Short answer: A controlled office-exposure experiment found substantially higher cognitive-test scores when participants experienced simulated green conditions, and still higher scores when those conditions included more outdoor-air ventilation. The result is meaningful evidence that indoor environmental quality can affect performance on cognitive tests. It does not prove that every green-certified building, product, or renovation automatically improves employees’ thinking, productivity, health, or intelligence.
The evidence comes from a small, tightly controlled study rather than a trial of many occupied certified buildings. Understanding the design, the measured outcome, and the limitations is essential before translating the headline into a construction or facilities decision.
As an Amazon Associate I earn from qualifying purchases.
What the study was designed to find out
Joseph G. Allen and coauthors examined whether office conditions associated with conventional and green buildings were linked to cognitive performance. Their paper, published in Environmental Health Perspectives (advance publication October 26, 2015; journal volume dated 2016), is available in full from the original study.
Do these 3 things before closing this tab:
1Fix the driver behind crashes, sound loss and screen glitches2Clear out junk files and repair common Windows errors3Scan for outdated or missing drivers - takes under a minuteThe researchers did not compare a portfolio of buildings carrying different certification labels. Instead, they placed professional-grade employees in an environmentally controlled office space and changed specific exposures: volatile organic compound (VOC) concentrations, outdoor-air ventilation, and carbon-dioxide (CO2) conditions. This isolates indoor environmental variables more effectively than a simple comparison between two naturally different buildings.
#1 Best Overall
- Know your air – An Alexa air quality monitor that makes it easy to understand what’s in your indoor air.
- Track and measure – Our indoor air quality monitor keeps tabs on 5 key factors: particulate matter (PM 2.5), volatile organic compounds (VOCs), carbon monoxide (CO), humidity, and temperature.
- Stay informed – Get an indication of current indoor air quality from the color-coded LED, and detailed information and an easy-to-understand air quality score in the Alexa app.
- Real-time alerts - Get notifications on your phone or announcements on Echo devices when Alexa detects poor indoor air quality.
- Automate climate control - Enable Routines to turn on or off your compatible Alexa devices, such as air purifiers, dehumidifiers, and fans, when the indoor air quality sensors detect changes.
The central question was therefore narrower than “Are green buildings better?” It was whether people perform differently on an objective cognitive assessment when exposed to particular indoor-air conditions that the researchers defined as Conventional, Green, and Green+.
How the controlled exposure experiment worked
Twenty-four professional-grade employees from the Syracuse, New York, area took part. Each participant spent six complete workdays, from 9 a.m. to 5 p.m., in the controlled office room. Repeated measurements allowed researchers to compare the same people across conditions instead of relying only on differences between unrelated groups.
Participants were blinded to the test conditions, and analysts were also blinded during the relevant assessment process. The investigators worked to characterize possible environmental confounders, while keeping the room and schedule consistent. These design features strengthen the comparison, but they do not turn the experiment into a study of every type of green building or every office population.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
| Study element | What was reported |
|---|---|
| Participants | 24 professional-grade employees recruited in the Syracuse, New York, area |
| Exposure schedule | Six full workdays, 9 a.m.–5 p.m. |
| Setting | Environmentally controlled office space |
| Conditions | Conventional, Green, two Green+ conditions, and separately elevated-CO2 conditions |
| Outcome | Objective higher-order cognitive-function assessment with nine functional domains |
| Reported statistical comparison | p < 0.0001 for the reported Conventional-versus-Green comparisons |
What “Conventional,” “Green,” and “Green+” meant
Conventional condition
The Conventional condition represented office conditions with higher VOC concentrations than the green simulations. It served as the study’s comparison condition, not as a claim that every conventional office has identical pollutant levels.
Green condition
The Green condition used lower VOC concentrations than Conventional. It represented a cleaner indoor-air profile within the controlled room. The label describes the exposure prepared by the researchers; it is not a certification category and should not be treated as proof that a particular building rating system produces the same result.
Green+ conditions
The Green+ conditions combined the lower-VOC environment with higher outdoor-air ventilation. The study used two Green+ conditions and found better cognitive scores than under Conventional conditions across all nine functional domains.
Separately elevated CO2 exposures
Researchers also created conditions with artificially elevated CO2, independent of ventilation. This helped examine the relationship between CO2 exposure and cognitive scores rather than treating CO2 only as a rough indicator of how much outdoor air a room receives.
Rank #2
- 【16-in-1 Air Quality Monitor Indoor】Experience the ultimate indoor air quality monitoring with our 16-in-1 Air Quality Monitor, offering real-time detection of 9 key parameters including CO2, PM2.5, PM1.0, PM10, HCHO, TVOC, Temperature, Humidity, AQI, and Time. With 7 distinct AQI alert buzzers, this air quality tester ensures your family breathes with ease.(*Note: "16-in-1" refers to the combination of 9 key detectable parameters and 7 types of AQI alert buzzers.)
