PCO RCI-Buyer beware
Some interesting information from
Study Finds RCI Devices Increase Indoor Ozone and Are Ineffective
By Jim Rosenthal, 2/10/2007
This study shows that the RCI (radiant catalytic ionization) Air Cleaning Devices produce significant levels of ozone and are relatively ineffective at particle removal.
Researchers at the University of Cincinnati have found that the RCI "air cleaning device" produces a significant amount of ozone and is relatively ineffective at removing particles from the air. Their study written by Sergey Grinshpun, et. al. and entitled "Control of Aerosol Contaminants in Indoor Air" was published in Environmental Science and Technology, Vol. 41, No. 2, 2007.
The product tested was supplied by Ecoquest and it combines unipolar ion emissions and photocatalytic oxidation promoted by the "radiant catalytic ionization" (RCI) technique. The researchers found that when an RCI device was placed in a 24.3 cubic meter chamber (10'X11'X8') it increased the ozone level in the chamber from 6 ppb to over 50 ppb in just 35 minutes. The FDA has established 50 ppb of ozone as the maximum allowable level in a room with an ozone generating medical device. However, currently no federal agency regulates the ozone allowed for household air cleaning devices. The researchers also found that the RCI device pushed the level of ozone in a "bathroom" sized chamber over the 50 ppb in just 5 minutes. This would indicate that the "radiant catalytic ionization" (RCI) technology has the potential to create unsafe levels of ozone in small, poorly ventilated rooms. The researchers point out that the RCI devices "were tested in non-ventilated chambers (no air exchange) as it is known that portable air cleaners are perceived to be primarily beneficial in poorly ventilated spaces."
The manufacturers and marketers of the RCI product claim that the device is effective at removing particles from the air. However, when the researchers tested the particle removal efficiency of the device, they found that after 120 minutes of continuous operation in the 10'X11'X8' chamber it was less effective than a standard pleated filter in removing 2 micron sized particles. The filter was in a system set to provide just 2.5 air exchanges per hour.
Using NACL particles of various sizes as the challenge particles the study showed that the RCI device had a Clean Air Delivery Rate (CADR) of 32.4 cfm on particles at .041 microns, a CADR of 32.1 cfm on particles at 0.13 microns, a CADR of 29.4 on 0.499 micron particles and a CADR of 23.5 on particles of 2 microns. Most homes have a higher air infiltration rate than this. In other words, in a ventilated space the net effect of running the RCI device would be zero on these particle sizes.
The researchers compared the particle removal performance of the RCI device with a MERV 8 pleated filter. The MERV 8 pleated filter is tested to have an average efficiency of greater than 70% on particles of 3 microns and above. It is not particularly effective at smaller sized particles and there are no claims made that it is. For example, in recent tests performed by LMS Technologies a MERV 8 filter had an efficiency of 5.5% on 0.4 micron sized particles and an efficiency of 59.9% on 2 micron sized particles. This study found that the RCI device was twice as effective at removing 0.4 micron sized particles as a MERV 8 filter. One would assume that this would give an efficiency for the RCI device on 0.4 micron sized particles of less than 15%. In the case of 2 micron sized particles the MERV 8 filter (with 2.5 ACH) was more efficient than the RCI device. So, in other words, the MERV 8 filter running at a moderate level of usage would do a better job at removing particles of 2 microns and above in a whole house than the RCI device could do while running continuously in a 110 square foot room.
This conclusion was supported by the fact that the researchers tested the particle removal efficiency of the HEPA (High Efficiency Particulate Arresting) filter attached to the test chamber. They found that while running the system at a rate that would provide 2.5 air changes per hour (this works out to be just 37.4 cfm) the HEPA filter was 3 times more effective at removing particles than the RCI device. Most stand alone HEPA air purifiers designed for one room use will provide approximately 100 cfm on medium. This would mean that a stand alone HEPA in this same chamber would be 8 times more effective at removing particles than the RCI device. Further comparison testing is required to confirm this conclusion.
