Ozone and oxygen

Ozone chemistry, oxygen supply, output measurement and the materials that survive it.

Terms (16)

Ozone (O3)Ozone is a gas whose molecules contain three oxygen atoms (O3); the oxygen in air has two (O2). The third atom is loosely bound, which makes ozone both a powerful oxidising agent and an unstable one that reverts to ordinary oxygen.
Medical ozoneMedical ozone is ozone generated from a pure oxygen feed — a medical oxygen cylinder or concentrator — rather than from ambient air. An air feed also produces nitrogen oxides. The phrase describes the feed gas and the gas path, not a regulatory certification.
Oxygen concentratorAn oxygen concentrator draws in room air and passes it through molecular sieve beds that hold back nitrogen, delivering a continuous stream of concentrated oxygen. It stores nothing. In an ozone sauna it supplies the feed gas the ozone generator converts into ozone, and sets the flow rate.
Molecular sieveA molecular sieve is a porous crystalline material, usually a zeolite, with pores of a uniform size that trap some gas molecules and let others pass. In an oxygen concentrator the sieve holds back nitrogen from compressed air, so the gas leaving the bed is mostly oxygen.
Ozone generator / corona dischargeAn ozone generator converts oxygen into ozone at the point of use. The usual method is corona discharge: an alternating high voltage is applied across a gap containing a dielectric barrier, creating a cold plasma that splits O2 molecules, whose fragments then form O3.
Corona discharge versus UV ozone generationThe two common ways to make ozone. Corona discharge uses a high-voltage electrical discharge and produces high concentrations, especially from an oxygen feed. Ultraviolet generation uses a 185 nm lamp to split oxygen and produces much lower concentrations. Therapeutic and industrial equipment uses corona discharge.
Ozone output (mg/h)Ozone output is the mass of ozone a generator produces per unit time, usually milligrams per hour (mg/h). It is a quantity, not a concentration. We rate the generator in the Standard, Deluxe and Red Light ozone steam saunas at 500 mg/h, adjustable across ten levels.
Ozone concentration (ppm)Concentration describes how much ozone is present in a gas mixture, as a ratio. Parts per million (ppm) is the usual unit. It is not the same as output (mg/h), and a concentration inside a sealed cabinet is not comparable to a concentration in the room air people breathe.
O3 disinfection cycleA period in which ozone gas is deliberately circulated through an enclosure with no one inside to reduce microbial contamination on surfaces and in air. Effectiveness depends on ozone concentration multiplied by contact time, on humidity, and on how much organic soil is present.
Singlet oxygen / reactive oxygen species (ROS)Reactive oxygen species are chemically reactive oxygen-containing molecules — superoxide, hydrogen peroxide, the hydroxyl radical and singlet oxygen. Singlet oxygen is ordinary O2 raised to an excited state, not ozone and not a free atom of oxygen. The two terms are often wrongly used as synonyms.
OxidantAn oxidant is a substance that takes electrons from something else, changing it chemically. Ozone is a strong oxidant, which is what makes it useful for disinfecting water and air, and what makes it damaging to lung tissue and to rubber. The same property does both.
Half-lifeHalf-life is the time it takes for half of a quantity of something to disappear. For ozone it is the time for half the gas present to revert to ordinary oxygen. Inside a hot steam sauna we estimate it at about 10 to 20 minutes, and heat, moisture and surfaces all shorten it.
Ozone destructorAn ozone destructor converts residual ozone back into oxygen before the gas is vented, usually over a heated or catalytic bed. It is standard on industrial ozone plant. Our position is that ordinary room ventilation is sufficient for a sauna and a destructor is not justified.
Ozone-resistant materialsMaterials that do not degrade on prolonged contact with ozone. Glass, ceramic, PTFE, PVDF, silicone, fluoroelastomer (Viton/FKM) and 316 stainless steel hold up well. Natural rubber, latex and nylon do not. Everything in an ozone device's gas path has to be chosen this way.
Off-gassingOff-gassing is the release of a gas from a material or an enclosure into the surrounding air. Around an ozone sauna it means residual ozone escaping the cabinet into the treatment room — during a session through the neck opening and door seals, and afterwards when the doors are opened.
Transdermal deliveryTransdermal delivery means administering a substance across the skin rather than by mouth, injection or inhalation. In an ozone sauna the body below the neck is enclosed in a warm, humid, ozone-containing cabinet while the head stays outside, so ozone reaches skin and not the lungs.