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A laser-based air quality monitor on every lamppost?

An EU-funded project called PASSEPARTOUT is developing a new gas detection network that can analyze multiple gases in real time.

The system is sufficiently compact (‘handheld’) and affordable (less than £1,000) that one imagines they could become as ubiquitous as CCTV cameras, with one on every lamppost as needed.

The system uses laser technology to detect even the smallest amount of toxic gases in large, densely populated areas.

By connecting multiple sensors to an analysis network, PASSEPARTOUT can detect traces of numerous gases (including nitrogen dioxide, sulfur dioxide, carbon monoxide, ozone and particulate matter) in real time in environments such as schools and cities.

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

‘Currently, accurate assessments of urban air are difficult. Air quality varies considerably over time, over short distances and between different areas within a city. Traditional monitoring methods struggle to adequately capture these nuanced variations. We are working on a system with high precision and excellent spatial resolution to detect NOx, SO2, NH3, CH4, CO, CO2 and black carbon.’

The system works by using photothermal and photoacoustic effects. The laser creates pulses or small bursts of laser light. When the laser light hits a toxic gas, the molecule absorbs light energy, releasing a ‘heat signature’ that is then reported to the system. The system then unmistakably identifies what the harmful gas is and how much of it is present.

It is hoped that the size and affordability of the monitors will lead to widespread adoption in urban locations.

Dr. William Whelan-Curtin says again: ‘We want to make the technology as common as video surveillance by installing a detector on every lamp post. As part of the project, we are developing a smartphone app to monitor air quality in real time. We hope that this can be integrated into Google Maps in the future, so that on your journey to and from work or school you can see not only the traffic hotspots, but also the route with the cleanest air.

‘Ultimately, we want to help save lives and help citizens around the world enjoy clean air. With a price tag of less than a thousand euros, our technology will enable municipalities, environmental services and researchers to make targeted interventions and policy decisions for a fraction of the price.’

The technology is currently being trialled at landfills, seaports, at the University of Bari and in some schools in Cork.