Imperial: large-scale demonstration of mobile wireless sensors in measuring air quality

Researchers at Imperial College have staged a large-scale demonstration to show people from transport authorities and industry how small mobile sensors can be used to improve the monitoring and management of air quality in urban areas.

“There is a lot that we do not know about air quality in our cities and towns because the current generation of large stationary sensors don’t provide enough information,” says project director John Polak, from the Centre for Transport Studies at Imperial College London. “We envisage a future where hundreds and thousands of mobile sensors are deployed across the country, to improve the way we monitor, measure and manage pollution in our urban areas.”

Three new types of sensors were deployed in demonstration, measuring multiple types of traffic emissions and noise pollution. The team received data from 100 sensors close to Imperial’s site in London’s South Kensington, and in Leicester, Gateshead and Cambridge, to test how the sensors operate from different locations.

The sensor technology makes it possible to measure and model air quality in unprecedented detail, improving understanding about pollution hotspots and making it possible to analyse how urban design contributes to air quality.

The researchers also modelled pollution clouds in 3-D, taking data from sensors on traffic lights and street lamps, with the aim of understanding how pollution forms, lingers and dissipates in high emission zones. It is hoped this will lead to insights about whether, for example, poor signalling causes traffic congestion, which then contributes to reduced air quality.

The sensors can measure up to five traffic-generated pollutants simultaneously, including nitrogen oxides and sulphur dioxides, taking measurements at 5 second intervals. This is fast enough for sensors to operate on moving cars and buses.

Another type of sensor can be attached to pedestrians and cyclists to measure the pollution that they are exposed to as they move around. These are small enough to fit into a pocket, and can detect car pollutants and other contaminants including carbon monoxide from cigarette smoke. Data from the sensor is transmitted by the wearer’s mobile phone.

The project, entitled Mobile Environmental Sensing System Across Grid Environments, is led by Imperial and brings together research groups in the fields of e-Science, transport, sensors and communications technologies from the Universities of Cambridge, Leeds, Newcastle and Southampton.