Integrating Earth observations in the UK air quality management strategy

Air pollution is the leading environmental risk to human health in the UK and it also impacts crop yields and the natural environment. The current air quality management strategy suffers from data paucity that can be addressed with Earth observations of atmospheric composition. In a collaborative project of academics (Universities of Leicester and Birmingham), local authorities (Birmingham City Council), government agencies (Department for Environment, Food and Rural Affairs), industry (Ricardo), and an innovation incubator (Satellite Applications Catapult), we demonstrate the value in using Earth observations to address air quality data gaps. We apply Ozone Monitoring Instrument (OMI) NO₂ to the post-industrial city Birmingham (population 1.2 million) to estimate long-term (2005-2017) decline in NO_x of 3.9% per year and use OMI NO₂, Infrared Atmospheric Sounding Interferometer (IASI) NH₃ and the GEOS-Chem model to evaluate National Atmospheric Emissions Inventory (NAEI) NO_x and NH₃ emissions. We estimate satellite-derived NO_x emissions of 1.4 ± 0.5 Tg NO₂ that is similar to the NAEI (1.3 Tg NO₂), but there are large spatial discrepancies, notably in cities, along shipping lanes, and at seaports. Satellite-derive NH₃ emissions are almost double (0.42 ± 0.19 Tg) that estimated with the NAEI (0.29 Tg), due to underestimated emissions coincident with crop, pig, horticulture and poultry farming. This lays the groundwork to extend analysis to other cities (London), other pollutants (CO, SO₂, aerosols, NMVOCs), and higher resolution satellite observations (Sentinel-5P).