The Ozone Odor Removal vs. Hydroxyl Debate, Bend OR
Odor removal is a critical part of almost any restoration job. There are a variety of options available from masking agents to foggers to ozone and hydroxyl generators, and so on. Today, there is a rather big inner-industry debate being waged over the benefits and dangers of those latter two options. There is a clear advantage to using machines to eliminate odors from spaces and items rather than simply trying to mask them. During the RIA’s Forensics Restoration Conference in St. Louis last fall, there were people on both sides of the aisle talking about the effectiveness of both technologies – and the downsides.
This time around, odor removal experts are taking the stand to talk odor removal science to help you make an educated decision about which technology is right for your company.
Meet the Experts
David Hart (DH) – Team Ozone – A U.S. Army veteran, David has been involved in the carpet cleaning, and later – restoration industry, since finishing his service in 1991. A problem-solver at heart, David immediately picked up on some ways the duct cleaning process could be improved and in 2007, invented what is known today as the RamAir Duct Cleaning System. He has since invented the OzoGen 10kV High-Output Ozone Generator, and runs Guarantee Cleaning Services, Inc. in Bend, Ore.
Russ McCubbin (RM) – Neutral – Russ has been in the air and water purification equipment manufacturing industry for 25 years. International Ozone Technologies Group, Inc., of which Russ is president, was incorporated in June of 1999 and their first products were the Total Zone Ozone Generators, and a line of “ozonated” oil ointments. International Ozone has been private labeling ozone generators and hydroxyl generators for 12 years and has been named “Vendor of the Year” three times.
Tom McArdle (TM) – Team Hydroxyl – Heavily involved in odor removal education and training throughout the U.S., Tom is the Vice President of the Odorox Hydroxyl Group. Odorox technology was launched in 2008, and in just a few years gained credibility among restoration contractors around the U.S. Two U.S. patents were issued for the technology in 2012.
What is the basic science behind your technology?
DH: Ozone is created when oxygen molecules (O2) are ‘sliced’ in half; the single oxygen atoms (O1) bond with ambient O2 molecules, creating ozone (O3 molecules). Ozone generators also produce ozone using these two principles- UV light and Corona Discharge.
RM: Manmade ozone is produced by two separate processes. One is with UVC ultraviolet light in the 185-nanometer wavelength. The second process is called corona discharge, which produces higher concentrations of ozone than UVC, for faster deodorization. Titan produces hydroxyls by subjecting humidity in the air to UVA light in the 365 to 385 nanometer wavelengths in the presence of a catalyst, usually titanium dioxide. This photocatalyst process splits an H off of H2O leaving OH – hydroxyl and an H.
TM: The Odorox technology was patented because it is the only process able to produce hydroxyl radicals that exit the chamber of the machine to eliminate odors not just in the air, but more importantly, odors that have been adsorbed by contents and structures. This is done by using multiple high energy ultraviolet lights inside the chamber of the hydroxyl machines. It converts water naturally found in the air to hydroxyl radicals, as well as oxy and peroxy- radicals that exit the machine. The hydroxyl radicals that exit the machine are able to eliminate odors, not mask or otherwise cover them up, by disassembling all of the odor molecules including those found deep inside porous materials.
How effective is your respective technology at removing the most common odors restorers see – like smoke, mold, biohazard waste, etc?
DH: The way ozone permanently neutralizes odors is by oxidation. The third oxygen atom in the molecule is loosely bonded to the stable O2 molecule, detaching itself from the O2 when it comes into contact with a receptive odor molecule. This permanently alters the molecular structure of the odor molecule, rendering it odorless. It doesn’t simply cover/mask odors with another odor, it basically removes the odor from existence.
RM: Ozone is faster than hydroxyl at removing odors but must only be used in un-occupied areas. Ozone is great at removing any organic gaseous compound once the source has been removed. Ozone is great for use on mold, mildew, smoke, VOCs, bacteria, virus, etc… Titan hydroxyl generators are not for use as surface microbial kill. They are for airborne microbial kills only, but are great for area and content deodorization.
