New ‘lamp post’ gas detector to prevent millions of air pollution deaths

This innovative air quality monitoring system employs advanced laser technology to detect minuscule amounts of toxic gases in large, densely populated areas.

Featuring a network of interconnected sensors, this system can identify trace levels of various gases – including nitrogen dioxide (NO2), sulphur dioxide (SO2), carbon monoxide (CO), ozone (O3), and particulate matter – in real-time in dynamic settings such as schools, towns, and cities.

According to the World Health Organisation, ambient air pollution, resulting from high levels of toxic gas molecules and particulate matter, is responsible for the premature deaths of 4.2 million people annually.

Traditional methods of monitoring air quality in cities involve large units the size of refrigerators, costing up to £100,000. Alternatively, low-cost sensors utilise chemical reactions, but these can be inaccurate and may produce false readings.

However, the €6.9 million EU-funded project, PASSEPARTOUT, aims to deliver a compact detector that provides a comprehensive understanding of the types and concentrations of toxic gases at a far more affordable price.

PASSEPARTOUT Project Coordinator Dr William Whelan-Curtin said: “The miniature PASSEPARTOUT hyperspectral optical-based sensors will provide a comprehensive approach to understanding urban air quality. To have a widespread network and to take meaningful steps towards a smart city, current, expensive methods are not feasible.

“At present, accurate assessments of urban air are difficult. Air quality varies significantly over time, over short distances and across different areas within a city. Traditional monitoring methods struggle to capture these nuanced variations adequately. We are working to provide a system with high precision and excellent spatial resolution to detect NOx, SO2, NH3, CH4, CO, CO2, and black carbon.”

The project has aspirations to make its real-time metropolitan networks commonplace in our towns and cities.

“We would like to make the technology as common as video surveillance by installing a detector on every lamppost. As part of the project, we are developing a smartphone app to check air quality in real-time. In the future, we hope this can be integrated into Google Maps so that your journey to and from work or school can show you not just traffic hotspots but also the route with the cleanest air.

“Ultimately, we want to help save lives and help citizens everywhere enjoy clean air. At the sub-one thousand Euro price tag, our technology will enable municipalities, environmental agencies, and researchers the ability to make targeted interventions and policy decisions for a fraction of the price.”

The system operates by leveraging photothermal and photo-acoustic effects. It emits pulses or short bursts of laser light. When this laser light encounters a toxic gas molecule, the molecule absorbs the light energy, emitting a heat 'signature'. This signature is then relayed back to the system, which accurately identifies the type of harmful gas and measures its concentration.

The PASSEPARTOUT system goes a step further by using quartz tuning fork technology – or Quartz Enhanced Photo-Acoustic Spectroscopy. Dr Whelan-Curtin explains: “QEPAS is particularly useful for the detection and quantification of trace gases in challenging environments. We use a quartz tuning fork with a sharp mechanical resonance to detect the signals generated by the gas sample while suppressing the background noise. This tuning fork detects the acoustic waves generated by the gas as it heats and cools. The signal is then analysed to determine the concentration of the target gas. The exact wavelengths of the laser, or lasers, can be tuned to match the characteristic absorption spectrum of the target gas, meaning our system categorically detects specific gases, like carbon monoxide or sulphur dioxide.”

This robust sensing allows the PASSEPARTOUT detector to monitor environments, providing dynamic and to-the-minute air quality representations continuously. “Even the most tiny fluctuations in toxic gas concentrations can be captured promptly, enabling more effective and timely interventions.”

The PASSEPARTOUT team is trialling their technology in landfill sites, seaports, at the University of Bari, and in a selection of schools in Cork.

The PASSEPARTOUT project is coordinated by Munster Technological University and will conclude in 2024. It includes 19 other partners: University College Cork - National University Of Ireland, Cork (Ireland); Universita Degli Studi Di Bari Aldo Moro, Politecnico Di Bari, Etg Risorse E Tecnologia Srl, Ecospray Technologies Srl, Techno Sky Srl Technologies For Air Traffic Management, Comune Di Bari (Italy); Nanoplus Nanosystems And Technologies, Technische Universitaet Muenchen (Germany); Centre National De La Recherche Scientifique Cnrs, Universite Cote D’azur, Le Verre Fluore (France); Green Lab Magyarorszag Mernoki Iroda Korlatolt Felelossegu Tarsasag (Hungary); Argotech As (Czechia); Technische Universitaet Wien (Austria); Vario-Optics Ag, Fachhochschule Nordwestschweiz Fhnw (Switzerland); Haze Instruments, Razvoj In Proizvodnja Merilnih Instrumentov Doo (Slovenia); AUG Signals Hellas Technology Developments And Applications Hellas Single Member Private Company (Greece).