Sensors on streetlights could monitor air pollution

Small sensors mounted on streetlights could help monitor air pollution on a much wider scale, a Swedish university has said.

Academics at the Chalmers University of Technology in Sweden have developed a small, optical nano-sensor which can be mounted onto ordinary streetlights to measure levels of nitrogen dioxide (NO2).

Researchers say that the technology, which is already in use in western Sweden, could soon be rolled out in several cities as a collaboration with the University of Sheffield is already underway.

‘Air pollution is a global health problem,’ said Chalmers researcher Irem Tanyeli. ‘To be able to contribute to increased knowledge and a better environment feels great.

‘With the help of these small, portable sensors, it can become both simpler and cheaper to measure dangerous emissions extremely accurately.’

Researchers say the new optical nano-sensors can be installed on ordinary streetlights. Credit: Aleksandr Neplokhov from Pexels

The hi-tech sensors have been developed in collaboration with the Gothenburg-based company Insplorion and the financier Mistra Innovation.

The sensors have the capability to detect low concentrations of NO2 down to parts-per-billion (ppb), and are built on an optical phenomenon called a plasmon.

The sensors are now being tested in various environmental conditions, such as on a streetlight in Gothenburg, the roof of a shopping mall, and along the route of a railway tunnel construction project.

The researchers behind the sensors hope the technology can soon be integrated into other urban infrastructure such as traffic lights or speed cameras, or used to measure air quality indoors.

The Urban Flows Observatory, an air quality centre at the University of Sheffield, is now set to conduct field testing of the technology, comparing the sensors’ results with data from British air quality monitoring stations.

Professor Martin Mayfield at the Urban Flows Observatory said: ‘There is a lack of small functional nitrogen dioxide sensors on the market. We find this nanoplasmonic solution interesting, and look forward to the test results.’

As the nano-sensors can be adapted to measure other types of gases and not just nitrogen dioxide, those behind the technology say it has the potential to be further developed.

Christoph Langhammer, professor at the Chalmers Department of Physics, said: ‘Nitrogen dioxide is just one of the many substances which can be detected with the help of optical nanosensors. There are great opportunities for this type of technology.’

According to the World Health Organisation, air pollution is the single biggest environmental health risk worldwide, killing 7 million people prematurely each year.