A method for disinfecting a volume or surfaces bounding a volume comprisingnebulising a solution comprising a sterilizing agent in a solvent having alower boiling point than the sterilizing agent, for example ultrasonicnebulization of aqueous hydrogen peroxide, to form a nebulant. The nebulant issubjected to energy of a kind and for a duration sufficient to vaporizesolvent in preference to sterilizing agent, eg heating element means, infrared, laser, microwave, RF or other radiation generating means； inductionheating means； heat exchanger means； conduction means； convection means； ormechanical energy transfer means to increase the concentration of the agent inthe nebulant particles. Vaporized solvent is removed from the gas stream at orabove atmospheric pressure and, if necessary, the nebulant is cooled to below7O0C. The volume or surfaces are exposed to the nebulant for a time sufficientto sterilize said volume or surfaces. Also, apparatus for carrying out themethod.
