Since the launch of LEED v5, air quality monitoring has assumed a far more prominent role, echoing the WELL Building Standard’s long-standing emphasis on continuous, spatially precise air quality data as the cornerstone of occupant health and productivity.
In this article, our team draws on years of hands-on experience—spanning diverse building types, climates, and certification journeys—to guide you through every stage of designing, installing, and maintaining an air quality monitoring network that not only meets rigorous certification criteria but also delivers actionable insights for healthier, more efficient indoor environments.
Number of Sensors for a project
A common challenge for many project teams when implementing indoor air quality (IAQ) monitoring is determining the right number of sensors needed and identifying optimal placement locations, not only to ensure accurate and representative data, but also to meet the requirements of the relevant certification protocol.
For WELL certification, the required sensor density is closely tied to the total surface area of the project and its regularly occupied zones. To simplify this calculation, our team has developed a straightforward tool that quickly estimates the number of sensors needed based on your project’s size and certification scheme(Core vs Interiors/Owner Occupied).
Calculate the number of sensors you need
In contrast, the most recent LEED v5 draft does not currently specify a defined number of IAQ sensors required per project. However, as the system evolves toward more performance-based metrics, it is anticipated that clearer guidance on sensor density will be provided in future updates by the USGBC.
Placement of the Sensors
Improper placement of indoor air quality sensors can significantly compromise the reliability of the data collected. When sensors are installed near HVAC vents, windows, or other sources of localised airflow or environmental interference, they may record false readings that do not represent actual indoor conditions. This can lead to non-compliance with certification requirements and, more critically, to inaccurate assessments of occupant exposure and comfort.
Table 1. Recommended Guidelines for Air Quality Monitoring Device Placement
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Principle
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Description
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Breathing Zone Height
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Typically between 1.1 to 1.7 meters from the floor (the height at which people breathe).
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Away from Sources
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Avoid placement near printers, kitchens, open windows, doors, or direct HVAC supply/exhaust.
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Central and Representative
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Position sensors where occupants spend the most time, not in corners, hallways, or transitional spaces.
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Stable Environment
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Avoid exposure to direct sunlight, moisture, or mechanical vibrations.
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When selecting the specific rooms for indoor air quality sensor deployment, priority should be given to spaces with the highest levels of occupancy or areas where periodic surges in occupancy, such as meeting rooms, open-plan offices, classrooms, or event spaces, are expected. These zones are where occupants spend the most time and are therefore most critical for capturing representative exposure data. Targeting these high-use areas ensures that monitoring efforts are aligned with real human activity patterns and can more effectively inform ventilation strategies, compliance, and health-related performance goals.
On-going data collection.
The installation of an indoor air quality (IAQ) monitoring sensor network offers a broad array of opportunities, ranging from increasing awareness to optimizing HVAC system performance and minimizing the risks of exposure to air pollution. However, to maximize the potential of this technology, it’s essential that the collected data is carefully managed and used effectively. Proper data management, along with regular data reuse, is crucial to unlocking the full value of the system. This enables informed decision-making that improves both building performance and occupant health over time.
To ensure the system’s continued effectiveness, it’s important to track the collected data, regularly communicate the results to tenants and visitors, and—most importantly—maintain the equipment on a consistent basis. Calibration remains one of the most critical factors in maintaining accurate readings and preventing misleading data collection, which could compromise the system’s overall performance and reliability.
Conclusion
With the introduction of LEED v5, air quality monitoring has become more prominent, in line with the WELL Building Standard’s emphasis on continuous, precise air quality data to support occupant health and productivity. This article draws from extensive experience to provide guidance on designing, installing, and maintaining a monitoring network that ensures compliance with certification standards while offering valuable insights into creating healthier indoor environments.
Proper sensor placement and management are essential for ensuring accurate data and effective performance. WELL certification links sensor density to project size and occupied zones, while LEED v5 moves toward performance-based metrics. Ongoing data collection, regular maintenance, and calibration are critical to optimizing building performance and occupant health.
By following these practices, the full potential of IAQ monitoring systems can be realized, resulting in healthier and more efficient spaces for all.
