Understanding Ozone For Scent Elimination
May 26, 2011
What air-delivered decontaminant is 3,000 times more potent than chlorine, annihilates most any smelly organic compound it contacts, and can render your clothes, gear or accessories virtually scent free? Concentrated ozone! Ozone treatments have so profoundly changed my previously laborious and time-intensive approach to preparing for a scent-free hunt that when not available, I feel seriously compromised. That best describes my experience with ozone generators (OGs), and my addiction to their compelling utility and convenience. I firmly believe this technology will revolutionize the way we wage war in limiting our scent, especially when used as part of a systematic approach to minimizing our overall scent signature.
How Ozone Generators Work
My introduction to OGs was through Moxy Technologies (not currently commercially available), but all OGs produce ozone in one of two ways -- corona discharge (most common) or ultra violet -- with varying levels of ozone output measured in milligrams per hour (mg/h). *Corona discharge creates ozone by applying high voltage to a metallic grid placed between two dielectrics. The high voltage passes through the dielectric to a grounded screen/plate, and in the process creates ozone from oxygen pulled into the unit from ambient air. Ultra-violet (UV) light creates ozone when a wavelength at 254 nanometers hits an oxygen atom. Both processes split oxygen molecules into single oxygen atoms (O). These atoms combine with another oxygen molecule (O2) to form ozone (O3). The unit then disperses the O3 with a fan or air pump to a port or hose. The O3 that is emitted is a predatory oxidizing molecule that destroys the organic scent-containing molecules it contacts, similar to the oxidizing effects of chlorine bleach, but in a powerful airborne form. After oxidizing a contaminant, O3 reverts back to O2 (*To learn more, visit FAQ at www.ozonesolutions.com).
Commercial units capable of destroying mold, mildew, fungus, viruses, and bacteria in large spaces can provide varying output up to 10,000 mg/h from ambient air as a source (a pure oxygen source would create a higher concentration of ozone). The more economical hunting-oriented models typically generate ozone in the 1 to 400 mg/h range for use in confined spaces like sealed garment bags, storage containers, a closet, or small room -- or to act as an intermediary scent reduction measure by impacting scent molecules between you and your prey (more on that later). An OG's potential output is adversely impacted by high temperature and humidity; most require operating the unit in an environment of less than 60% humidity (to prevent internal component damage and maximize output), easily accomplished with a dehumidifier or air conditioner. Overall output is important, but to a degree. Higher mg/h units treat gear faster and offer more potential uses, from killing mold and mildew in your basement to sanitizing large amounts of clothing and gear quickly like an outfitter might need. However, given enough time for exposure and confining the treatment area to improve concentration, even a unit with low output can provide a benefit.
If you employ a pee bottle when hunting, a quick and effective demonstration of ozone's amazing cleansing power is easy to experience: empty your bottle of all urine after a hunt, treat the bottle's interior with ozone for five minutes, then take a deep whiff. You will be a believer. You can perform a similar test with foul socks after a long hike. The science is proven, being employed in a wide array of industries from healthcare (to eliminate biological contaminants in surgical rooms), to rental cars (smoke, mold, fungus, and other organic smells), to sports teams (bacterial infection prevention), and even municipal water treatment.
My ozone epiphany occurred one warm morning in early season after cleaning a deer. I had managed to thoroughly coat my pants, shirtsleeves, and rubber boots in blood, and the rest of my clothes in heavy sweat during the long, hot drag back to my truck. This putrid combination of contaminates was literally cleansed from my duds by a 35-minute treatment of ozone in a sealed garment bag while I ate lunch. After treatment I could see the bloodstains, but I couldn't smell them, and the garments had a fragrance similar to the "fresh outdoors" smell you detect after a spring thunderstorm, which is one way nature creates ozone. It's a natural part of the air around us, not to be confused with the smog it's often associated with.
