<p>Raising awareness about air pollution and environmental conditions is increasingly important. Across Europe, affordable citizen science environmental and air quality sensors are widely accessible, and their data can be viewed by the public through various web platforms, offering insights into environmental conditions across different regions. Augmented Reality (AR) presents a powerful tool for enabling citizens to monitor local environmental conditions and understand their personal impact, thereby encouraging behavioural change. However, effectively visualising real-time environmental data within a 3D AR space presents significant challenges. To address this, innovative visualisation techniques are essential for presenting environmental data in a clear and engaging way. This paper introduces a framework, a visualisation concept, and a prototype AR application designed to overlay environmental information, such as air quality and traffic data, onto the user’s view. The software framework is capable of easily integrating additional data servers that provide new types of environmental data. These concepts were developed as part of the European project H2020 COMPAIR, which actively involved users in the development process. The application has been tested in various pilot cities and regions and is now available to the public on major app stores. This publication represents an extended version of the conference paper [1]. It contains more technical details on the proposed Air Quality (AQ) visualisation framework, the environmental data servers integrated, a section on geo-localisation and an elaborate presentation of use cases and examples.</p>