Utilizing a Blockchain for Managing Sensor Metadata in Exposure Health Studies

Commercial Internet of Things (IoT) sensors enable continuous data collection that benefits exposomic studies. The Exposure Health Informatics Ecosystem (EHIE) is one such sensor-based informatics platform for performing multiple simultaneous exposomic studies. It captures data from networks of sensors designed to record air quality in homes of the study’s participants and neighboring areas. In such cases where sensors are continually streaming data, it is crucial to monitor, in real time, the operational status of the network and record possible anomalies. Data collected by these sensors is only useful if it is free of errors. Therefore, maintaining the proper integrity of devices requires the capture of all deployment events that can cause anomalies. Tracking faults by recording system metadata is a difficult task, and we need a mechanism to capture the trajectories of devices within and across studies, systematically capture metadata of deployed version, and assign appropriate provenance to data recorded from each sensor. In this paper, we propose the use of a permissioned blockchain to manage the metadata and connect seemingly unrelated changes to create a trajectory of events that could result in the errors we observe. We implement a preliminary version of our blockchain solution in Hyperledger Fabric to help track errors in such a volatile setup. We also highlight how the properties of blockchain fulfill the essential needs for a metadata management solution needed in our case study.