I’m testing an electronic air-purification system made by a company called Living Air. I’m told it uses ozone and generates negative and positive ions in the air which causes sawdust and other airborn matter to fall to the floor. The unit is about $700.00 and before making such a sizeable investment I would appreciate hearing for others who may be familiar with this or like products. E-mail [email protected]
thanks much, Ken
Replies
Ken, if you're buying something for your shop, I'm not sure why you'd want the dust to "fall to the floor."
You could take the same $700 and put it into both a dust collector and an air filtration unit (hangs on the ceiling), and get rid of the dust!
IMHO, you're being sold a bill of goods, though I must admit, I've never had experience with one of these machines.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Edited 9/15/2002 12:18:50 AM ET by forest_girl
Stratospheric Ozone is the lovely stuff that block UV penetration to the Earth.
Tropospheric Ozone is air pollution .It is the major non- particulate component of smog. It is a reactive free radical that causes airway inflamation, worsening of asthma, emphysema and COPD. It wil cause pleuritic chest pain and cough depending on the concentration. 0.4ppm is like a bad day in Los Angeles. 4 ppm (If I recall) kills mice.It will degrade anything made of rubber. I don't know what it will do to wood.
I was recently in Lowes and saw the air cleaner isle. Several made Ozone. What are these manafactures thinking?
Put the $700 toward improving shop ventilation and dust collection in other ways.
Frank
PS I did 2 years of research on Ozone Dosimetry for the US EPA in the early 90s.
Your message should be addressed to dovetail, not to me. forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Frank -
Now that we've been having this lengthy discussion about electrostatic air cleaners, my curiosity has been aroused. Perhaps it's the power of suggestion but the past coupla nights working late in my home office I seem to notice my eyes feel drier than normal - they're usually pretty dry anyway from staring at a computer screen all day (and most of the nights). But thanks to all this talk about ozone .... (grin)
The question -
Do you know of any kind of instrument for measuring ozone emmisions from one of these beasts? Anythying that would be remotely affordable by an interested and/or concerned home owner? Do HVAC people have such an instrument? Would a canary in a cage sitting in front of the air flow provide an adequate early warning system? (grin)
Dennis in Bellevue WA
[email protected]
Dennis,
Ozone analyzers are available but probably not commonly so.The one I used used a photovoltaic cell with some sort of hydrocardon (isobutane?) in it. The amount of ozone in the room will be determined by size of the room, ozone production and the # of air exchanges an hour from the room.
Sorry, this is probably not helpful.
Frank
Sorry, this is probably not helpful.
On the contrary - it's more than I new before I asked!
Thanks, Frank. I'll check around.
Dennis in Bellevue WA
[email protected]
Forest Girl: I do use a dust collector and If I'm not mistaken the unit I'm testing is a type of filtration filter. Whether or not it is preferable to the kind you see in all the catalogs that hangs from the ceiling is what I was hoping to learn on this board from someone who has used similar products.
Thanks
> ...I was hoping to learn on this board from someone who has used similar products.
I think what I have in my office, in my home, is similar to what you're describing. Mine's made by Honeywell, cost more like $300 so probably isn't as big, and is suitable for an average sized bedroom for air purification purposes.
OK ... so I'm a pipe smoker and my wife doesn't smoke. The office is the only place I smoke in the house. The filter thing runs constantly in there. You can't smell smoke in any other room of the house either upstairs or downstairs. We have a neighbor who is chemically sensitive. She doesn't smell any traces of pipe smoke in the house when she visits. (Just my old coveralls in the garage/shop -grin-).
When we bought the unit, the sales guy recommended washing the electronic do-hickey once a month in the dishwasher. Judging from the looks of the wash water left in the bottom of the dishwasher, it must be working. There's also another charcoal filter pad on the intake side of the box as well.
While I believe a unit like this works somewhat OK for taking out smaller particulate matter from the air than anything, say less fine or sophisticated than a high end HEPA filter system, I would hardly expect it to do any good in a workshop.
