This dataset is from the Northern Ireland (NI) DELTA® Gas and Aerosol Monitoring Network, and consists of monthly atmospheric concentrations of inorganic, water-soluble, reactive gases and aerosols measured with the UKCEH DELTA® method at 4 sites across NI for the years 2019 to 2020. • Gases: ammonia (NH3), nitric acid (HNO3), sulphur dioxide (SO2) • Aerosols: ammonium (NH4+), nitrate (NO3-), sulphate (SO42-), chloride (Cl-), sodium (Na+), calcium (Ca2+), Magnesium (Mg2+) The network is operated jointly by Agri-Food and Biosciences Institute (AFBI) and the UK Centre for Ecology & Hydrology (UKCEH), and funded by the Department of Agriculture, Environment and Rural Affairs (DAERA), Northern Ireland. Full details about this dataset can be found at https://doi.org/10.5285/55ad7cf8-fc40-4b8a-9d35-ce970a915ff6
