An assembly and method for treating or otherwise improving an atmosphere contained within an enclosed space. The enclosed space can be a container such as a bag or other housing for equipment, food and/or suitable material. Ozone is generated within an atmosphere that is exposed to the material. The generated ozone is mixed with the atmosphere. At least a portion of the generated ozone is then removed from the mixed atmosphere. The assembly and method 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.