Aerial and Ground Mobile Sensor for Atmospheric Gas Detection

Anthropogenic emissions contribute to greenhouse gases and other climate-changing gases that are significant risks to human health and the environment. Among these emissions are nitrogen (N) compounds, around 55% of which are comprised of ammonia while oxides of nitrogen and nitrous oxide make up the rest. A majority of ammonia emissions come from fertilizer and animal waste at agricultural sites.Atmospheric ammonia needs to be well quantified in these areas to better regulate and reduce nitrogen anthropogenic emissions.

Researchers from Colorado State University and Surprise, AZ, have developed an ammonia sensor based on wavelength modulation spectroscopy (WMS) utilizing a quantum cascade laser (QCL) at 10.33 μm for mobile applications. The ammonia sensor was deployed on a ground vehicle for ammonia concentration measurements in a city for automobile combustion, and on a fixed-wing plane for measurements in air for feedlot ammonia emissions. This compact (~20 L), lightweight (~3.5 kg), and battery-powered (<30 W) design operates autonomously to achieve a sensor accuracy of <~2% and precision of ~4 ppb in 1 s. This mobile sensing approach provides a scalable solution for detecting and quantifying anthropogenic emissions of ammonia in the atmosphere in industrial and agricultural settings.

Laser stability is critical for sensing low concentrations of harmful gases in the air. Laser absorption spectroscopy requires high precision and accuracy, and researchers used high-performance electronics to drive the laser system for ammonia gas detection. Wavelength Electronics' compact laser driver enabled the sensitive measurements and analysis required for ammonia gas detection for mobile deployment.

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