Visualising and evaluating objective citizen-contributed environmental information: the CITI-SENSE Citizens’ Observatory Toolbox

Abstract

Introduction: The Citizens’ Observatory Toolbox (COT) has been developed within the CITI-SENSE project (partly funded by the EU FP7-ENV-2012, grant agreement no. 308524) for collecting citizen-contributed observations of air quality. Methods: Environmental micro-sensor nodes for measuring air quality have been developed and are used to monitor NO, NO2, O3, CO, PM2.5, PM10, and noise. Static nodes (AQMesh pods) and portable nodes were deployed with different stakeholders. The portable nodes are coupled to the ExpoApp smartphone application (Android), which also collects geolocation and accelerometry data. Both the AQMesh pods and the LEOs automatically and wirelessly transmit encrypted data to dedicated Spatial and Environmental Data Service (SEDS) and Web Feature Service (WFS) databases, where they are processed for visualisation and evaluation for usefulness by users. Results: AQMesh pods with an updated algorithm (v4.1) show highest correlations (R2 = 0.76–0.81) for NO2 when comparing 15-minute averages obtained by reference instruments at municipal monitoring stations. The portable nodes, due to the challenges of micro-sensors and egomotion, are communicating real-time Air Pollution Indication (APIN) levels to users. The APIN is based upon the Common Air Quality Index (CAQI) but represents minute averages, showing potential to improve micro-environmental exposure classifications as well as personal air quality advice. Dynamic city-wide air quality maps have been produced using data assimilation techniques, fusing data from the AQMesh pods with base maps obtained by land-use regression modeling. The products are being evaluated by focus groups of stakeholders, to assess the usefulness of the COT. Conclusions: The CITI-SENSE COT is facilitating environmental health governance and contributing to future work on time-space-activity exposure classification and dynamic air quality maps. All tools within it are being made available online upon completion of the project.