High time-resolution measurements of electron density in the lower ionosphere are made by the EISCAT incoherent scatter radars. We analyse a series of localised electron precipitation events using the detailed time-dependent Sodankylä Ion Chemistry (SIC) model. We model the time development of the effective recombination coefficient in order to analyse the response of ion and neutral composition to the precipitation. Special attention is paid to the variations of the concentrations of the molecular ions O₂⁺ and NO⁺.