Advancing Atmospheric Hydrogen Emission Quantification Through Airborne Online Mass Spectrometry

Accurate emission measurements are critical for assessing the climate impacts of gases released by human activities. While robust and widely applied methods exist for quantifying carbon dioxide and methane emissions, comparable approaches for atmospheric hydrogen remain less mature. Recent advances in analytical instrumentation, however, are beginning to close this gap. Advanced Monitoring Solutions (adMS) has developed a fast-response (1 Hz) mass spectrometer (H₂MS) capable of measuring atmospheric hydrogen with sub-ppb precision. These direct, rapid, and precise measurements enable established emission quantification techniques to be extended to hydrogen [1].

In 2025, as part of the Hydrogen Emissions Quantification (HEQ) project – a collaboration between adMS and Equinor – we applied and evaluated multiple approaches to quantify hydrogen emissions at an operational industrial site. In this study, we present two emission quantification methods based on airborne online mass spectrometry.

First, the H₂MS analyzer was deployed aboard a helicopter to perform 1 Hz measurements of atmospheric hydrogen. Helium was released at a known rate at the site and used as a tracer, enabling application of the tracer ratio method. To support this approach, a second mass spectrometer (HeMS) was developed to provide highly precise, online measurements of atmospheric helium. These observations represent the first demonstration of real-time airborne monitoring of both hydrogen and helium and show that fast, direct hydrogen measurements can be integrated into established emission quantification frameworks. While the tracer ratio method is demonstrated here, the rapid response of the H₂MS analyzer also enables the application of other emission quantification approaches previously used for methane, including airborne mass balance and inverse modeling techniques.

In addition, we investigated an alternative measurement strategy using a drone-lifted 200 m sampling line to quantify hydrogen emissions from a 100 m-high flare. This approach highlights the potential of unmanned aerial systems to access complex emission geometries that are difficult to sample using conventional ground-based techniques.

[1] Roudot, Malgven and Piel, Felix and Sobolev, Nikita and Mikoviny, Tomas and Wisthaler, Armin and Krohl, Victoria, A New Analytical Framework for Industrial Hydrogen Emissions Quantification: Validation and First Results (September 29, 2025). Available at SSRN: https://ssrn.com/abstract=6041754 or http://dx.doi.org/10.2139/ssrn.6041754