Health outcome · function
Cognitive performance
Also: cognitive function, productivity
Attention, decision-making, memory and reaction time as measured by standardised tasks. Indoor CO₂ and volatile compounds at ordinary office and classroom levels measurably reduce it, and fine particles are linked to long-term cognitive decline.
Why it matters indoors
Controlled studies in which people work in rooms at 600, 1000 and 2500 ppm CO₂ — with everything else constant — show a stepwise fall in decision-making scores, largest on complex tasks such as strategy and information use. Field studies in schools and offices find the same pattern with ventilation rate; long-term epidemiology links PM₂.₅ exposure to faster cognitive decline and dementia in older adults. The effects are moderate per person but apply to everyone in the room, every day.
Indoor factors with evidence
12 of 15 Findings — those with the strongest study design.
| Factor | Effect | Population | Study design | Source | Checked |
|---|---|---|---|---|---|
| Carbon dioxide (CO₂) | difference -13.57 | college students · test chamber | controlled chamber exposure experiment with college students in Chongqing: 4-hour exposures to 500 ppm and 2500 ppm pure CO2 with and without added negative air ions, cognitive test battery and symptom questionnaires | F-0399 Effects of increasing indoor negative air ions on cognitive … (2023) | machine |
| Carbon dioxide (CO₂) | difference 11 | adult volunteers · exposure chamber (office-like) | blinded controlled exposure study with balanced crossover order: 22 participants in six groups exposed in an office-like chamber to CO2 at 600, 1,000 and 2,500 ppm in three 2.5-hour sessions on one day, ventilation rate and temperature constant, computer-based Strategic Management Simulation test of decision-making performance analysed with analysis of variance | F-0416 Is CO2 an Indoor Pollutant? Direct Effects of Low-to-Moderat… (2012) | machine |
| Carbon dioxide (CO₂) | difference 23 | adult volunteers · exposure chamber (office-like) | blinded controlled exposure study with balanced crossover order: 22 participants in six groups exposed in an office-like chamber to CO2 at 600, 1,000 and 2,500 ppm in three 2.5-hour sessions on one day, ventilation rate and temperature constant, computer-based Strategic Management Simulation test of decision-making performance analysed with analysis of variance | F-0417 Is CO2 an Indoor Pollutant? Direct Effects of Low-to-Moderat… (2012) | machine |
| Carbon dioxide (CO₂) | difference 44 | adult volunteers · exposure chamber (office-like) | blinded controlled exposure study with balanced crossover order: 22 participants in six groups exposed in an office-like chamber to CO2 at 600, 1,000 and 2,500 ppm in three 2.5-hour sessions on one day, ventilation rate and temperature constant, computer-based Strategic Management Simulation test of decision-making performance analysed with analysis of variance | F-0418 Is CO2 an Indoor Pollutant? Direct Effects of Low-to-Moderat… (2012) | machine |
| Carbon dioxide (CO₂) | difference 94 | adult volunteers · exposure chamber (office-like) | blinded controlled exposure study with balanced crossover order: 22 participants in six groups exposed in an office-like chamber to CO2 at 600, 1,000 and 2,500 ppm in three 2.5-hour sessions on one day, ventilation rate and temperature constant, computer-based Strategic Management Simulation test of decision-making performance analysed with analysis of variance | F-0419 Is CO2 an Indoor Pollutant? Direct Effects of Low-to-Moderat… (2012) | machine |
| Carbon dioxide (CO₂) | decision-making performance filed under cognitive-performance | adult volunteers · exposure chamber (office-like) | blinded controlled exposure study with balanced crossover order: 22 participants in six groups exposed in an office-like chamber to CO2 at 600, 1,000 and 2,500 ppm in three 2.5-hour sessions on one day, ventilation rate and temperature constant, computer-based Strategic Management Simulation test of decision-making performance analysed with analysis of variance | F-0420 Is CO2 an Indoor Pollutant? Direct Effects of Low-to-Moderat… (2012) | machine |