TM: Hydroxyls are the second strongest oxidant in the world behind atomic fluorine. They are one million times more reactive than ozone, which means they break down a much broader range of odors and pathogens compared to ozone. We have yet to find an odor that Odorox cannot break apart. However, the most difficult project is typically pet urine. This is not because the ammonia is hard to break apart – it’s easy. It’s because the pets were probably there for years and the urine has soaked deep into the flooring which makes it difficult for contractors to fully remove the source. It’s important to remember that disaster-related projects are different and there are always variables to consider when assessing a project. Proper training always helps.
3. What do you say to potential clients concerned about safety of hydroxyl/ozone?
DH: People (and rightly so) are leery of things they don’t understand. There are a few misconceptions out there regarding ozone and its safety.
Nobody has ever died from ozone exposure; however, thousands of people die every year from carbon monoxide poisoning. Carbon monoxide (CO) is toxic; yet we think nothing of standing around our car while it idles, walking down a busy street downtown during rush hour, etc. By simply educating our clients on the safety of ozone, their concerns dissipate.
RM: Ozone is only to be used in unoccupied areas with return to the area at least one hour after the machine has turned off. Ozone can bleach wet materials and damage natural rubber. If a homeowner cannot leave or a store cannot shut down, hydroxyl generators are the way to go.
TM: That is definitely understandable, and part of the reason why Odorox has invested significant time and expenses in safety testing. Examples of tests performed by independent parties include measuring the amount of hydroxyls produced (approx. 2,000,000 per cubic centimeter), a 13-week toxicity study performed on rats under strict FDA GLP guidelines (no adverse effects), the amount of ozone produced so contractors comply with OSHA standards, and testing performed by the FDA which now classifies Odorox as a Class II medical device for use in occupied areas.
What are some major differences you see between these two technologies?
DH: I have to chuckle whenever I think of when a friend of mine who was asked this very question (my friend is one of the world’s leaders in forensic restoration application and education). He said: “The difference, is that ozone works!” To be fair, hydroxyl machines do have their time and place… as people can work in the same room as an operating hydroxyl machine, whereas it’s recommended that the room/building be evacuated while ozone is in use. Despite this minor convenience, hydroxyl takes much longer to work, and isn’t nearly as effective. There’s nearly always an opportunity to run an ozone generator for a few hours, which will often produce considerably better results than what would take a hydroxyl machine days to accomplish.
RM: Both ozone and hydroxyl will remove odors – hydroxyl will just take longer.
TM: Hydroxyls are one million times more reactive than ozone. This means contractors can have the confidence of going to any project knowing that the Odorox will eliminate the odors regardless of what or where they may be – skunk, protein fires, VOCs, biohazard/trauma, fuel oils, curry, etc. Second, they are safe for both people and sensitive materials. It allows odors to be eliminated from all contents without the risk of damaging them – rubber, plastic, electronics, artwork, wet items, etc. Finally, hydroxyls don’t leave behind the residual chemical smell that is common with ozone. An advantage to ozone is that you can produce a very high concentration of ozone as compared to the amount of hydroxyls that can be produced. This means that even though hydroxyls are significantly more reactive than ozone, ozone may eliminate odors faster on certain projects because of the high concentration. For example, in a small area, if ozone takes 24 hours to eliminate the odors, hydroxyls would probably take 36.
Give one raving odor removal story where your technology was used.
DH: My company did a promotion a while back where we offered to treat one home for each local real estate company at no charge, just to show how effective it is. We called it our “Give us your stinkiest home” special. One of the responders to this promotion was a friendly agent who called in desperation, telling me they had a beautiful home that was priced right but absolutely would not sell. The home was previously owned by an older couple who had smoked cigarettes indoors for 20+ years. They cleaned the carpets, scrubbed the walls, and yet the cigarette smoke odor was still so strong it burned my throat within 30 seconds of entering the home. After a single treatment, the home was 100 percent odor free and sold a few weeks afterward.
TM: We have so many great large loss stories, it is tough to pick just one. One that pops out in my mind was a large condo in Manhattan affected by smoke from a fire outside. More than $1 billion dollars in artwork inside the condo was damaged by the smoke. A contractor brought in some hydroxyl machines, and simply running them in the condo restored all the artwork. It was 100 percent effective, and absolutely no risk of damaging the art.
