Outpatient clinics, shops, restaurants, hotel rooms, waiting rooms are all places with a high flow of people. These spaces are those most exposed to the risk of contamination, especially in emergency situations. Sanitizing with ozone has many advantages: it is economical, respects the environment, can be carried out daily and independently. Ozone is very effective for removing chemical or biological contaminants and odors such as smoke. Sanitization requires an ozone generator suitable for the volume and characteristics of the environments to be treated. Usually a high concentration of ozone is introduced for short periods. During the cycle there must be no people or animals inside the room; for this the operation is performed during the night. “Maintenance” treatments can be carried out with people staying only in the case of minimum ozone dosage. Ozone is an unstable gas: it has a short life and tends to return naturally to the oxygen state.