Identification of air quality affinity areas in Birmingham, UK

Abstract The paper introduces the concept of air quality affinity areas. A spatio-temporal data set comprising daily sulphur dioxide (SO 2 ) concentrations for a 571-day period and a 17-station network was analysed using principal components and cluster analyses in order to establish whether air quality affinity areas exist for Birmingham, the UK's second largest urban area. Results revealed the existence of four air quality affinity areas which reflect the nature of land use in these areas. The air quality affinity areas are distinct in terms of their magnitude, frequency and timing of onset of SO 2 pollution events. Spatio-temporal patterns of SO 2 concentrations for a 94-day winter period were also investigated. Four spatiotemporal patterns in relation to average winter SO 2 concentrations were identified: region-wide above-average concentrations, region-wide below-average concentrations and two alternating patterns of above- and below-average concentrations for three of the four air quality affinity areas. The conclusion suggests that air quality affinity areas provide a suitable spatial framework for the planning of air quality management zones in large urban areas.