As far as the ozone thing goes, I've had this unit in my office for probably half a dozen years and don't 'smell' any ozone to excess. Ozone is generated, from what I've been told (correct me if I'm wrong, please) only when there's a big discharge across the plates/wires of the unit. This doesn't happen all that frequently with mine, only once in a while. The dust/chemical particles come in past some charging plates that give them a static charge one way or the other which makes them stick to the plates with an opposite charge.Dennis in Bellevue WA
[email protected]
It is thorougly NUTSO to intentionally inhale Ozone. Trust me on this one.
Frank
Bronchoscopic determination of ozone uptake in humans . Gerrity, Timothy R., Frank Biscardi, Arthur Strong, Alan R. Garlington, James S. Brown, Philip A. Bromberg. USEPA Clinical Research Branch, Health Effects Research Laboratory and University of North Carolina Center for Enviromental Medicine and Lung Biology, Chapel Hill, NC, USA.
APStracts 2:0161A, 1995.
Measurements of ozone uptake efficiency in the human respiratory tract provide critical information toward understanding ozone dose-response characteristics. Toward this end we measured ozone uptake efficiency by different regions of the respiratory tract between the mouth and bronchus intermedius . Ten healthy, resting, non-smoking male and female subjects underwent transnasal fiberoptic bronchoscopy while supine inside a controlled exposure chamber containing 0.4 ppm ozone. A bronchoscope was sequentially positioned at the bronchus intermedius (BI), main carina (CAR), upper trachea (UT), and above the vocal cords (LAR). Air samples at each location were drawn into a rapidly responding ozone analyzer through a teflon catheter that was inserted through the channel of the bronchoscope into the center of the airway. During sampling subjects breathed through a mouthpiece connected to a pneumotach at a paced rate of 12 breaths per minute. Each measurement at each anatomic location was bracketed by two measurements of airflow and ozone concentration at the mouth (M). Integration of the product of the flow and ozone concentrations during inspiration and expiration provided the ozone mass passing each anatomic location during each phase of respiration. Since the flow used for computation of mass at BI was the flow at the mouth, the computed mass at BI represents the total ozone mass passing all anatomically comparable locations. On inspiration the uptake efficiency of ozone by structures between the mouth and each location, j, (EM-j) were 0.176+/-0.037 (SE), 0.271+/-0.024, 0.355+/ -0.030, and 0.325+/-0.031 for LAR, UT, CAR, and BI respectively. A significant effect of location on EM-j was found by analysis of variance (p<0.0002). Pair-wise comparisons showed that EM-j increased as the lung penetration increased except between CAR and BI which were not significantly different.
Received 27 June 1994; accepted in final form 7 April 1995. APS Manuscript Number A640-4. Article publication pending Journal of Applied Physiology. ISSN 1080-4757 Copyright 1995 The American Physiological Society. Published in APStracts on 25 April 1995.
Edited 9/17/2002 7:28:04 PM ET by BISCARDI
Edited 9/17/2002 7:33:19 PM ET by BISCARDI
Dennis: Thanks for taking the time to post. I appreciate the imput. The guy who left the unit for me to test also offers a unit for inside the house. It sounds like yours, but more costly. He demonstrated with ammonia on a rag and held the rag in front of the unit. the odor disappeared quickly. He said the unit will eliminate most household odors. The one in the shop is designed more to eliminate dust and particulates in the air. I hope others will join this thread. I hope to learn more.
Ken
> ....The one in the shop is designed more to eliminate dust and particulates in the air.
This is just my personal opinion and intuitive reaction to that claim: dust particles of the size we're talking about in a woodworking shop are large enough to be filtered out with a good quality bag system. Go HEPA if you're paranoid. An electrostatic system will make all the dust settle to the floor can do so only if it adds mass or charge to the particles. I don't see anything within the laws of physics that would permit it to add mass so it must be adding charge. Meaning that the dust particles must,then, be attracted to and stick to surfaces. The floor is most likely not the only surface in your shop. (grin). You're still gonna have cleanup regardless.
