The present disclosure relates to methods and system for disinfecting surfaces within an area by forming peracids in a reaction layer in situ on the surfaces to be disinfected. Aqueous compositions comprising peracid reactant compounds, particularly hydrogen peroxide and acetic acid, are sequentially dispersed into the area, preventing peracids from being formed until the two peracid reactant compounds contact each other on the surface to be disinfected. Additionally, aqueous compositions containing peracid reactant compounds can further comprise ethanol to both decrease the surface tension of the droplets and enhance the reactants' biocidal activity. Peracid reactant compounds can be sequentially dispersed as electrostatically-charged droplets, so that droplets of a first aqueous composition containing at least one peracid reactant compound are dispersed with a polarity opposite that of a subsequently-applied second aqueous composition containing at least one peracid reactant compound, driving formation of a peracid on the surface in situ.
