Ellona wins four awards at the 2025 AIRLAB Microsensors Challenge.

Four awards for the WT1 Lite

Following several months of evaluation, the WT1 Lite received the following four awards:

• Outdoor Air – Ghana – Accuracy Award, for the accuracy of its ozone (O₃) and fine particulate matter (PM₂.₅) measurements, as well as its multi-pollutant assessment;
• Outdoor Air – India – Overall Performance Award, awarded jointly for its overall performance in outdoor air quality monitoring;
• Outdoor Air – India – Accuracy Award, for the accuracy of its nitrogen dioxide (NO₂) measurements and multi-pollutant assessment;
• Outdoor Air – Across All Sites – Accuracy Award, for the accuracy of its PM₂.₅ measurements across all evaluation sites.

Ellona thus received three Accuracy Awards, along with an Overall Performance Award, jointly awarded in India.

These distinctions demonstrate the WT1 Lite’s ability to deliver accurate and robust measurements in both temperate and tropical climates, as well as in environments with widely varying pollution levels and profiles.

An international challenge dedicated to evaluating microsensors

Airparif is the accredited non-profit organization responsible for monitoring air quality in the Île-de-France region. Through AIRLAB, its open innovation laboratory, it periodically organizes an independent evaluation of microsensor-based air quality monitoring solutions.

The AIRLAB Challenge aims to evaluate these systems under real-world operating conditions and provide local authorities, companies, and other potential users with objective information to help them select the solutions best suited to their needs.

Following four previous editions held in 2018, 2019, 2021, and 2023, the 2025 Challenge expanded its international scope, with evaluations conducted in three countries:

• Paris, France, with Airparif;
• Accra, Ghana, with Afri-SET WEST;
• Bengaluru, India, with Indi-SET, represented by CSTEP.

Challenge partners:

Nine WT1 Lite units tested over four months

For this campaign, three WT1 Lite units were tested at each of the three evaluation sites, representing nine devices in total.

The tests were conducted over four months, from mid-September 2025 to mid-January 2026, under highly contrasting climatic conditions and pollution contexts.

This geographical diversity made it possible to assess the performance of the microsensors in Paris’s temperate climate, as well as in the tropical environments of Accra and Bengaluru, which are characterized by different temperatures, humidity levels, and emission profiles.

A comparison with certified air quality monitoring stations

At each site, the WT1 Lite units were co-located with certified Air Quality Monitoring Stations.

The measurements produced by the WT1 Lite units could therefore be compared directly with data provided by reference instruments compliant with the applicable standards.

This methodology enabled the independent and objective assessment of several essential criteria, including:

• measurement accuracy;
• comparison with reference instruments;
• linearity;
• reproducibility;
• performance stability;
• data recovery and availability;
• solution utility;
• ease of use;
• environmental footprint;
• cost.

The best accuracy results in several key categories

The comparison with the reference stations highlighted the WT1 Lite’s excellent metrological performance.

Among the solutions evaluated, Ellona achieved the best accuracy results:

• for O₃, PM₂.₅, and multi-pollutant assessment in Ghana;
• for NO₂ and multi-pollutant assessment in India;
• for PM₂.₅ across all evaluation sites.

The WT1 Lite was also recognized as one of the top-performing systems in the Outdoor Air – Monitoring category in Bengaluru and as the most accurate multi-pollutant system in Ghana.

The evaluations also highlighted:

• excellent accuracy for carbon monoxide in Bengaluru;
• very good to excellent performance for PM₂.₅, NO₂, O₃, NO, and PM₁, depending on the site;
• excellent utility;
• very good ease of use.

An evaluation also conducted in an indoor environment

In addition to the outdoor air campaigns, the 2025 edition included a confined indoor environment: a Paris underground railway station.

This evaluation was conducted in partnership with Île-de-France Mobilités and SNCF Gares & Connexions. Its aim was to assess the performance of the solutions in a complex transport environment characterized by specific particulate matter concentrations and profiles.

This new configuration further broadens the scope of the Challenge by addressing air quality monitoring challenges in underground transport environments.

Recognition of Ellona’s expertise

These four awards recognize the work carried out by Ellona’s teams to develop multi-pollutant monitoring solutions capable of delivering accurate, reliable, and actionable data.

They also validate our Environmental Intelligence approach, which combines connected monitoring systems, real-time data acquisition, and advanced analytical tools to better understand environmental phenomena and support informed decision-making.

The diversity of the evaluation sites and the comparison with certified air quality monitoring stations further strengthen the significance of these results and demonstrate the robustness of the WT1 Lite under a wide range of real-world conditions.

Discover the summary of the Ellona WT1 Lite results

To gain a clearer understanding of the results achieved by the WT1 Lite in the 2025 AIRLAB Microsensors Challenge, explore this summary of the evaluation conditions and protocol, the main criteria assessed, and the performance measured across the various test sites.

Read the WT1 Lite technical report summary