Now if the system is designed to trap the dust particles in the same way an ordinary room air filter catches pollen and smoke particles, then I'd suspect it would require frequent, perhaps even daily cleaning and maintenance to maintain effectiveness.
Just my casual, non-intellectual observations.
Dennis in Bellevue WA
[email protected]
Dennis: Your analysis makes sense. Thanks, I think I'll go for the purifier that hangs from the ceiling
ken
> ....I think I'll go for the purifier that hangs from the ceiling
At the risk of stirring up more dust than necessary (pun intended), after all this talk, are you seriously considering an electrostatic air purifier in your woodworking shop? I really think if you want to eliminate as much dust, shavings, sawdust, .... anything not too heavy to be moved by a swift current of air, the best and surest way would be to have a regular dust collection system, installed *outside* the shop, filter bags and all. And not near a window or door that's left open lots in the summer.
But - in the end, it's your shop, of course, and you're at liberty to do as you like. I for one would, however, like to hear some followup once you've had the purifier in use for a few weeks/months.
Dennis in Bellevue WA
[email protected]
Dennis: Thanks to yours and other posts I decided not to use the device. As I live in a community where I can not add anything unsightly to the exterior of my house any ducting will have to reside inside the shop. I use a portable collector on rollers with each of my machines and a Fein vaccuum on the hand-helds. Do you recommend one of the common type air filters that resides on the ceiling? Below is something I pasted from a website comparing air filtration methods. Hope you find it interesting
3. Negative Ions
How Negative Ions WorkNegative ions purify the air by magnetically attracting to pollutants until these newly-formed larger particles become too heavy to remain in the air you breathe. Biozone air cleaners continually produce negative ions and ozone, so even if one of these fallen particles is kicked up into the air, it is quickly removed again. These fallen particles are typically collected by your normal cleaning activities. The most important thing though, is that they are taken out of the air, preventing you from inhaling them into your lungs, which is how they cause problems.
Thanks Ken
Edited 9/19/2002 4:03:46 AM ET by dovetail
Dennis: Your post was terriffic. What does it mean? I read some statistical data but was unable to draw any conclusions. Could you explain in laymans terms please
Thanks Ken
I think you were asking what the abstract means. Ozone is a component of smog. The EPA wants to regulate it because it has well documented adverse health effects. It is a reactive gas, meaning it reacts chemically with the components of airway water. It is a reactive free radical of oxygen. As it goes down the airway some of it dissipates as it reacts with the airway lining.The amount in the alveoli isn't what goes in your nose. EPA wanted to know how much you breath reaches your lung. We measured it directly in a rather slick way. The previous mathematical models were incorrect.
Anyhow, it is a nasty reactive substance.It isn't just a clean smelling substance that cleans the air. If you look in the airways of people who breath it experimentally their airways are red and inflamed. It effects subjects spirometry, response to inhaled allergans, it can cause chest pain and is all around nasty stuff.
Please don't introduce it into your enviroment intentionally.
A very readable EPA review on Ozone generators can be found at
http://www.epa.gov/iaq/pubs/ozonegen.html#table
It describes the effect on odors, particles etc.
Frank
Frank -
With respect to ozone detectors, they seem to run in the hundred(s) of dollar range. One web site listed and illustrated what looked like a hand held device that was priced at ~$650. They did have, however, some patch kits kinda like radiation detection badges. The replacable tape detection part would turn brown at .01ppm ozone. That seems pretty sensitive! These patch kits were like $32 a set. Ten of the replacable tape patches in a kit.
I'm not sure my air purifier/filter generates enough ozone to make something like this worthwhile, though.
Dennis in Bellevue WA
[email protected]
Great reference. Thanks for the link, Frank.
Dennis in Bellevue WA
[email protected]
> .... I think [dovetail was] asking what the abstract means.
