This work presents the “City Dynamics and Smart Environment” activities of the Smart Ring project, a model for the smart city, based on the integration of sustainable urban transport services and environmental monitoring over a 4–5-km circular path, the “Smart Ring”, around the historical center of l’Aquila (Italy). We describe our pilot experience performed during an experimental on-demand public service electric bus, “SmartBus”, which was equipped with a multi-parametric air quality low-cost gas electrochemical sensor platform, “NASUS IV”. For five days (28–29 August 2014 and 1–3 September 2014), the sensor platform was installed inside the SmartBus and measured air quality gas compounds (nitrogen dioxide, carbon oxide, sulfur dioxide, hydrogen sulfide) during the service. Data were collected and analyzed on the bases of an air quality index, which provided qualitative insights on the air status potentially experienced by the users. The results obtained are in agreement with the synoptic meteorological conditions, the urban background air quality reference measurements and the potential traffic flow variations. Furthermore, they indicated that the air quality status was influenced by the gas component NO2, followed by H2S, SO2 and CO. We discuss the features of our campaign, and we highlight the potential, limitations and key factors to consider for future project designs.