Planning for sustainable cities requires the inclusion of environmental aspects like air quality. Within a planning perspective of 20-30 years, there are various factors influencing future air quality:Worldwide: Climate change may change global background pollution levels and it will affect the atmospheric chemistry.Europe: Many efforts are taken to reduce emissions of air pollutants and climate forcing agents. These efforts will contribute to changes in the levels of air pollution reaching European cities.Locally: City populations will grow. The population growth, together with the design of transportation and energy production systems, influence the city’s own contribution to air pollution.The web-service presented allows end-users in an arbitrary European city to consider these factors impact on air quality. It also includes tools for visualization and standards for easy connection to existing local model systems in the cities.