What is the QUANT Study?
The QUANT (Quantification of Utility of Atmospheric Network Technologies) study is one of the largest evaluations of commercial sensors to date; evaluating the performance of a range of commercial products. The study focused on measuring key pollutants, including PM2.5, NO₂, and O₃, to assess the reliability, accuracy, and consistency of each device. With an increasing need for high-quality air quality data to support decision-making and public health, QUANT sought to determine which devices could meet these high standards over extended periods with minimal maintenance. The 2024 research paper by Diez, S., et, al., was published in the Atmospheric Measurement Techniques and is available to read here.
The study is a long-term evaluation of commercial air quality sensors provided a comprehensive 3-year assessment across a range of urban environments in the United Kingdom, evaluating 43 sensor devices, including 119 gas sensors and 118 particulate matter (PM) sensors, from multiple companies. It is one of the most comprehensive studies of commercial air quality sensor systems carried out to date.
The QUANT study serves as a valuable resource for those seeking to implement sensor solutions to tackle air pollution. It highlights the significant variation between systems, the incidence of corrections made by manufacturers, the effects of relocation to different environments and the long-term behaviour of the systems. We are thrilled to share that our Zephyr® air quality sensors performed exceptionally in the study, a true testament to our continuous development and innovation.
The Zephyr® Standout Performance in Sensor Evaluation
The Zephyr® monitor demonstrated outstanding performance across multiple areas of the QUANT study, distinguishing itself as a leader in air quality monitoring technology.
Minimal PM2.5 Uncertainty
Five comparable devices across five companies were tested for inter-device precision of PM2.5 measurements. Assessed using the “between sensor system uncertainty” metric (defined by CEN/TS 17660-1:2021 as us(bs,s)) and excluding units with less than 75 % data. The Zephyr sensor performed with the least uncertainty, with consistent results across the testing period.
Reproducibility of PM2.5 Measurements
The QUANT study highlighted Zephyr® air quality monitors as top performers in the reproducibility of PM2.5 measurements, achieving the highest consistency compared to other units. This high level of reproducibility is essential for accurately tracking particulate matter levels over time, especially in urban environments where PM2.5 fluctuations can be critical for air quality assessments.
Stability in PM2.5 Performance Over Two Years
Compared to three out of the four other units tested, the Zephyr® monitor maintained stable PM2.5 measurements without any noticeable drift over the two-year study period. This consistent performance without calibration drift underscores the Zephyr’s® robustness and the high-quality engineering that enables reliable, long-term monitoring for data accuracy and integrity.
Out-of-the-Box Calibration and Performance in NO₂ and O₃
The Zephyr® monitor’s “out-of-the-box” calibration proved accurate results for NO₂ and O₃, achieving high precision with minimal adjustments over multiple units. Monitors “out-of-the-box” calibration enables faster deployment and reduces operational setup time, it also reduces the risk of immediate service work or risk of inaccurate results being collected. This is particularly valuable for rapid-response applications in air quality monitoring.
Commitment to Accuracy & Quality
The QUANT study findings underscore EarthSense’s commitment to delivering high-quality air monitoring solutions that meet and exceed industry standards. EarthSense’s commitment to its proven accuracy and stability over time align closely with our strict quality assurance protocols, which are central to our product development. David Green, Head of product comments “By adhering to certifications and standards such as PAS4023 and CEN/TS 17660-1, we prioritise quality in both our sensors and the data they produce, ensuring that decision-makers and communities have the most trusted insights from our solutions. We are continuously working on ways to further improve and enhance our solutions and are working towards the latest standards”.
The QUANT study not only affirms the current strength of our Zephyr® technology but also guides our path forward. We are committed to continuous development and innovation, with plans to further enhance Zephyr® adaptability and accuracy across more complex environments and an expanded range of pollutants. Additionally, by integrating user feedback and new insights we will continue to improve our product offerings to ensure they remain among the most robust and reliable solutions for air quality monitoring.
Reference: Diez, S., Lacy, S., Coe, H., Urquiza, J., Priestman, M., Flynn, M., Marsden, N., Martin, N. A., Gillott, S., Bannan, T., and Edwards, P. M.: Long-term evaluation of commercial air quality sensors: an overview from the QUANT (Quantification of Utility of Atmospheric Network Technologies) study, Atmos. Meas. Tech., 17, 3809–3827, https://doi.org/10.5194/amt-17-3809-2024, 2024.
The 2024 research paper by Diez, S., et, al., was published in the Atmospheric Measurement Techniques and is available to read here.
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