Do indoor carbon dioxide concentrations, reflecting ventilation and building occupancy, associate with cognitive test scores among university graduate students in classrooms with increased ventilation?
Indoor CO2 Air-Quality Monitor (J Expo Sci Environ Epidemiol 2025, PMID 40204887) — model estimates showed directionally consistent evidence that higher central and peak classroom carbon dioxide concentrations (ranging from approximately 440-1630 ppm) were associated with lower cognitive test scores. No numeric effect size is reported for Indoor CO2 Air-Quality Monitor in the source abstract.
Source: J Expo Sci Environ Epidemiol 2025, PMID 40204887 ↗ · Research map · How Magellan grades evidence · evidence confidence: low
J Expo Sci Environ Epidemiol · 2025 · PMID 40204887 · DOI 10.1038/s41370-025-00770-6
Higher classroom carbon dioxide levels, even in well-ventilated spaces, are associated with lower student cognitive test scores.
The question
Do indoor carbon dioxide concentrations, reflecting ventilation and building occupancy, associate with cognitive test scores among university graduate students in classrooms with increased ventilation?
What they tested
The study implicitly hypothesizes that higher indoor carbon dioxide concentrations will be associated with lower cognitive test scores, even in classrooms with enhanced ventilation.
How they did it
Graduate students (54 included in analysis) attending lectures in university classrooms with increased ventilation participated. Post-class cognitive performance tests (Stroop and Arithmetic) were administered via a smartphone app during the 2022-2023 academic year. Classrooms had continuous indoor environmental quality monitors providing real-time carbon dioxide concentrations. Mixed-effects statistical models were used to analyze temporally and spatially paired exposure and outcome data, examining different carbon dioxide exposure metrics and cognitive test scores.
What they found
Model estimates showed directionally consistent evidence that higher central and peak classroom carbon dioxide concentrations (ranging from approximately 440-1630 ppm) were associated with lower cognitive test scores. The strongest effect estimates were observed for 95th percentile class carbon dioxide concentrations, representing peak exposures.
What it means
Lower carbon dioxide concentrations are associated with higher cognitive test scores, even in classrooms with increased outdoor air ventilation. While not causal and with unknown underlying mechanisms, higher outdoor air ventilation appears to offer additional benefits beyond infection risk reduction by supporting student performance.
Limitations
The study notes that the findings are not causal, and the underlying mechanisms for the observed associations remain unknown.
The paper at a glance
| Title | Associations between indoor air exposures and cognitive test scores among university students |
|---|---|
| Journal | J Expo Sci Environ Epidemiol |
| Year | 2025 |
| PMID | 40204887 ↗ |
| DOI | 10.1038/s41370-025-00770-6 ↗ |
| Topic | Environment, air, water & exposures |
Read the source: PubMed record (authors, abstract, full citation) ↗ · Publisher via doi.org ↗
Where Magellan uses this paper
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Indoor CO2 Air-Quality Monitor
Controlled human-exposure experiments have found that CO2 at concentrations common indoors (around 1,000-2,500 ppm) can reduce scores on tests of decision-making and higher-order cognition, and observational, real-world, and meta-analytic studies link higher ventilation (lower CO2) to better task performance in…
An indoor CO2 (carbon dioxide) air-quality monitor measures the concentration of carbon dioxide in…
Research describes the compound or intervention studied. It is not a claim about any specific product.
Cite this page
These citations point at this summary. To cite the original paper with its full author list, use the PubMed record or doi.org.
Magellan Longevity. (2026). Do indoor carbon dioxide concentrations, reflecting ventilation and building occupancy, associate with cognitive test scores among university graduate students in classrooms with increased ventilation? [Plain-English summary of J Expo Sci Environ Epidemiol 2025, PMID 40204887, DOI 10.1038/s41370-025-00770-6]. Magellan Longevity. https://magellanlongevity.com/study/d40204887.html@misc{magellan_d40204887,
title = {Do indoor carbon dioxide concentrations, reflecting ventilation and building occupancy, associate with cognitive test scores among university graduate students in classrooms with increased ventilation?},
author = {{Magellan Longevity}},
year = {2026},
howpublished = {\url{https://magellanlongevity.com/study/d40204887.html}},
note = {Plain-English summary of PubMed PMID 40204887; DOI 10.1038/s41370-025-00770-6; J Expo Sci Environ Epidemiol 2025. Reviewed by Gabriel Radu, DO},
urldate = {2026-08-11}
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