Yeah, sorry, Frank, I realized that after I posted and read the rest of the articles.
Dennis in Bellevue WA
[email protected]
> ....I read some statistical data but was unable to draw any conclusions. Could you explain in laymans terms please
Well, I'm really only a layperson myself so I'll explain as best I can how these electrostatic air cleaners work. Anyone with a broader and more thorough understanding will, I hope, fill out and/or correct details.
There are two sets of charged elements that the air is drawn through. These are charged by circuitry within the box. Pretty simple stuff, very high voltage but, to my knowledge, low amperage. This translates, again, to my knowledge, into a rather significant jolt if you make contact with both but not life threatening as compared to high amperage stuff.
On mine, there is a series of fins about 1/16" thick x 1" deep spaced an inch or so apart. Between these plates there are stretched some fine wires, one wire between each pair of fins. A fan in the front pulls the air through these fins. Evidently, in the process, dust, polen or about any other particle down to a certain size is given a charge of electricity. This I can't explain how. There are some things you have to take on blind faith, I guess.
After this assemply of fins and wires, there is another set of thinner fins, spaced about 1" apart. These, I presume, are also charge but with an opposite charge than the first set. The principle being that as the particles pass by the first set of fins and wires and pick up the charge, they're attracted to the other fins on the way out.
Some years ago these kinds of air filtration systems were marketed for home heating systems. They fit in line with the supply ducts in a forced air heating system. One of the major complaints from people I know that had them was persistent dryness and sometimes minor throat irritation. Which is, as has been amply demonstrated by other posters, a direct result of the ozone produced by the high voltage discharge when these things would "zap" larger dust particles or otherwise dissipate built-up static charges.
If you live in an area where you get lots of lightening you've probably experienced the smell of the air after an espeically heavy electrical storm. This is the result of ozone production by the high heat energy of the electrical discharge of lightening.
It has been plainly and I agree, correctly demonstrated and explained that ozone is not a good thing in your home. As far as I know, the kind(s) of units being produced these days for air purification in bedrooms, etc., do not produce ozone at any level that might be considered harmful. At least I hope not since I work all day in my office with one sitting about six feet from my desk.
Where they fall down is they simply drag air in from the back and expel it at the front. There's really no circulation to speak of. I think the best installation would be hung from the ceiling in the middle of the room or better, hung from the ceiling with some sort of duct to draw the air from one side into the unit to be expelled at the other. They seem to work but I'll admit, the jury's still out with respect to the ozone issue.
Dennis in Bellevue WA
[email protected]
Ken,
I don't know abut the specific product your testing, but my wife did some research on various air cleaners I think she told me those charged particles are hard to clean up...makes them stick to things?
For dust control, the other issue is air turns in the room per hour. At $700 this sounds like a big unit, but can you get 10 (a minimun) of air turns per hour?
After looking at the various options, I took some old box fans I have (21" square) made a small frame, put in a rather good furnace filter into the frame (back side of fan), hung from ceiling up side down (to get at switch). If I turn both fans on high it's like that 'no-bugs' commerical....lol
Edited 9/15/2002 7:24:02 AM ET by BG
Thanks. I'll check it out
I've used the Jet AFS1000 air filtration system and also recently purchased a single stage Delta 50-850 DC and equipped it with Oneida filter bags (1 micron). Now I wonder why I waited so long to get a DC. My biggest problem now is cleaning up all the dust from before( shop vac days). Between the AFS and DC, I have very little airborne dust. Collect it at the source. What a difference. Some larger particles still get on the floor, but it's nothing like before. I'd spend the money on a good DC, cyclone if you can afford it, and an air filtration system that will turn the air in your shop.
Thanks Craig. I wonder if your system works on the same principle as the unit I'm testing. Do you know if it affects the negative and positive eons to rid the air of fine dust particles?
Ken
The Jet AFS 1000 that I have has an electrostatic outer filter, so it will have a potential differnce to attract the particles. It does not use ionization, just an outer filter and an inner filter bag.
