Cognitive performance

The data from published studies were used to build relationships between learning outcomes and air quality in classrooms. Psychological tests measuring cognitive abilities and skills, school tasks including mathematical and language-based tasks, ratings schemes and tests used to assess progress in learning including end-of-year grades and exam scores were considered to represent learning outcomes. Indoor air quality was characterized by concentrations of carbon dioxide (CO2). Short-term sick leave was included as well because it can influence learning.

Carbon dioxide (CO2) has traditionally been assumed innocuous at the typical levels indoors, and merely an indicator of metabolic emissions from humans (bioeffluents). Recent studies suggest that exposure to pure CO2 at concentrations of 2,500 to 4,000 ppm, the levels that occur periodically indoors, can have negative effects on mental performance in form of reduced ability for making decisions, typing and proofreading. Present study aimed to examine further these effects. Twenty-five human subjects were exposed to elevated CO2 with and without bioeffluents in a chamber.