Abstract
<title>Abstract</title> <p>Air pollution, meteorological conditions and traffic activity are interrelated factors affecting urban air quality. We present a spatio-temporal dataset built from the Open Data Portal of the City Council of Madrid, Spain. The dataset integrates air quality measurements available since 2001, meteorological measurements available since 2019 and traffic measurements available since 2015. The temporal intersection of the three sources spans six years, providing hourly observations that combine environmental and mobility-related information for the same urban area. Records are aligned at air quality monitoring station locations and include 14 air quality pollutants, seven meteorological parameters and traffic variables derived from more than 5,000 traffic sensors. By bringing these heterogeneous public data sources into a common temporal resolution and station-centred structure, the dataset may support studies of urban air quality, exposure assessment, traffic-related pollution, environmental monitoring and spatio-temporal modelling in dense urban settings.</p>