When my outer filter gets caked, I take it down and tap it out. I have a spare filter so I rinse it out occasionally. I also vacuum the internal filter, not as often.
Between the DC and AFS, it has drastically reduced the amount of dust flying around in my shop. It's not 100% dust free, but I am still working on my dust collection ducting, miter saw hood, and downdraft table.
Edited 9/17/2002 2:41:37 PM ET by craig
We use ozone machines at work. We have to deal with dust from plaster, acrylic resin, wood, plastic, carbon/graphite, fiberglass, steel, titanium, aluminum, and talc. The machine is excellent for knocking the dust down. One minute the air can be cloudy from sweeping(the sweeper is lazy) and in four to five minutes the air is clear again. It does require dusting and sweeping since the dust does fall to the floor and on everthing else. The machines are not dust collectors in themselves.
Dovetail,
Called a doctor friend on this one - he's a professor of medicine at Washington University, St. Louis. He concurs with above posts: ozone is harmful to the respiratory system. He says the business with the ions is a bunch of ... well, let's just say nonsense.
Jeff
Jeff: Imput like yours was exactly what I had hoped for when I posted. This is the best research I could have done. I appreciate your help
Ken
I often (and unfortunately) visit the About.com asthma forum. There have been many inquiries about ozone producing air purifiers and the advice given is to avoid them. Ozone is the major lung irritating constituent of air pollution and is the one most tracked. The EPA recently revised its ozone limits downwards and was challenged in court by Pollution Inc (a tongue in cheek term for the nation's corporate polluters). The EPA won based on the science.
I've got a dust collection system myself. I've just completed a small addition to my shop and the dust collector and air compressor will go out there when I finish the wiring. This way, the small (respirable) dust generated will go into the great outdoors rather than exit the bags back into the shop air.
Dave -
I think Dovetail inadvertently credited some of or perhaps all of what Frank provided to me. For one thing, the abstract didn't have the standard "reply" button at the bottom so perhaps Dovetail mistakenly attributed it to me instead.
In any event, I hope everyone who is interested in this matter took the time to visit and read the page Frank pointed us to. It went further than anything said here to point out the dangers of ozone and the fallacies being perpetuated by these types of devices. I was, however, pleased to learn that electronic particle filters are, to some extent effective and do not fall into the classification of "ozone generators".
I agree, - when someone like Frank offers the obvious expertise on a subject, it deserves recognition.
Thanks again, Frank.
[email protected]
Dave: I may have thanked Frank in an e-mail or possibly have overlooked a response. Many have contributed to the thread and while I'm grateful to all I could have missed a thank you. This does bring up a question, and I hope others will chime in here. I question whether it's fair for readers of these posts to wade through countless thanks yous. Isn't it fair to assume all who share in these boards are appreciative and demonstrate that appreciation by helpiing others as they have been assisted themselves? Just a thought. Please keep this going. I'd really like to know if Dave's admonshment was appropriate and deserved
Thanks to all! Ken
No hard feelings.People are busy and sometimes don't read through all the messages and go to all the links.
Frank
Well, thank you all!
Did anyone read/know anything about any ozone produced by the so called electrostatic air cleaners installed as an upgrade on home furnaces? Do they make it or not? Any ideas on amounts?
> ...Did anyone read/know anything about any ozone produced by the so called electrostatic air cleaners installed as an upgrade on home furnaces?
Just came back from our local Western WA fair where there were several reps from the likes of Trane and so forth. A couple of them had slide-in electrostatic air cleaners on display. I asked them if the mfr's had addressed the problems of the earlier models with respect to ozone production due to the static discharge of electricity. Their eyes kinda glazed over in reaction to three syllable words and didn't really have much an answer. I suspect they should have, by now, since ozone production seems to be on the EPA hot list. Probably the best or only information will be direct from the mfr. would be my guess.Dennis in Bellevue WA
[email protected]
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