NOVELTY - The method comprises generating a gas comprising purified hydrogen peroxide gas (PHPG) that is free of associated water in the form of water in solution or water molecules bonded by covalence, van der Waals forces or london forces, ozone, plasma species and/or organic species by exposing a metal or metal oxide catalyst (3) to ultraviolet light (4) in the presence of humid purified ambient air under conditions, and directing the PHPG into the environment such that the hydrogen peroxide gas acts to provide microbial control and/or disinfection/remediation in the environment.    USE - The method is useful for microbial control and/or disinfection/remediation of an environment including indoor air treatment, water purifier, mold eliminator, bacteria eliminator, and virus eliminator (claimed), where the microbes are molds, mildew, spores, and organic and inorganic pollutants.    ADVANTAGE - The method ensures safe and effective control and/or disinfection/remediation of the microbes in the environment thus preventing the spread of Pandemic Flu, controlling nosocomial infections and reducing the transmission of common illnesses.    DETAILED DESCRIPTION - The method comprises generating a gas comprising purified hydrogen peroxide gas (PHPG) that is free of associated water in the form of water in solution or water molecules bonded by covalence, van der Waals forces or london forces, ozone, plasma species and/or organic species by exposing a metal or metal oxide catalyst (3) to ultraviolet light (4) in the presence of humid purified ambient air under conditions, and directing the PHPG into the environment such that the hydrogen peroxide gas acts to provide microbial control and/or disinfection/remediation in the environment both on surfaces and in the air. The generated PHPG is electrostatically attracted to complimentary positively and negatively charged structures and/or sites on microbes for raising its efficacy in microbial control and/or disinfection/remediation as compared to hydrated hydrogen peroxide or ozone. The PHPG produced is 0.005-0.40 ppm in concentration. The PHPG produced is actively regulated to a desired concentration by balancing feed air between untreated air and fractional recirculation of air already treated with PHPG. The percent humidity of the air is 5-99%. The PHPG production also results in the removal of ozone and volatile organic compounds (VOCs) from the ambient air by direct chemical reaction of these species with PHPG. The removal of the PHPG comprises reacting the PHPG with ozone to produce oxygen and water, and reacting PHPG with VOCs to produce carbon dioxide and water. The metal or metal oxide catalyst is exposed to ultraviolet light at a wavelength of 255-380 nm. An INDEPENDENT CLAIM is included for a diffuser device for producing purified hydrogen peroxide gas.    DESCRIPTION OF DRAWING(S) - The diagram shows a cross-section of a diffuser device.    Reflector (1)    Diffuser shell (3) Metal oxide catalyst (2)    Ultraviolet source. (4)