Air sensors for everyone, everywhere
For much of the Western world, the summer of 2023 was defined by air pollution. With intense and prolonged wildfires raging across Canada, major metropolitan areas in both North America and Europe saw their air quality levels plummet – often making the simple act of going outside a potential health risk. But air pollution is by no means limited to the great outdoors – indoor air pollution can be even worse. According to some estimates, the air inside buildings can be up to five times more polluted than the air outside. “Indoor air quality, as it is today, is often so bad that it severely affects our cognitive performance, productivity and health,” says Henrik Rödjegård, research manager at Senseair. The key to monitoring outdoor and indoor air quality is sensors. But not just any sensors, smart sensors that can be mass-produced, deployed everywhere and used by everyone. With the support of the EU-funded ULISSES project, Senseair is working to build such a sensor. “Our goal is to give city planners, employers, landlords and the general public ready access to the information they need to make smart choices in relation to indoor and outdoor air quality,” adds Rödjegård.
Comprehensive air quality monitoring in real time
Using sensors to monitor air quality is not a new concept. In fact, gas sensors are widely used by both industry and agriculture to ensure the safety of personnel and to monitor and automate processes. “What is new is growing public awareness about the importance of urban indoor and outdoor air quality, which is driving demand for accurate, low-cost and mobile gas sensor technology,” explains Rödjegård. Sensitive and robust, optical gas sensors offer the highest level of stability and specificity. Unfortunately, their high cost, high level of power consumption and big size make them less than ideal for widespread use. To address these limitations, the ULISSES project has developed new technologies that will enable compact, low-cost, low-power and networkable gas sensor nodes capable of providing comprehensive air quality monitoring in real time.
Integrated into the internet of things
According to Rödjegård, because the ULISSES millimetre-sized solution-on-a-chip optical gas sensors work in the mid-infrared spectral range, they can be mass-produced and integrated into portable devices. “Our sensors rely on integrated waveguides, which are very tiny optical fibres guiding light on the surface of a chip,” he says. “They also use such 2D materials as graphene and platinum diselenide, which can both generate and detect infrared light by converting it into an electric signal.” This innovative use of cutting-edge technologies means the ULISSES solution can be integrated into the internet of things and a range of mobile, everyday devices. “This opens the door to such practical solutions as generating localised air quality maps and providing users with geotagged air quality data and alerts,” adds Rödjegård.
Making informed decisions about the air we breathe
In addition to developing the technology, the project demonstrated that its chips could produce long enough wavelengths for high-performance gas sensing. Researchers also verified the functionality of all required subcomponents in the full system. “While our work on integrating graphene into sensor chips represents a major advancement for the scientific community, for you and me, it means being able to make informed decisions about the air we breathe,” concludes Rödjegård.
Keywords
ULISSES, air sensors, internet of things, air quality, air pollution, smart sensors