, and elevated CO 2 level (caused by a low ventilation rate) have a significant impact on occupant satisfaction, 9 health, [10][11][12] and cognitive performance. [13][14][15] When the CO 2 level exceeds 1000 ppm, headaches, eye irritation, and upper respiratory symptoms are increasingly reported, [16][17][18] and these symptoms have been significantly associated with indoor CO 2 levels.…”

Carbon Dioxide Footprint and Its Impacts: A Case of Academic Buildings

“…CO 2 is a consequence of the human metabolism and is kept to clarify buildings adequately. Fresh air needs to be provided to the end user of the buildings [2][3][4]. A higher level of CO 2 concentration may affect human consciousness, causing headaches, fatigue, nausea, dizziness, and vomiting.…”