Tobacco smoke, fire damage, mold and mildew all leave their mark. The memory stays in carpets, ceilings, air ducts, walls, even clothing. These smells are not easy to get rid of. Scented candles and air fresheners work for a moment, but they only mask the odor for a little while. Air purifiers clean dust, pollen and other particles from the air, but leave odor causing bacteria and other microbes behind. Deep cleaning with bleach or other harsh chemicals or odor removers is time consuming and only works on some smells.
Hotels, food processing plants and disaster clean-up crews use ozone generators to eliminate odors. Professional residential cleaners sometimes offer ozone purification as part of their services. Some manufacturers sell ozone generators for personal, residential use. Ozone generators produce electro-charged ozone that attaches to odor causing microbes. This changes the molecular structure of the odor particles causing them to break apart and fall to the ground. Ozone generators penetrate carpets, walls, window treatments, light fixtures and air ducts with ozone. Since ozone kills the bacteria that cause nasty stenches, the smell does not return. Once deodorized the area smells fresh and clean, much like the scent after a good rain shower.
This all sounds well and good, but ozone is dangerous to breathe in large quantities. While the Food and Drug Administration (FDA) does not regulate ozone generators, there are federal standards of how much ozone is safe to inhale, ranging between 0.05ppm 0.10ppm. Some states, such as California, have even lower thresholds. Most ozone generators output ozone in quantities several times the recognized safety amounts. It usually takes up to 60 minutes after the generator cycle ends for the ozone to neutralize into oxygen that is safe to breathe. Breathing even minimal amounts of ozone can be toxic. Lung irritation, ozone poisoning, lung scarring, cancer and death are all health risks associated with breathing ozone. The EPA website lists twenty-six different scientific research articles describing the dangers of ozone inhalation and the use of ozone as an air purifier. This research has formed the foundation of the EPA recommendation against the use of ozone generators.