The researchers also tested the photocatalytic oxidation process of the RCI device on cell structures. In the smaller 3'X4'X8' chamber they concluded that the high concentrations of hydroxyl radicals and other Reactive Oxygen Species (ROS) had detrimental effects on cell structures. These effects included the destruction of the outer membrane of cells, the alteration of the cell DNA and RNA, and the oxidation of enzymes causing inhibition of cell respiration and cell death. These tests were conducted on virus and bacteria samples that have relatively thin cell walls. However, Hydroxyl Radicals and other ROS's are classified as "free radicals" and have been known to have a link in humans for diseases ranging from alzheimers to heart attacks. The effects of large concentrations of airborn free radicals was not included in this research. Further testing would certainly be warranted.
Also see http://allergyclean.com/news/4.htm
I believe more testing in actual residential conditions is needed before so
many speculative claims about this technology, that will cure all that is wrong
with your indoor air, are made.
Hey Braetheasy, MBarson posted your writeup...good job! Too bad you left out a couple things...but don't worry I will point them out as to what is inaccurate with this article...
Well, us real professional HVAC people have always known that room air cleaners are useless & a scam (can anyone say "Ionic Breeze"?), & this report just confirms that fact.
MBarson, Thank you for showing that you too haven't compared what the BS you posted to the actual report from U of C. If you had you would have realized that the person added words when quoting the document and is nothing more than a competitor/ lying POS who fabricated the truth to discredit the technology. Where you say? Don't worry, I promise I won't forget to point it out. I have the U of C report right in front of me.
The main focus was to determine whether or not the Fresh Air which consists of a 6in RCI cell, a DC ionizer, an RF ionizer, and an ozone generator are effective in killing viruses, bacteria and mold. Reduction of bioaerosols in indoor air.
Outdoor ion levels are usually at typical levels of 3000 positive and 4000 negative per cubic cm. Indoor air however contains mostly positive ions. When negative ions are added the airborn particulate will be attracted to oppositely charged particles causing them to clump together until they are large enough for gravity to pull them out of the air. RF ionization is a slow process. DC ionization is much faster, but only works in the room it is in.
As I said in the other thread, as proven (Verezar et al, 1967) that condensation nuclei as small as 1/1millionth of a micron can accept a charge which means ultimately clumping and removal from the airspace. Proven effective by Boguslaw Maczynski at Balneoclimatological institute at POzan, Poland in 1973.
So it only stands to reason that if it is proven at high altitudes that the air is almost completely particle free due to solar ionization that the same will hold true in the long term. However in pointing out the particle count after an hour or so, one must realize that the ionization will create larger particles out of the smaller ones. So that isn't what ionization is capable of, just what it does in the beginning.
Also the particles used in the first portion of the testing ranged from .02m-2.0 Pretty hard to drop anything smaller when there was nothing smaller to drop.
"Our preliminary tests showed that the air purifyers opperation considerably reduces the bioaerosol concentration in the chamber due to ion emission."
-They then disabled the transmitter to see if RCI by itself drops particles and it doesn't but we never claimed it did.
"As seen from this example (fig 2) the aerosol contamination of .1m particles decreased by a factor of 28 in 1hr and 250 in 2 hrs; the corresponding decreases for .1m particles were 10- and 50- fold. When testing with smoke particles, the aerosol concentration decreased more rapidly."
They also go on to say that the results agree with previously published data on " the effect of unipolar air ionization on airborn concentration."
So the clown that wrote that bogus write up said "the ozone level went from 6ppb to OVER 50ppb in 35min."
That is an outright lie and is not found in the report anywhere! What it does say is that it went from "..006 to .05 ppm in about 35 minutes."
Nice use of the word "over" lets just stick to what the report really says, but that is what I would expect from an "honest" filter guy.
It also says in a "non-ventilated room of ~100m3 (not presented here) suggest that the ozone level can be kept below .05ppm while the unit continuously opperates for many hours."
Wow, that isn't at all what the author of your bogus internet fact was saying!
But your clown said it was over safe levels...too bad that wasn't in the lab report.
"Ozone produced by the RCI cell is not believed to cause significant microbial inactivation because its level was not sufficient."
So the ozone isn't killing the stuff but the RCI is...hmmm, don't worry, I wont forget the hydroxl radical argument either...
But these clowns often cry about it being harmful due to ozone?
So the report found that with RCI
"80% removal of airborn pathogens in 30 minutes"
-Isn't that what you want? Dead germs?
So, it kills stuff and doesn't exceed the ozone standards of the EPA, wow, what a horrible product.
