currently, the depiction of urban air quality at boundary layer scale uses modelled climatic and land cover data. However, such models are difficult to verify, and only low to moderate accuracy may be achieved due to the complexity of the input data required and the reliance on assumptions about dispersion patterns.The provision of comprehensive air quality data to urban residents in city districts, at a level of detail commensurate with other Location-Based Service (LBS) which are time and place sensitive, has therefore not been possible.