The air quality is a key issue for cities and contributes significantly to the quality of life and housing. In order to secure and steadily increase these, the city of Graz is focusing on comprehensive measures. Including special sensors for monitoring and verification of environmental data and evaluation of the data obtained in an IoT platform. In a first project phase, the Styrian company t-matix solutions developed sensors specifically for the city of Graz, which were installed at critical locations and provide live data to the IoT platform. Including fine particle values, temperature, humidity and air pressure. With the t-matix IoT platform, the city of Graz is now hard- and software-independent, as the platform processes all technology and harmonizes data from different manufacturers. These are evaluated according to the requirements of the city and exported to other systems. In the future, additional weather data and traffic data will be added to the system, creating a data hub that will allow them to react quickly to changes.