This study to develop AQ pollutant datasets for each of the constituent countries of the UK has been commissioned by Defra in order to better inform energy and environmental policy-makers within the Devolved Administrations in their pursuit of objectives set by the Air Quality Strategy for England, Scotland, Wales and Northern Ireland (AQS for ESWNI). These objectives also contribute to the UK’s targets as a whole in terms of meeting both national and international targets on both local and transboundary air pollution