Air pollution constitutes the greatest environmental challenge in Europe (EEA, 2023). In the context of CALLISTO, an EU-funded project, and most specifically its pilot use case "Sensor Journalism", air pollution is studied from a journalistic point of view through an integrated solution comprised of multiple data visualisation tools. One of these tools is CALLISTO's Geospatial Business Intelligence (GeoBI) tool, which provides various visualisations of primarily air quality data and its purpose is to enable journalists identify air quality events and trends to build their stories. The GeoBI tool harnesses data from various sources (e.g., official ground-based monitoring stations, low-cost sensing networks, satellites, social media), providing various visual elements (e.g., figures, maps, pipe graphs, etc.) on historical, near real-time and forecast air quality data, and has the ability to extract and interpret the data in some extent. For example, it takes into consideration the concentrations of the available air pollutants to display an Air Quality Index accompanied with a characterisation of the air quality in a specific location. Further data sources on socio-economic and environmental factors (e.g., roadworks data) are also explored. The files provided here include trends of concentrations of specific air pollutants for the areas of Berlin and Hamburg during 2021 and 2022 (graphs & csv data). The data derive from the official air quality monitoring stations DEBE065 and DEHH008, in Berlin and Hamburg respectively, and are taken from OpenAQ (i.e., one of the data sources feeding the GeoBI tool). Main information regarding the provided files: 1) Berlin AQ trends 2021-2022 Station ID: DEBE065 Location: 52.513379, 13.469294 Year of measurements: 2021, 2022 Pollutants measured: PM2.5, PM10, NO2, CO, O3 2) Hamburg AQ trends 2021-2022 Station ID: DEHH008 Location: 53.564202, 9.967863 Year of measurements: 2021, 2022 Pollutants measured: PM2.5, PM10, NO2, O3, SO2 As the CALLISTO project, and thus the GeoBI tool, progresses, additional graphs related to air quality trends may be generated, which will also be made available to everyone. The CALLISTO project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 101004152.