This dataset consists of a vector layer (based on 1 by 1° grid), of modelled daily surface nitrogen dioxide (NO2, ug m-3). A seasonal average value per grid cell was calculated for the grassland growing season (mid-April to mid-July), for the USA and UK, in 2018. Full details about this dataset can be found at https://doi.org/10.5285/d2524c77-c0b6-4228-a743-ec6f16623d80