The present invention relates to a method of disinfecting a given facility or equipment such as a room, apparatus, container or vehicle and a mobile disinfection unit (1) for use in the method. The method comprises a treatment step arranged for adding ozone and steam/water droplets into the air of the facility or equipment, means (25) for continuously detecting the ozone concentration in the facility or equipment, and a removal step arranged for removing residual ozone and any contaminates from the facility or equipment when a predefined ozone concentration has been reached and maintained for a specific time interval.
