This paper presents the results of the pioneer case study of the D-NOSES Project (Distributed Network for Odour Sensing, Empowerment and Sustainability) in the Fòrum Area of Barcelona. A new Citizen Science (CS), bottom-up approach was tested to improve the traditional way in which odour pollution is managed, to account for geopositioned and real-time perception of odours in the impact area, using the OdourCollect (OC) App, where a WasteWater Treatment Plant (WWTP), a sludge treatment facility, a waste incinerator, and a Municipal Solid Waste (MSW) treatment plant operate very close to communities. The quadruple helix engagement model was key to involve all actors. After 15 months of engagement, 86 neighbours used the App to report 600 odour observations. The results of the Barcelona pilot paved the way for the remaining D-NOSES pilots (10 in total in Europe, Chile and Uganda) to demonstrate the validity of the methodology (Arias et al., 2018) for the monitoring of the odour impact in affected communities with complex scenarios, as a complement to traditional odour studies. They also pushed the creation of a Spanish standard on the use of CS to monitor odour pollution (Izquierdo et al., 2020), to be published by the end of 2022.