| Carbon dioxide (CO₂) | decision-making performance filed under cognitive-performance; the focused activity scale moved in the opposite direction | adult volunteers · exposure chamber (office-like) | blinded controlled exposure study with balanced crossover order: 22 participants in six groups exposed in an office-like chamber to CO2 at 600, 1,000 and 2,500 ppm in three 2.5-hour sessions on one day, ventilation rate and temperature constant, computer-based Strategic Management Simulation test of decision-making performance analysed with analysis of variance | F-0421 Is CO2 an Indoor Pollutant? Direct Effects of Low-to-Moderat… (2012) | machine |
| Carbon dioxide (CO₂) | primary outcome null result of a crossover trial; the Results sentence 'There were no significant exposure effects on cognitive performance' is split across a line break in the text layer | schoolchildren aged 10-12 years · climate chamber (sleeping) | double-blind, placebo-controlled, fully balanced crossover trial: 36 children aged 10-12 years slept in a climate chamber in 6 groups under three conditions seven days apart in random order (high ventilation with CO2 at 700 ppm; high ventilation with added pure CO2 at 2000-3000 ppm; reduced ventilation with CO2 at 2-3000 ppm and bioeffluents), CANTAB cognitive test battery in the evening and next morning, sleep monitored with wrist actigraphs | F-0449 The effect of air quality on sleep and cognitive performance… (2023) | machine |
| Particulate matter (PM₂.₅ and PM₁₀) | beta -0.13 (-0.22–-0.04) per 53.2 z-score per interquartile range increase | — · home | prospective study of Chinese adults (INTERMAP-China): exposure to household air pollution estimated and related to z-standardised domain-specific and overall cognitive scores from the Montreal Cognitive Assessment | F-1782 Tseng Household air pollution from solid fuel use as a dose-depend… (2022) | machine |
| Black carbon | beta -0.10 (-0.19–-0.01) per 0.9 z-score per interquartile range increase | — · home | prospective study of Chinese adults (INTERMAP-China): exposure to household air pollution estimated and related to z-standardised domain-specific and overall cognitive scores from the Montreal Cognitive Assessment | F-1783 Tseng Household air pollution from solid fuel use as a dose-depend… (2022) | machine |
| Carbon dioxide (CO₂) | ratio 2.143 | elementary school children · classroom | cross-sectional study of 1,019 students at 51 elementary schools in Coimbra (Portugal): questionnaire on symptoms and diseases with indoor air quality measurements in classrooms in fall/winter and spring/summer | F-0395 Indoor air quality and health in schools (2014) | machine |
| Carbon dioxide (CO₂) | the study says the result is relevant for short-term exposure, and temperature and ventilation cannot be separated in it | — · classroom | field study in classrooms with multivariable multilevel regression: indoor temperature and carbon dioxide, as markers of the ventilation rate, related to the speed and accuracy of cognitive tasks after adjustment for confounders | F-1653 Combined effects of ventilation rates and indoor temperature… (2022) | machine |
Each row is one Finding — a sentence as printed in one study, recorded with its page in the Coridum Knowledge Base. Follow the Finding number for the exact wording and the citation. Checked says who verified the row: machine means every automatic check passed and the surrounding text was read; person means someone read the sentence in the document. Rows are re-checked by a person over time. The studies are curated in the Coridum Knowledge Base; the reading of them together is a Claim, shown separately.
In the literature
- Effects of increasing indoor negative air ions on cognitive performance and health of… (2023). doi:10.1155/2023/8298339 CKB 0687
- Indoor environmental quality and learning outcomes: protocol on large- scale sensor deployment in schools (2020). BMJ open. doi:10.1136/bmjopen-2019-031233 CKB 0679
- Air Quality Monitoring in Schools: Evaluating the Effects of Ventilation Improvements on Cognitive (2025). Cureus. doi:10.7759/cureus.83306 CKB 1149
Studies in the Coridum Knowledge Base in which this term is used. The definition follows standard usage in WHO, ISO and textbook sources; it is not quoted from these papers.
CKB = document number in the Coridum Knowledge Base, our curated library of peer-reviewed studies. Follow the DOI for the original paper.
Cite this page
Coridum Research. Cognitive performance. Coridum Knowledge G-0059, 16 September 2026. https://coridum.com/k/G-0059/