An apparatus and method for sanitizing, decontaminating, deodorizing, conditioning, drying, treating, cleaning, modifying and/or otherwise improving an atmosphere within a container. The container can be a bag or other housing for equipment, food and/or suitable material. Ozone is generated within an atmosphere that is exposed to the materials. The generated ozone is mixed with the atmosphere. At least a portion of the generated ozone is then removed from the mixed atmosphere. The apparatus and method of this invention can be used to treat contaminated sports equipment and the like, as well as to treat food storage atmospheres, such as those exposed to fresh fruits and vegetables.