Many OGs manufactured for hunting purposes can operate on AC or DC power, and work wonderfully for decontaminating the mysterious odors in your car as well. When I don't have a garment bag handy, that's precisely how I treat all my gear in the field: roll up the windows, lay all my gear (pack, shooting glove, clothes, hat, boots, bow) out on the seats and turn the unit on to "wash" it free of smell. If you turn your AC on and put it on re-circulate, you can even kill the smell of mold and mildew in the AC system, provided you leave the unit on long enough. Low output ozone can further be used to decontaminate your hair, scalp, and feet by blowing it over them for a few minutes -- while you hold your breath.
How long does ozone last? Not long; maybe a couple hours under very favorable conditions. Ozone is very unstable and has a half-life of approximately 30 minutes before it quickly reverts back to the harmless O2 we breathe. You can start out on every hunt completely sanitized, but if you sweat or get other contaminants on you after treatment, ozone's residual effect is minimal. Use of antimicrobial and carbon-containing garments can further enhance your total scent-control arsenal, along with all your other countermeasures. Keep in mind that in order to work properly, ozone MUST come in contact with the contaminants on your clothes and gear. You can't just throw your clothes folded on top of one another in a plastic bin and expect good results. The ozone needs to freely circulate and contact all surfaces, and being heavier than air, it should be dispersed high in the treatment area.
A few manufacturers of OGs advocate the technology is best employed by taking it directly in the field with you -- foregoing advance treatment of your gear -- and instead using it to impact your downwind scent stream by having small concentrations of ozone intermingle and impact your dispersed scent cone. Ozonics' Dennis Fink put it this way: "We don't know exactly what part of our scent signature animals react to, and while you do need high concentrations of ozone to kill certain organic contaminants embedded in clothes for example, what we are finding out is relatively small amounts of ozone in an open air environment can meaningfully decrease an animal's ability to detect you. We feel that treating the air stream between you and your prey is a much more advantageous application of the technology." I haven't used ozone in this application, but those who do, like Jason Zins, a store manager at Scheel's, swear by it when used that way. "I can't imagine hunting from a treestand without it ever again," Zins said, relating his experience with an Ozonics unit hung above him.
Is it safe? A few words of caution: Ozone is a lung irritant, and in my opinion, you should never breathe it in a confined space, even at low output levels. How about in a tree above you? Different people react differently to all sorts of elements in different concentrations, from salt to car exhaust; I'm going to try it this fall, but the first few times I'm going to ensure it's only on days with some measurable wind. Even though ozone is present in the lower atmosphere, we breathe in concentrations from .001 to .01 parts per million (ppm), it is usually at very trace amounts. An OG's absolute safest use is to treat your clothes and gear in a confined, unoccupied space.
The National Institute of Occupational Safety and Health recommends an upper limit of .10 ppm. The EPA's National Ambient Air Quality Standard for ozone is a maximum eight-hour average outdoor concentration of .08 ppm. Some of the more powerful generators can quickly exceed that level if you're in a confined space, like a blind, for a period of time. Some low-output ozone units may not exceed these ppm thresholds in a blind with air current. To be truly safe, if you really want to use ozone for a blind application, get it above you out of the blind and let it interact with your scent stream as it drifts downwind. The reason many OGs, namely the more versatile industrial-oriented models, offer greater and variable output power is for their "shocking" ability to destroy mold, mildew, fungus, and other stubborn micro-organisms in unoccupied rooms, cars, or other spaces. And while ozone does an unbelievable job of killing pet odors in everything from dog beds to hamster cages, DO NOT expose your pet or even plants, just to be safe.
Ozone will shorten the life of rubber, like that found in boots, washers, and seals, through concentrated oxidization. However, I've used it regularly on rubber boots for three years and have seen no material degradation. Natural rubber, small washers, O-rings, and the like may be quite susceptible to ozone's amazing oxidizing power -- and a lot quicker than you might think.
The way I choose to employ it, OG's benefits far outweigh the negatives. I avoid shortening the life of my favorite clothes through repeated washings after every hunt; it's far faster than washing and drying; you can treat items like packs, boots, releases, and other gear very conveniently; and I don't need to bring lots of clothes on hunts because I can re-treat my gear anywhere there is AC or DC power.