An ozone generator, or ozone machine, is a device that converts oxygen from various sources such as ambient air, dry air, or concentrated oxygen into ozone. Ozone generators produce ozone (O₃) by adding energy to oxygen molecules (O₂), which causes the oxygen atoms to part ways and temporarily recombine with other oxygen molecules. The ozone is then used for water disinfection and air purification. Ozone generators can come in small hand-held sizes, all the way up to large-scale industrial models that can produce several hundred grams of ozone each hour. Industrial ozone generators work very similar to ambient air units except they require very clean and very dry air or oxygen and have a corona cell specially designed to generate very high ozone concentrations.

Ozone generators apply an electrical charge to the air that passes through. This splits apart some normal oxygen atoms into unstable single atoms, which bond with other oxygen molecules to form ozone.

Once the ozone is produced it reacts with a pollutant, bacteria, virus, or mold, and breaks it down into less complex (and typically less harmful) molecules through a process called oxidation. Ozone that has not reacted with other molecules will decompose into oxygen over time. Ozonation destroys odors, and disinfects air, water, and other materials. It has even been approved by the USDA and FDA for use on food.