Now on to hydroxl radicals. There is no way whatso ever a hydroxl radical of this kind can make its way into the body. If you knew anything about them you would know that they attatch to stuff so quickly they would have oxidised something far before ever making their way into the body. The main byproduct is hydrogen peroxide, which accoring to the clinical guide to pharmacology in 1984 cannot make it's way into the body because it too would try to oxidise things and you would be left with only water.
I look forward to doing this again...it was a nice attempt but remember not everything online is true...haha I love it! Keep looking, I am awaiting your next attempt to discredit our equipment...you and BE should work together...then you can proofread the nonsence so you can save yourself from the public embarassment!
It's been fun girls but I gotta go!
More research on hydroxl radicals in air? haha ya right they are gone the second they exit the machine and there are so few to begin with...nice try filter guy! I always wanted to collect germs in a filter so i could have the person changing it exposed to hazardous levels and recontaminate my house when changing the filters.
Also the Fresh Air is mainly sold to people who don't have HVAC units in their homes. some do use a Ductworx with a filter system and judging by your argument a filter system and a Fresh Air and a Ductworx would be ideal. The ionization would clump the smaller particles so the filter can catch them and you get the bioaerosol protection from the RCI, so the three together would make a very clean living space. As far as HEPA stand alone units none of you seriously believe they work I hope....I can see in an HVAC system they have their applications but there isn't enough force to draw the air through a lil box and filter it effectively.
Last edited by NHMoldInspector; 02-21-2007 at 07:45 PM.
Wow the irony that it was found on a company site for filter salesmen...some people....just give all filters a bad name ..lol
The title should be, "Beware of lying filter pushers, they will do anything to discredit any device far superior than a filter!"
Hey special ed, the reason most home cleaners like the ionic breeze are scams is because they rely on getting all the air through a box...which is my argument on filters since that is impossible...The difference with us is the purifying plasma and ionizers make their way through the entire airspace and diont rely on all the air coming through the box.
Chaos theory makes it work!
Sorry I did not respond to this thread earlier. I have been helping my parents make the decisions and physical move into a retirement home.
I have been researching and writing these articles for 10 years. During that time I have read many hundreds of research studies and have personally tested over 200 products. At first the testing was only for my own companies. Recently I have also tested some other products (see the Trane CleanEffects thread) at the request of some of my HVAC contractor customers.
I did not post the above article. But anyone could have found it on the www.texairfilters.com site that is listed in my contact information for this forum. You will also find other articles on ozone generators, the Ionic Breeze, RGF, etc.. The article was not written to criticize Ecoquest per se. It just so happens they produce and sell this Fresh Air RCI product. I have my issues with Ecoquest as a company and their marketing methods, but that has nothing to do with the contents of the article. In fact, I have reviewed the contents of the article and do not see where it needs to be changed based on the criticisms above. The bottom line is it does not appear to be a very efficient air cleaner and it is potentially dangerous to those with respiratory diseases. It produces an unacceptable level of ozone. It has a very low Clean Air Delivery Rate. It produces "free radicals" that the authors of the study claim destroys cells.
So, I have no plans on changing the article. However, here is what I will do. I would be happy to test the Fresh Air RCI product. A quick check on e-Bay shows 52 vendors selling the Ecoquest Fresh Air RCI product. It shows a reference retail of $795 but the winning bids seem to be about $150 to $250. These products claim to be "new in the original box." Maybe some of our Ecoquest friends could tell us whether this is the right product or not.
I just got done reading this thread which included the article from Breathe easy, rebuttal form NHMoldInspector and yes the full article form University of Cincinnati, it's late, I'm tired but couldn't resist to add my 2 cents.
I wish the article by Jim would have been more exact about the ozone levels when referencing the U of C article. It's not "over" in 35 min or 5 min.
In both test chambers (non-ventilated), the ozone
concentration gradually increased as the purifier was continuously
operating. In the 24.3-m3 chamber, it increased
from 0.006 to 0.05 ppm in about 35 min, while in a smaller
(2.75-m3) chamber the same increase occurred in approximately
If the article had ozone readings after 35 min or 5 min it would have gone over 50 ppb. He should have pointed out that fact.
I hope we can agree that after 35 min the ozone was over 50 ppb.
This unit does seem to be a poor choice to remove particles. I would take a small portable HEPA any day over this unit.