- 【Crystal Clear 7-inch Large Display】Enjoy a 7-inch LED display for sharp, clear air quality readings. Provides an instant, comprehensive view of your indoor air without navigating through menus, with three brightness settings for any lighting condition
- 【External High-Precision Sensors with 0.001 Accuracy】Equipped with advanced external high-precision sensors, this device delivers unmatched accuracy (0.001 units) by directly sampling the air. Its innovative multi-sensor array and enhanced airflow design detect even the slightest environmental changes, allowing for instant response and optimal safety. (*Note: Avoid touching the sensors or exposing them to perfumes/strong odors to maintain accuracy.)
- 【Real-Time AQI Alert Buzzers】Our air quality monitor provides real-time monitoring and alerts for pollutants like CO2, PM2.5, PM1.0, PM10, HCHO, TVOC, Temperature, Humidity, and AQI, with 7 distinct alert functions. Stay informed with clear alerts and rest easy with a mute button to silence alarms. Your health and comfort are our priority. Toggle between Fahrenheit and Celsius instantly with a double-press of the "Power" button on this air quality detector.
- 【Up to 8 Hours of Runtime & Flexible USB-C Charging】 Enjoy up to 8 hours of continuous air quality monitoring on a full charge. The USB-C charging interface offers flexible power options and is compatible with widely available USB-C cables, while the included AC adapter provides convenient charging at home. Designed for effortless monitoring wherever you need it—from bedrooms and living spaces to your car and beyond.
What the cognitive results showed
Average cognitive-function scores were reported as 61% higher in the Green condition than in Conventional. Average scores in the two Green+ conditions were reported as 101% higher than in Conventional. The paper reports p < 0.0001 for the comparison.
| Comparison | Reported average cognitive-score difference | What the figure measures |
|---|---|---|
| Green versus Conventional | 61% higher | Normalized scores on the study’s cognitive assessment |
| Two Green+ conditions versus Conventional | 101% higher | Normalized scores on the study’s cognitive assessment |
The study’s abstract states: “Cognitive function scores were significantly better under Green+ building conditions than in the Conventional building conditions for all nine functional domains.” Read in context, that sentence refers to the controlled exposures and the specific assessment used by the investigators. It does not report a 101% increase in salaries, completed work, business revenue, general intelligence, or clinical health.
How to interpret the 61% and 101% figures
The percentages compare cognitive-test scores normalized across the experiment’s conditions. They are not equivalent percentage increases in workplace productivity. A cognitive assessment can detect changes in particular mental functions, while actual job performance also depends on workload, software, supervision, collaboration, fatigue, incentives, and many other factors.
Nor do the figures establish that a green label caused the improvement. The manipulated exposures were VOC levels, ventilation, and CO2 conditions in a simulated office. A certification may cover a broad collection of design, construction, energy, water, materials, and operational criteria; the experiment did not test certification as an independent variable.
The most defensible reading is that the participants performed better on the study’s cognitive tasks under the lower-VOC and higher-ventilation exposures than under the Conventional exposure. That finding supports attention to indoor environmental quality, while leaving the size of any effect in an ordinary occupied building uncertain.
What the associations with VOCs and CO2 add
Allen and colleagues reported independent associations between VOCs and CO2 and cognitive scores. In practical terms, the data linked cleaner air and the tested CO2 conditions with differences in measured cognitive performance after the researchers accounted for the study’s analytical model.
Those associations should not be converted into a universal CO2 rule or a claim that one reading predicts an employee’s output. CO2 can reflect ventilation and occupancy, but the experiment also manipulated CO2 directly. VOC mixtures likewise vary by source and composition; a single aggregate concentration does not describe every pollutant or every health effect.
Rank #3
- High Accuracy & Fast Refresh Data: With this smart sensor, the PM2.5 accuracy is ±15 µg/m³ while temperature and humidity accuracies are ±0.54°F and ±3%RH.The two-second correction data feature shows the latest changes in PM2.5, temperature, and humidity.Keep sensor clear for accurate detection.
- Multifunctional Air Quality Detector: The GoveeLife Air Quality Monitor conveniently measures 3 important indexes for indoor air quality, including PM2.5, temperature, and humidity.
- Switchable Display: Press the top button for the clock & PM2.5 display. Long press for 2 seconds to switch to bright screen mode & night mode. The LED indicator displays 4 levels of ambient air quality. 2.4G Wi-Fi is required to display the time.
- Connect with GoveeHome Appliances: Set your target air quality and link with your other GoveeHome smart appliances. GoveeLife air purifiers, humidifiers, and space heaters will turn on and off automatically when the indoor air quality changes.
