The smart, mobile and energy-efficient greenhouse gas sensor
As climate change increases the risk of extreme weather events, there is a pressing need to monitor the contributory greenhouse gases, especially carbon dioxide, nitrous oxide and methane. While the emissions monitoring systems used by many national agencies are highly sensitive – able to distinguish between different atmospheric gases – they tend to be complex, bulky and expensive. Consequently, they are employed chiefly as static reference points, installed in only a few specific locations. “To offer a more comprehensive picture you would need a significant number of such emissions monitoring systems, covering large areas,” according to Albert Romano-Rodriguez (website in Spanish), project coordinator of the NEOGAS project, which was funded by the Marie Skłodowska-Curie Actions programme. To increase the options available to authorities and experts, NEOGAS has developed a proof of concept for a low-energy gas sensing device which will leverage internet of things (IoT) functionality for forecast modelling. “While there is still room for improvement, we were particularly satisfied that our device remained operational for up to a few weeks, still providing gas sensing measurements,” adds Romano-Rodriguez, from the Department of Electronic and Biomedical Engineering, University of Barcelona, the project host.
Building a highly efficacious device
The project’s sensing device was made from a highly porous conducting polymer, known as a metal–organic framework, whose electrical resistance changes – at room temperature – when exposed to gases. The Department of Electronic and Biomedical Engineering synthesised the material, prepared the resistor and then tested the device by measuring its electrical resistance when exposed to carbon dioxide and methane – the main greenhouse gases. To test the devices, the sensors were put into gas-tight test chambers. After the gases or gas mixtures under investigation were introduced, the sensor’s electrical resistance was measured. “Changes in the device’s resistance were recorded at methane and carbon dioxide concentrations below their actual levels in the air, demonstrating the efficacy of our proof of concept,” says Romano-Rodriguez.
Internet of things functionality will enable advanced modelling
Under the global Climate Monitoring Mechanism, the European Commission must produce an annual progress report, therefore innovations such as the NEOGAS sensing device could prove indispensable. Despite the promising lab-based results, for the NEOGAS device to reach its full potential, a number of steps will first have to be undertaken. Combining sensing functionality with that of IoT offers an especially exciting avenue, as the collected data could inform modelling of the generation and distribution of human-induced greenhouse gas emissions – crucial for evidence-based mitigation and adaptation planning. Towards this end, the team are now developing an energy-efficient printed circuit board, for integration with the device and on which the sensor can be fitted. Meanwhile, the team is also focused on improving the properties of the device’s materials, to ensure stability over time and reduce degradation, alongside the device’s sensing properties to increase sensitivity to interfering gases, especially those present in ambient humidity. “When we are finished, our compact integrated nanoelectronic nose will offer significant advantages over traditional devices. By providing a large amount of data with high spatial resolution, our system could complement current approaches,” concludes Romano-Rodriguez.
Keywords
NEOGAS, sensor, greenhouse gas, carbon dioxide, methane, internet of things