6. Any closing arguments?
DH: Diversification is key in the cleaning industry. It doesn’t take much in the way of financial investment or training to add services like duct cleaning and ozone treatment to your business, and these services are among the most lucrative in the cleaning industry. Instead of contracting or referring it out, offer it yourself and reap the profits!
RM: We see equal sales of ozone vs. hydroxyl equipment – 50/50 split.
TM: The two biggest questions we get are how large of an area does one machine cover and how long it takes to work. Our general guideline is one machine will cover 1,000 – 1,500 square feet with ceiling height up to about 20 feet. Most jobs take three to four days. There are always variables that can change this, but it is important to understand 1,000 – 1,500 square feet is a very accurate number.
To know when the job is done, turn off the machines and go smell porous materials where you know the odor was present – drywall, cabinets, couches, clothes, etc. If the odor is gone, the job is done. If the odor is still there, run the machines longer or move them around.
There you have it. Both sides of the argument, and evidence proving both hydroxyl and ozone work to remove odors during restoration and remediation work. So … which do you choose?
Ozone 101: Using Oxygen Molecules for Odor Removal, Bend, OR
Ozone: noun \’ō,zōn\: a colorless gas with a pungent odor and powerful oxidizing properties, formed from oxygen by electrical discharges or ultraviolet light. It differs from normal oxygen (O2) in having three atoms in its molecule (O3).
In chemistry, we represent elements with letters (for example “O” stands for the element “oxygen”), and the small numbers to the lower-right of the element indicate the number of atoms of that element in the molecule. For example, O2 represents a molecule that consists of two oxygen atoms, which is the stable form of “regular” oxygen. O3 represents a molecule that consists of three oxygen atoms, which is the unstable form of oxygen called ozone.
Ozone has existed on Earth for as long as oxygen has been here- about 500 million years. It has existed in our universe for billions of years. Wherever oxygen comes into contact with an electric arc, such as lightning and/or a particular wavelength of ultraviolet rays, like those from the sun around which the planet orbits, ozone will be created.
How is ozone generated?
During an electrical storm, bolts of lightning in the atmosphere rip oxygen molecules apart, leaving single oxygen atoms in their wake. These single atoms quickly bond with surrounding O2 molecules, creating O3, or ozone.
This is why the air smells so fresh right after a lightning storm. Lightning is nature’s air purifier.
The ozone layer in the lower stratosphere is also generated by molecular fission and fusion, but by the sun’s short wave ultraviolet rays rather than by electricity. Coincidentally, it’s this ozone layer- created by short UV waves, that protects life on our planet from the longer UV waves within the spectrum.
Ozone generators manufacture ozone by applying either of these same two principles:
1. Corona Discharge
Ozone generators that utilize the electric arc method of generating ozone are referred to as corona discharge ozone generators. High voltage (2,000 volts and up) is passed through a dielectric material (material that transmits electrical force without conduction), while being fed and cooled by ambient air supplied by a fan located at the rear of the unit. Ambient air is made up of 78.08% nitrogen, 20.95% oxygen, .93% argon, the remaining .04% consisting of trace amounts of other gasses.
This sustained electric arc is what severs the O2 molecules, resulting in the manufacture of ozone.
2. Ultraviolet Light
Waves of ultraviolet (UV) light are what ‘slice’ O2 molecules in half in UV ozone generators. UV bulbs are mounted inside the generator which emit certain wavelengths of ultraviolet light which, in turn, separate the atoms of passing O2 molecules. This is how our sun creates and maintains the protective ozone layer between the troposphere and stratosphere.
UV is much less effective at generating ozone than corona discharge. Generators of this type typically have a much lower ozone output as a result.
How does ozone destroy odors?
Ozone reacts with odor molecules by transferring the “extra” oxygen atom of the ozone molecule to the odor molecule, changing its composition so it no longer has the same chemical makeup. This chemical reaction is called oxidation.
In a nutshell, through the oxidation process, what was formerly an odor-causing molecule is now an entirely different compound, and therefore does not possess the odor of its preceding form. A simple example of this molecular restructuring is the addition of an oxygen atom to a molecule of H2O to form H2O2 (which is the conversion of water to hydrogen peroxide).
