Nano and micro-sensors: Real time monitoring for the smart and sustainable city

With sensors becoming smaller, more accurate and networked, the knowledge about our environment in urban studies can be enriched; thanks to the availability of diffused fine-grained and real-time information layers, the smart city concept can be enhanced as the sustainable city. For example, the use of electrochemical sensors for monitoring urban air quality allows the deployment of multi-scale high-density air quality sensor networks at fine spatial and temporal scales, and in both static and mobile configurations, pushing the boundary of traditional environmental and urban studies. In addition, deploying diffuse biosensors to measure qualitatively and quantitatively specific behavior from communities (i.e. biomarkers) might foster a completely new approach to the study of cities and their urban environment, people, and technology. The paper will therefore present a systematic review of previous studies on micro and nano-sensors applied to the smart city concept and projects, stressing challenges and positive outcomes. Monitoring for surveillance, urban management, knowledge support for assessment, and decision making processes are the main features potentially enhanced by the use of sensors for the smart and sustainable city, and starting from the different experiences analyzed, the paper will discuss how sensors are currently changing the way cities are studied and managed.