- H5106 needs to be connected to a power source and supports GoveeLife devices: Smart Air Purifiers - H7126, H7120, H7124, H712C, H7122, H7123; Humidifiers - H7140; Fans - H7100, H7102
Why the result does not establish a universal “green building effect”
Small, local sample
Only 24 people participated, and they were recruited from one geographic area. A repeated-measures design improves statistical efficiency, but a small local sample may not represent different ages, occupations, climates, building types, or health backgrounds.
Recommended Free Tools
Controlled simulations rather than occupied buildings
The room reproduced selected environmental conditions under laboratory-like control. Real offices introduce changing occupancy, weather, furnishings, cleaning products, equipment, acoustics, lighting, schedules, and maintenance practices. Those factors can alter both air quality and cognitive performance.
Exclusions and eligibility
People with asthma and some other characteristics were excluded. Results therefore cannot automatically be generalized to people with respiratory conditions or to every workforce demographic.
Potentially unmeasured influences
The investigators characterized potential environmental confounders and used blinding, but they acknowledged that factors not experimentally changed could still influence results. A controlled setting reduces uncertainty; it does not eliminate it.
Need for confirmation in real offices
The authors specifically called for assessments in actual office environments. A field study would need to connect measured indoor conditions with cognitive outcomes while handling practical variables such as work tasks, seasonal ventilation changes, and building operations.
Windows Errors? Fix Them Before They Spread
Repair common Windows errors and clear accumulated junk for a smoother, more stable PC - no reinstall needed.Free scan · no reinstallCrashes, No Sound, or Screen Glitches?
Random freezes, missing sound and display glitches usually trace back to one bad driver. Find and replace yours safely.Free scan · under a minuteWhat the evidence means for construction and facilities teams
The study supports treating indoor-air quality as a performance consideration, not merely a compliance item. It does not supply a universal design specification, payback period, or guaranteed productivity percentage. Teams should use it to frame questions and measurement plans rather than to promise a cognitive return before a building is occupied.
Control pollutant sources during design and fit-out
Specify and verify materials, finishes, furnishings, adhesives, sealants, cleaning products, and equipment with attention to VOC emissions. Source control is different from simply increasing airflow: removing or isolating a pollutant source can reduce the contaminant load that ventilation must dilute.
Rank #4
- 【16-In-1 Comprehensive Air Quality Tracking】
- 【Easy Single-Tap Operation with Adjustable Audio Prompt】
Design and commission ventilation deliberately
Document the outdoor-air strategy, controls, filtration, balancing, and commissioning process. Green+ in the experiment represented higher outdoor-air ventilation in combination with lower VOCs; it was not just an energy-efficiency label or an open-window preference.
Measure conditions rather than infer them from a plaque
After construction and during occupancy, verify that systems deliver their intended operation. A professional indoor-air-quality assessment can examine ventilation, VOCs, CO2, temperature, humidity, and other relevant conditions. A consumer CO2 monitor may help observe trends in a room, but the paper did not test consumer monitors, recommend a device, or show that monitoring alone improves cognition.
Separate environmental outcomes from cognitive outcomes
Record whether a project achieved its ventilation and pollutant targets, then treat any evaluation of cognitive performance as a separate measurement question. Better measured air does not by itself prove better business output.
Questions to ask before using this study in a project case
- Which indoor variables are being changed: VOC sources, outdoor-air ventilation, CO2, or several at once?
- Are the proposed conditions measured after commissioning and during normal occupancy?
- Does the claim concern a cognitive test, absenteeism, comfort, health symptoms, or actual productivity?
- Is the evidence from a controlled exposure, an occupied-building field study, or a certification analysis?
- Are the occupants and climate comparable to the population and location in the Syracuse study?
- Could higher ventilation create energy, humidity, noise, or maintenance trade-offs that need to be managed?
How to read green-building claims responsibly
A credible claim should identify the exposure, the outcome, the population, and the setting. “Lower VOC concentration was associated with higher scores on a controlled cognitive assessment” is a bounded statement. “Our green building makes workers 101% more productive” is not supported by this experiment.
For procurement or design decisions, ask for measured indoor-air results and the method used to obtain them. Ask whether the comparison is against a defined baseline and whether the result is a one-time test or an operating record. Certification can organize a project’s goals, but the study provides no comparison of certification options and no basis for ranking one label over another.
Bottom line on cognitive function and green environments
The controlled experiment provides strong evidence within its narrow conditions: participants achieved higher cognitive-test scores in simulated Green and Green+ offices than in the Conventional condition, with the largest reported difference in the higher-ventilation Green+ exposures. The 61% and 101% values describe normalized test scores from 24 participants over six workdays, not universal productivity gains.
For builders and owners, the practical lesson is to control pollutant sources, design and commission ventilation carefully, and verify indoor conditions in occupied use. For readers asking whether every green building improves cognition, the answer remains unproven. The study shows why indoor environmental quality deserves measurement and attention; it does not substitute for evidence from real offices.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