To compare the difference between odor treatment using deodorizers and ozone, I often use the following analogy with my students. Pretend we have two foul-smelling odor molecules, and think of them as two bad guys. Let’s treat the first bad guy with a spray-on deodorizer. This can be represented by locking him in a jail cell so he can’t affect anybody or anything. He’s harmless, but “underneath it all”, he is still a bad guy. If the cell in which he is locked falls apart or wears out (or if his sentence time runs out), he is released and can again be an actively bad guy… or in our case, a stinky odor molecule.
Now let’s take the second bad guy and treat him with ozone. During the oxidation process, his very molecular structure is altered; he is no longer the same thing. This can be represented by waving a magic wand and “poof- he’s a rabbit!” Since the bad guy has been turned into something completely different/harmless, he can no longer be a bad guy- for he is now a rabbit, permanently, or in our case, a molecule without an unpleasant odor.
Is Ozone Dangerous?
The most important thing to remember when generating ozone in a space is to evacuate the premises during the treatment. This includes the removal of pets, and in the case of high levels generated over a period of several hours, removal of houseplants is suggested. It’s a good idea to post “Do Not Enter- Ozone Area” (or similar message) signs on all entrances of a space as well.
After the treatment time is complete, either enough time should pass for the ozone to revert to oxygen (O2), or the space should be circulated with fresh air before people and animals are reintroduced.
Ozone has a relatively short half-life of approximately 30 minutes. For example, a half hour after the generator turns off, an ozone level of 10ppm (10 parts per million) will be 5ppm, and a half hour after that, it will be 2.5ppm, and so on. This quick degradation process is the result of the weak bond holding the third oxygen atom to the molecule.
There is a lot of conflicting information out there regarding how safe ozone use is in the restoration industry. While prolonged exposure even in light concentrations can be irritating to tissue, especially the lungs, using the proper precautions can help everyone avoid any side effects at all.
By way of comparison, carbon monoxide (CO) is considerably more dangerous, being responsible for 2,500 deaths annually, yet we think nothing of walking down the street in heavy traffic, alongside countless huge carbon monoxide generators (cars).
And here’s one of the most beautiful things about using ozone in the restoration industry- the only residue resulting from the generation of ozone is oxygen (O2).When used properly and a few simple rules are followed, ozone can be a safe and effective tool.
WORKING WITH DEAD BODIES
We constantly get calls from the disaster restoration companies in our area wanting to hire us to clean and sanitize the duct systems in homes and businesses following a fire, flood or other catastrophe.
I always recommend networking with entities such as building contractors, property management companies, real-estate agents and HVAC installers, as long as the companies with whom you’re networking are upstanding representations of their industry.
Remember: You’re a reflection of them, as they are of you.
Disaster restoration companies are some of my favorites, as they constantly stimulate us with something different from the norm, and the revenue generated by performing work for them is usually maximized.
So when our phone rang one recent morning and we were asked to perform a duct cleaning and sanitizing in a home, it started out pretty routinely.
After the address of the residence was given and a cleaning date selected, our receptionist asked for the nature of the disaster.
The restoration representative paused, lowered her voice and replied, “A human corpse was discovered in the home two weeks after expiring.”
Now, we’ve handled duct cleaning in homes where people have died before, but this was a little different. Usually when a person expires in their home, the body is quickly removed, and it’s not too difficult to clean.
In this case, not only had two weeks passed before the body was removed, but the weather had been in the mid-90s, and there was no air conditioning in the home.
Fortunately for us, duct cleaners are usually one of the last ones to perform our services in disaster cleanup situations, so the rest of the home had already been cleaned and was in pretty good shape when we got there.
Although there still was an unmistakable odor present — an odor which is difficult to describe. If you’ve experienced this odor before, you know what I mean, and you’ll never forget it.
Just to be on the safe side, wanting to be sure everything was done “to code,” I called and spoke with a representative with the Environmental Protection Agency (EPA). Additionally, being a member of the National Air Duct Cleaner’s Association (NADCA), I called and spoke with one of their experts.
In a nutshell, it was basically a matter of making sure every bit of the ductwork was cleaned and sanitized using equipment and antimicrobials that met the standards for such a level of restoration.
