An electronic nose to detect harmful atmospheric free radicals

An international project involving researchers from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) is receiving 3.2 million euros from the European research and innovation program “Horizon 2020” to develop a cost-effective method for measuring certain air pollutants. The team, whose members come from both industry and science, aims to develop electrical sensors to detect harmful particles in the atmosphere. Air pollution is considered to be a major cause of over 400,000 premature deaths in the European Union each year. However, measuring it accurately still poses major challenges for researchers.

Although the harmful effects on the health of certain atmospheric pollutants, called free radicals, have been known for a long time, their detection and measurement are still technologically very complex. “These free radicals are reactive compounds that cause chemical processes in the atmosphere, thus impacting climate change and the formation of acid rain or photochemical smog – all of which are harmful to human health and the environment.” , explains the project manager, Professor Justin Holmes of the University. College Cork (UCC) in Ireland. Health is affected both inside and out.

The project team includes researchers from UCC, HZDR, York University (UK), National Technical University of Athens (Greece), Bulgarian company Smartcom and UCC Academy. Supported by an external consultant from UK-based air quality firm Airlabs, Holmes and his team are working to develop cost-effective, high-tech instruments for measuring harmful air radicals. The plan is to use this technology in airplanes, ships and other air quality monitoring platforms.

Sensitive and highly selective sensors

“To date, only a few research groups are capable of performing such tests in only a few places in the world. The process involves complex spectroscopic methods using large, expensive and unwieldy equipment, which greatly limits our knowledge of chemical processes. in the atmosphere and therefore our ability to control air quality and climate change, ”says Dr Yordan Georgiev of the HZDR Institute of Ion Beam Physics and Materials Research, highlighting the motivation behind the project, which is called “RADICAL”.

The international team now wants to eliminate this bottleneck by developing new methods of detecting harmful radicals: “We want to create a technology that can be implemented relatively easily around the world. We do this by working with industry partners to advance the development of precision sensors that lend themselves to mass production, so that we can ultimately provide real-time data on distribution and distribution. transmission of free radicals in the atmosphere everywhere ”, summarizes Georgiev the objective of the project. HZDR researchers involved in the project are responsible for manufacturing electrical sensors to detect free radicals in the atmosphere. They are based on silicon nanowires, which are in a way the receptors of an electronic “nose”.

Detect radicals in the world in real time

The sensor mechanism basically works like this: Electrically charged target molecules interact with the surface of the nanowire, changing the electrical conductivity of the wire. These interactions are thus directly converted into easily detectable electrical signals. Scientists ensure the selectivity of very sensitive sensors by functionalizing the surface of the nanowire, by affixing on its surface a layer of molecules which will bind only the target molecules.

Project partner Professor John Wenger, who is director of the Atmospheric Chemistry Research Center at UCC, believes the technology goes far beyond the current state of the art and could be implemented in n any operational weather and air quality station in the world. This would dramatically improve the ability to monitor and control air quality, enable more accurate climate predictions, and ultimately improve the quality of life for all of us.