A method of decontaminating a room or space, comprising the steps of: a) providing a cold-mist decontamination device capable of generating an atomized mist comprised of a decontaminant and water, from a liquid decontamination solution having a known concentration of said decontaminant therein, said decontamination device having a controller having an internal processor controlling the operation of said decontamination device, wherein said decontaminant is hydrogen peroxide; b) determining a volume of the room or space to be decontaminated and measuring temperature and humidity in said room or space; c) inputting into said internal processor parameters of said room or space and the concentration of the decontaminant in said decontamination solution, wherein said parameters regard the temperature, the humidity, and the volume of said room or space; d) determining the maximum amount of said decontamination solution that can be introduced into said room or space in atomized form without condensing said decontaminant on surfaces within said room or space and determining the actual amount of decontaminant in said maximum amount of decontamination solution; e) determining a time period necessary to effect a predetermined level of decontamination in said room or space based upon the actual amount of decontaminant that can be introduced into said room or space based upon empirical data stored within said controller; f) operating said decontamination unit to introduce an atomized mist of said decontamination solution into said room or space; g) terminating the production of the atomized mist of the decontamination solution once the maximum amount has been introduced into said room or space; and h) providing an indication when said time period has elapsed as measured from the time production of the atomized mist had ceased. a) providing a cold-mist decontamination device capable of generating an atomized mist comprised of a decontaminant and water, from a liquid decontamination solution having a known concentration of said decontaminant therein, said decontamination device having a controller having an internal processor controlling the operation of said decontamination device, wherein said decontaminant is hydrogen peroxide; b) determining a volume of the room or space to be decontaminated and measuring temperature and humidity in said room or space; c) inputting into said internal processor parameters of said room or space and the concentration of the decontaminant in said decontamination solution, wherein said parameters regard the temperature, the humidity, and the volume of said room or space; d) determining the maximum amount of said decontamination solution that can be introduced into said room or space in atomized form without condensing said decontaminant on surfaces within said room or space and determining the actual amount of decontaminant in said maximum amount of decontamination solution; e) determining a time period necessary to effect a predetermined level of decontamination in said room or space based upon the actual amount of decontaminant that can be introduced into said room or space based upon empirical data stored within said controller; f) operating said decontamination unit to introduce an atomized mist of said decontamination solution into said room or space; g) terminating the production of the atomized mist of the decontamination solution once the maximum amount has been introduced into said room or space; and h) providing an indication when said time period has elapsed as measured from the time production of the atomized mist had ceased.