Lower indoor carbon dioxide,
does it really help with Improved simulated decision-making performance in office workers?
research showsThe grade is C with 45 points. In a blinded six-day controlled-office study of 24 people, average computerized simulated decision scores were 15% lower near 945 ppm and 50% lower near 1,400 ppm than near 550 ppm. The endpoint was Strategic Management Simulation, not actual output, errors, or revenue, and independent studies did not reproduce the same dose-response even at 2,500 to 5,000 ppm.
ads claimVentilation can lower indoor concentration, but this trial did not test whether opening windows improves actual company productivity. Carbon dioxide is also a ventilation marker, and real spaces change VOCs, temperature, and noise at the same time.
Useful facts when choosing a product
- Three independently calibrated monitors measured carbon dioxide in real time at about 550, 945, and 1,400 ppm.
- Outdoor air was 20 or 40 cfm per person; direct carbon-dioxide tests fixed it at 40 and injected ultra-pure gas.
- The endpoint was a nine-domain computerized Strategic Management Simulation, not actual workplace output.
- Null replication studies used different populations, higher levels, and different exposure durations, preventing a direct estimate-to-estimate comparison.
What the research actually shows
Allen enrolled 24 office professionals for Tuesday-through-Thursday sessions from 09:00 to 17:00 over two weeks. They did normal work in a controlled office and completed the computerized Strategic Management Simulation. Outdoor air was 20 or 40 cfm per person; direct carbon-dioxide comparisons fixed outdoor air at 40 cfm per person and injected ultra-pure gas. Three calibrated monitors maintained about 550, 945, and 1,400 ppm. Average normalized scores were about 15% lower at 945 ppm and 50% lower at 1,400 ppm, with seven of nine domains declining at each increase. A United Technologies gift supported the study and its research center gave limited design input on adding a control day and third level; the article says it had no role in collection, analysis, interpretation, presentation, or drafting.
Why this is classified as C (45)
Direct control and blinding are strengths, but 24 participants, six days, a simulation, an industry gift, noncomparable null studies, and unreconstructable standardized magnitude give C with 45 points.
Counterpoint. This does not prove that lower carbon dioxide necessarily improves real work. The verdict is limited to controlled simulated decision performance.
Rejudgment record. Cross-check applied — Direct carbon-dioxide control and blinding were weighed against 24 participants, six days, a simulated endpoint, industry support, uncertain replication, and an unreconstructable standardized magnitude
| Endpoint | S | Surrogate marker - laboratory or imaging measures |
| Replication | R1 | Single confirmatory trial |
| Independence | I1 | Mixed funding sources |
| Effect size | EX | The clinical size of the effect could not be judged |
The scoring table and the verdict agree (C).
Sub-claim grades by effect
This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.
| Effect (sub-claim) | Grade | Basis |
|---|---|---|
| Controlled-room carbon dioxide and simulated decision scores | C | A positive directly controlled study exists, but external results and magnitude are unstable. |
| Ventilation improves actual workplace productivity | ? | No confirmatory trial directly measuring actual work output was verified in this evidence set. |
Cross-check — Codex and Claude
Evidence Table
| Study | Design | Sample | Funding | Endpoint | Result | Weight |
|---|---|---|---|---|---|---|
| Study 1 | Double-blind controlled-office repeated-measures trial | 00 | United Technologies gift plus NIH training and academic support | Nine-domain Strategic Management Simulation scores | Average score was about 15% lower near 945 ppm and 50% lower near 1,400 ppm versus 550 ppm. | Principal directly controlled trial |
| Study 2 | Randomized balanced crossover exposure trial | 22 | NASA research | SMS and additional cognitive tasks | Did not reproduce the earlier clear impairment across 600, 1,200, 2,500, and 5,000 ppm. | Independent but noncomparable external check |
Receipt — 4 References
All 4 cited sources were verified for existence at the original page (as of 2026-08-04).
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-08-04 · Corrections: none
Cite this verdict
[Chamgap] Lower indoor carbon dioxide x simulated office decision performance — Evidence Grade C·45. 4 cited sources checked. Source: https://chamgap.com/en/verdicts/cognition/lower-indoor-carbon-dioxide-office-decision-performance/ · CC BY 4.0CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.
What this document does and does not do
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