The first step was to take a look at the duct system to see with what we were dealing with:
- What type of ducting was it, and how porous was it?
- What was the inside the furnace — i.e., did it have fiberglass lining?
Cleaning the ducts
By removing the register covers and looking and feeling down the ducts, we could tell they were made of typical plastic flex, so the porosity was not a factor; however, they still needed to be deep-cleaned and sanitized.
We performed a thorough cleaning with an air whip and skipper ball, removing all the dust and debris adhering to the sides of the ducts.
As with nearly all homes that have not had their ducts cleaned recently, copious amounts of sheetrock dust, sawdust and household dust came pouring out into our vacuum box and HEPA vacuum unit. We cleaned the ducts one at a time, first agitating the duct walls with the air whip, then blasting them with the compressed, air-powered skipper ball, scouring the sides with 100+ psi of targeted air.
Construction debris in the form of chunks of wood, sheetrock, nails and discarded sandpaper were then vacuumed out by running the vacuum hose through each duct.
There’s nearly always some “interesting items” removed during this part of the process. In this case: An empty yogurt container (probably discarded by a construction worker 23 years prior); a McDonald’s Big Mac container, which still had some cheese stuck to the inside that was now dehydrated and petrified by two decades’ worth of warm-air movement over it; some marbles and loose change; a tennis ball that likely fell in and rolled down during a game of “fetch” and a handful of toys ranging from Barbie accessories to tabletop game pieces.
Cleaning the furnace
Once we were sure the return and supply ducts were cleaned, we moved our attention to the furnace.
Removing the access doors, we found that indeed there was a fiberglass lining, as is the case for most furnaces, which is quite porous and very successful at trapping odors. We needed to be especially effective at removing the dust and debris from the furnace and fiberglass lining, as the dust itself works like an “odor sponge” and can be very odoriferous.
The thin layer of dust covering the furnace interior was proportionate to that which was on the duct walls, and was blown off rather easily.
Sanitizing the system
After making sure the furnace was completely devoid of all dust and debris, we applied an antimicrobial/ odor- neutralizing sanitizer to it by removing the application hose from the SaniJet and fogging the furnace interior directly.
We then disinfected the ducts themselves, fogging the sanitizer directly to the duct walls by running the SaniJet hose through each duct via each duct opening and blasting them with the sanitizing fog.
I believe it’s very poor practice to treat odors with other aromas, such as “spring fresh this” or “flowery that.”
Covering odors is not getting rid of the problem; it’s just adding pleasant odor on top of an unpleasant one. To me, this is tantamount to, rather than taking a shower, simply slathering oneself with deodorant and body spray every day.
Proper duct sanitizing is a good follow-up to every duct cleaning, but in a restoration situation such as this, it’s absolutely crucial.
Finishing with ozone
As the final step to ensure that any and all odor-producing molecules had been completely eradicated, we turned the furnace system on and placed an industrial-grade ozone generator on an intermittent 48 hour setting at the entrance of the return duct.
While the ozone generator is operating, each entrance to the dwelling must be clearly marked with “Ozone — Do Not Enter” signs, as it’s a biologically hazardous gas while in its active form.
The beauty of ozone is two-fold:
- It is a very powerful sanitizer and odor neutralizer, which destroys fungus, bacteria, mold, etc.
- After it’s generated, its half-life is very short, converting back to oxygen in a short amount of time and leaving no residue or toxic trace.
I was eager to return to the job site after the ozone generators had completed their cycle and all the ozone had a chance to form back into oxygen. I wanted to give the home a “sniff test” to see for myself how effective our process was at ridding the building of odors.
As I walked through, it was very satisfying to smell absolutely nothing.
The restoration company was thrilled with the results, even going so far as to write us a thank you letter for our efforts.
David W. Hart, founder and CEO of RamAir International, is a 24-year veteran in the carpet and duct cleaning industry. He invented the RamAir ClearView Duct Cleaning System, which is now available for purchase in more than 500 locations in five countries. He also owns and runs Guarantee Cleaning Services Inc. in Bend, OR. Visit his websites at www.ramair.co and www.guaranteecleaning.com.