New Sensor Technology to Measure Vehicle Emissions and Improve Urban Air Quality

Presently, air pollution is one of the biggest challenges that European cities have to deal with. As part of the Horizon 2020 research project City Air Remote Emission Sensing (CARES), a global research consortium is involved in creating new contactless exhaust measurement techniques that will allow municipalities to take emission-reducing measures.

Sensor Technology to Measure Vehicle Emissions and Improve Urban Air Quality" />

In tangible terms, the scientists are keen on creating new sensors that can be attached to crash barriers, roadsides, or traffic signs which sense the exhaust emission of passing vehicles within seconds.  

We want to monitor vehicle emissions in cities and environmental zones under real conditions, without having to interfere with free-flowing traffic.

Alexander Bergmann, Head of Institute of Electronic Sensor Systems, Graz University of Technology

He and his team are mainly responsible in the project for all facets of particle measurement—a field in which the Institute is well-known for.

Manifold possibilities of traffic regulation

“The aim is to detect the exhaust class of each individual vehicle using these measurements,” explains Bergmann. For instance, cities could add an emissions-based city toll: the greater the emissions of the car, the higher the charge would be. Entry permits into environmental zones could also be tracked automatically, wherein automatic barriers only open if the pollutant emissions of the approaching car are within the normal range.

Finally, sensor technology could be used to find and draw out of traffic those vehicles in which engine performance and thus pollutant emissions have been increased with manipulated chip tuning or particle filters.

Tuning forks as particle measurers

Bergmann anticipates economical remote sensors for emission measurement to be set for series production towards the end of the 2022 project at the latest. However, he already refers to the first favorable tests at the institute wherein conventional tuning forks are used. The particles between the forks are stimulated through laser pulses, which in turn create an acoustic signal and start to "sing" in the most real sense of the word.

Each individual particle produces acoustic signals which are recorded and played back by the tuning fork. The more particles there are, the louder the sound turns out to be. The volume can then be used to establish the number of particles in the environment.

The technology is already being employed effectively for gas measurements.

Our institute was now able to show for the first time that this also works with particles and could be a possibility for a low-cost sensor.

Alexander Bergmann, Head of Institute of Electronic Sensor Systems, Graz University of Technology

The scientists at TU Graz expect that the measuring technique will also prove its value in the metropolises of Prague, Milan, and Krakow, where the investigations will be performed in live operation as part of the CARES project.