I will give you the full title of the U of C article and you can make your own decision about what the "main focus" is Control of Aerosol Contaminants in
Indoor Air: Combining the Particle
Concentration Reduction with
Read the full article yourself.
Reading the study again brought out two other interesting points.
The humidity level in the test chamber was between 22 to 28 %, much lower than the average home that can be between 30 and 60 % RH. I Believe Moldi somewhere stated that these units are more effective in higher humidity levels.
If that is true would it not be reasonable that believe that ozone production would also increase in a higher RH environment.
A quote from the Ozone section of this report:
"Some air purifiers utilizing ion emission and, to a greater extent, the photocatalytic oxidation may cause greater increase of indoor ozone concentration than the tested one. The use of such devices in confined occupied air spaces may eventually lead to excessive ozone levels and, in the presence of certain chemical compounds produce nano particles."
Like I have stated before, I don't see any benefit to using these devices. They do produce ozone, they are expensive and I don't see enough real world information backing up thier claims to thier effectiveness. Along with other reports of issues with these types of devices I still stand by my original warning of buyer beware.
That quote you used from the report just states that many of the other devices similar create too much ozone, notice the context is other than the one tested...implying some can be dangerous but not this one.
I would say that the major benefit is killing bacteria viruses and mold and the fact that the ionization will clump particles small enough that dont even move with air so a filter wouldn't work well for that, so the 2 together would probably be a great fit, the smaller partlcles clump and then get caught or dropped.
So the benefits are no odors in your house, no germs, no mycotoxins and reduced everything from all the chemicals off gassed in your house already. I would say that has no place in everyday life either (sarchastic)
Course you could always fog the house with bleach daily but that would really help the air quality as everyone in the house gets poisoned...or braindamage from lysol.
I realize you want to see more testing but to say there is no benefit if it does do what we say it does....are you serious? It stops mold from growing in surfaces, that in itself is worth the money...then kills bacteria and viruses too...and destroys odors from mold or your stinky boots after a hard days work...
....Just the fact that it deactivates spores is worth the money. Some dumbass on extreme makeover home edition thought mold was harmless and tried to clean his mold himself , inhaled spores and died from the infection...so sometime a few spores can hurt you....
Plus as I said before it is for no area less than 250sq ft so that small room was less than that so that would be going against manufacturer specifications. As I stated before it said in a area 100m3 it can be run consistently without exceeding 50 ppb
Last edited by NHMoldInspector; 03-17-2007 at 10:08 AM.
What about the humidity level. Any comment on that. Didn't you state that the unit is more effective the higher the RH. Wouldn't ozone production go up also?
The Fresh Air unit does produce ozone: it states so in the owner's manual. We all can agree ozone is not good for humans even though it can kill bacteria and sterilize the air. The hazard seems greater than the benefit when you consider that the air does not need to be sterile for people to be healthy.
The point about the spores killing someone is extreme in itself. The spores one would find in a home naturally are not a problem. If someone was doing remediation without the proper PPE then I really can't say too much about that and I doubt that if he had a Fresh Air unit he would have been OK. If there is a mold problem then fix the mold problem by getting rid of the moisture problem. Moisture is what needs to be controlled.
Source control, ventilation and filtration will always work and until anyone can prove me wrong that is the basis for my position.
I can't say to much more.
The higher humidity wouldn't create more ozone, the main use of the ozone in the UoC report was generated by the ozone generator. 80% of the ozone created from the light is used in the production of hydroxls and hydrogen peroxide (H2O2) so it is adding those extra oxygen molecules to the H2O already in the air. The Uof C report also said that the ammount of ozone coming from the RCI was so little that it couldn't even inactivate stuff, so the inactivation was noted as from the RCI plasma itself.
At one section they were useing the ozone generator itself...they broke it down to see what does what. That was where the level reading come from.
If you run it on normal and put a meter in front of it you wont pick up anything. in a tube it maintains .01-.02ppb, which is why EQ has a dual RCI based machine without the ozone generator for Canada...since ozone generators are illegal there.
So if ozone is such an issue toyou trial an RCI cell (not a unit- no ozone generator) and throw it in your system for a week and see if you like it...you will smell a difference within hours.
Last edited by NHMoldInspector; 03-17-2007 at 11:20 AM.