Foulds, AmyKhan, M. Anwar H.Shallcross, Dudley E.2022-02-172022-02-172021Foulds, A. et al. (2021). Abundance of no3 derived organo-nitrates and their importance in the atmosphere. Atmosphere, 12(11), 1381. https://doi.org/10.3390/ atmos121113812073-4433https://doi.org/10.3390/ atmos12111381http://hdl.handle.net/10566/7280The chemistry of the nitrate radical and its contribution to organo-nitrate formation in the troposphere has been investigated using a mesoscale 3-D chemistry and transport model, WRFChem-CRI. The model-measurement comparisons of NO2 , ozone and night-time N2O5 mixing ratios show good agreement supporting the model’s ability to represent nitrate (NO3 ) chemistry reasonably. Thirty-nine organo-nitrates in the model are formed exclusively either from the reaction of RO2 with NO or by the reaction of NO3 with alkenes. Temporal analysis highlighted a significant contribution of NO3 -derived organo-nitrates, even during daylight hours. Night-time NO3 -derived organo-nitrates were found to be 3-fold higher than that in the daytime. The reactivity of daytime NO3 could be more competitive than previously thought, with losses due to reaction with VOCs (and subsequent organo-nitrate formation) likely to be just as important as photolysis. This has highlighted the significance of NO3 in daytime organo-nitrate formation, with potential implications for air quality, climate and human health. Estimated atmospheric lifetimes of organo-nitrates showed that the organo-nitrates act as NOx reservoirs, with particularly short-lived species impacting on air quality as contributors to downwind ozone formation.enOrgano-nitratesAtmospheric lifetimeSecondary organic aerosolAir qualityChemistryArticle