People living in cities have grown used to the notion of air quality. Weather forecasts now systematically mention it and are able to do so thanks to networks of ground-based air quality monitoring devices. But whilst these networks do the job, they are not yet dense enough and their set-up and maintenance are not cheap. “Researchers have tried to move towards geo-statistical methods based on the interpolation of in situ observations to reduce cost and enhance spatial resolution. But uncertainties are a major drawback. They also investigated the use of atmospheric pollution transport models, but these require accurate estimates of initial and boundary conditions as well as high-quality and up-to-date emissions inventories. This information is not always available, while the models themselves demand high computer power and struggle to make predictions for complex terrains,” says Denis Sarigiannis, professor of Chemical Engineering at the Aristotle University of Thessaloniki and coordinator of the project ICARUS (Integrated Climate forcing and Air pollution Reduction in Urban Systems). ICARUS has taken a completely different route. The team optimised existing models and computational techniques to reduce uncertainty through a data fusion approach, developed wearable sensors allowing citizens to assess their exposure, and estimated health impact based on the uptake of pollutants instead of concentration in ambient air. Their key motivation was to inform citizens and advise them on more environment-conscious behaviour, while also capturing societal interactions to assess the impact of policy.
A tale of nine cities
The project’s technologies were tested in nine cities representative of the various urban settings found across Europe: Basel, Brno, Ljubljana, Roskilde, Stuttgart, Thessaloniki, Athens, Milan and Madrid. “We selected these cities carefully to cover the whole spectrum of green urban management. They are of different sizes, with very different social, cultural, climatic and environmental conditions, and they had all already adopted a number of technical and non-technical measures to reduce air pollution and carbon footprint,” Sarigiannis explains. The project team assessed a total of 45 policies in cooperation with local authorities. They used a fully integrated impact assessment paradigm to estimate the changes in emissions, concentrations, exposure and health impacts brought by those policies. They also carried out cost-benefit and cost-effectiveness analysis for each of them. “We sent the results to local authorities so that they could have a better reading of how these policies really performed,” adds Sarigiannis.
Over 600 citizens participated in exposure campaigns. They were asked to wear a physical activity wristband recording steps, distance, type of activity, heartbeat and sleeping patterns, as well as another one capable of absorbing a wide range of organic chemicals. They also wore a custom-built portable sensor that captured their exposure to PM, temperature, humidity and their location, and even received a static sensor measuring indoor air quality in their homes. “Participants answered a questionnaire and received a feedback report with data and charts. They expressed high interest in ICARUS activities and outcomes,” Sarigiannis notes. For the others, the ICARUS consortium developed a mobile app called RQuality which promotes wellness and environmental awareness. Any citizen in the test cities can freely use the app to track air quality data in real time and be informed of individual exposure to airborne chemicals. The app tracks consumption patterns and lifestyle choices to estimate their carbon footprint, and even reports incidents affecting air quality in their area. Local authorities aren’t left empty-handed either. The project’s decision support system (DSS) will help them improve air quality and assess climate change governance, as Sarigiannis explains. “DSS users can perform a fully integrated assessment of both predefined policies and new policy scenarios. They can estimate impacts in terms of changes in air pollution and population exposure, and conduct a full cost-benefit analysis.” With this and ICARUS’s three proposed pathways for the realisation of green cities within the next 50 years, all they have to do now is take decisive action.
ICARUS, green cities, air pollution, monitoring, citizen empowerment, air quality, RQuality