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 Mobile ViewENVIRONMENTAL HAZARDS - INSPECT, TEST, REMEDY ASBESTOS IDENTIFICATION IN BUILDINGS ATTIC MOLD BASEMENT MOLD BASEMENT MOLD WATER IMPACT BATHROOM MOLD BIBLIOGAPHY for ENVIRONMENTAL HEALTH, MOLD, IAQ BIOGAS PRODUCTION & USE BIOLOGICAL POLLUTANTS BLACK MOLD, HARMLESS COSMETIC BLACK MOLD, TOXIC & ALLERGENIC BLEACHING MOLD, Advice about BOOK MOLD, Moldy Book Cleaning BOOKSTORE - ENVIRONMENTAL BROWN HAIRY BATHROOM MOLD CACTUS FUNGI / MOLD CAR MOLD CONTAMINATION CARPET DUST IDENTIFICATION CARPET MOLD CONTAMINATION CARPET STAIN DIAGNOSIS CARPET & other STAIN TESTS CARPET TEST PROCEDURE CARPETING & INDOOR AIR QUALITY CAT DANDER CRAWLSPACE MOLD DIRECTORY of MOLD / ENVIRONMENTAL EXPERTS DIRT FLOOR MOLD CONTAMINATION Disinfectants Disinfecting Buildings with Bleach DO-IT-YOURSELF MOLD CLEANUP WARNINGS DRYWALL MOLD DUCT SYSTEM & DUCT DEFECTS DUST ANALYSIS for FIBERGLASS DUST CONTAMINATION FROM HVAC? DUST SAMPLING PROCEDURE EFFLORESCENCE, Salts & White / Brown Deposits EMERGENCY RESPONSE, IAQ, GAS, MOLD FEAR of MOLD - MYCOPHOBIA Fiberboard Insulation Sheathing Mold FIBERGLASS INSULATION MOLD FLOODS & MOLD CLEAN/PREVENT FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP GAS DETECTION & MEASUREMENT GAS EXPOSURE LIMITS & STANDARDS GAS EXPOSURE EFFECTS GAS TEST PROCEDURES HEATING OIL EXPOSURE HAZARDS, LIMITS HEATING OIL PIPING TROUBLES HEATING OIL SLUDGE HEATING OIL TANKS HOUSE DUST ANALYSIS HOUSEWRAP AIR & VAPOR BARRIERS HIDDEN MOLD, HOW TO FIND HOME HEATING SAFETY HUMIDITY CONTROL & TARGETS INDOORS HVAC Systems INDOOR AIR HAZARDS TABLE INDOOR AIR QUALITY & HOUSE TIGHTNESS INDOOR AIR QUALITY IMPROVEMENT GUIDE VENTILATION, WHOLE HOUSE STRATEGIES Air Filtering Strategies Particles in Indoor Air - Chart AIR CLEANER PURIFIER TYPES Air Filter Effectiveness Air Pollutants, Finding & Reducing RADON HAZARD TESTS & MITIGATION Formaldehyde Hazards BIOLOGICAL POLLUTANTS BUY PRODUCTS for MOLD & ALLERGY CONTROL Volatile Organic Compounds VOCs Pesticide Exposure Hazards Lead Exposure Hazards Asbestos Hazards CARPETING & INDOOR AIR QUALITY Combustion Appliance Contaminants BACKDRAFTING HEATING EQUIPMENT Fireplace & Woodstove Contaminants INDOOR AIR HAZARDS TABLE INDOOR COMBUSTION PRODUCTS & IAQ MOLD INFORMATION CENTER ACTION GUIDE - WHAT TO DO ABOUT INDOOR MOLD ODORS GASES SMELLS, DIAGNOSIS & CURE OXYGEN - O2 OZONE as a "CURE" for TOXIC INDOOR MOLD or ODORS OZONE AIR PURIFIER WARNINGS Ozone Air Cleaners Not recommended Indoor Ozone Gas Harmful Ozone Air Cleaners & Chemical Reactions Ozone-Generators & Indoor Air Chemistry Ozone Generators for Indoor Air Pollution? Ozone Air Purifiers for Odors? Ozone to Prevent Mold Growth? OZONE HAZARDS Hazards of Indoor Ozone Gas Ozone to Kill Toxic Mold Ozone Air Purifiers Ozone Indoors - More Odor Problem Ozone to Get Rid of Odors in a Car OZONE EXPOSURE STANDARDS OZONE TESTS OZONE MSDS OZONE TOXICITY OZONE ODORS, MOLD, REFS SMELL PATCH TEST to Track Down Odors" More Information |
Ozone air treatment warnings: this article provides government and other authoritative warnings about using ozone generators and ozone air purifiers in buildings to "purify" indoor air or to "kill mold" in buildings. This article explains the effects of and warnings about using ozone in buildings for these purposes and warns consumers about misapplication of and health risks from ozone in buildings. Because at least some of these claims are based on marketing desire, not good science, and because ozone exposure can be both dangerous and ineffective indoors, we report here with information and references on this topic. InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers nor with topics or services discussed at this website.© Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website. WHAT IS OZONE: Ozone - O3While there are many sound and important uses of ozone (such as for medical disinfection under controlled conditions), in general this is an idea which ranges from bad to dangerous in the home. Ozone is widely promoted by ozone generating equipment companies and cleaning services for use in indoor building environments to deodorize, disinfect, "kill" mold, and for "general health". Ozone generators are also promoted for use to reduce the level of airborne particles, pollen, animal dander, and allergens, ostensibly to improve indoor air quality for asthmatics and people with allergies.Ozone or O3, or "trioxygen" is a molecule made of three oxygen atoms. In this form, and referred to as an "allotrope" of oxygen, ozone is an unstable gas - that means it breaks down into oxygen molecules. Problems Encountered Using Ozone to Get Rid of Skunk, Indoor Odors, or Mold Smells?But neverhteless, ozone is a highly toxic gas. Now even highly toxic substances can be encountered safely. The main concern with ozone exposure is that the ozone concentrations to which people are exposed
A second class of problems when ozone is misapplied indoors is the creation of lingering odors due to the oxidation effects of the highly reactive ozone gas while it was present. In our OPINION, following ozone use as a "deodorant" if there is no lingering odor from oxidized materials in the enclosed space (a building, car, boat, RV, etc), and considering that ozone itself is so volatile that it does not hang around in the building, then its application probably did not create a problem for the building. Ozone is never recommended as a "mold killer" since that strategy is fundamentally flawed in the first place. Details are at MOLD KILLING GUIDE. A separate question remains, in some cases, of whether or not building occupants have been exposed or are being exposed to harmful ozone levels. See OZONE AIR PURIFIER WARNINGS and see OZONE MSDS and OZONE TOXICITY. Using Ozone Left a Smell in our Home - How do I Get Rid of It? - Using Ozone Indoors to Cure Skunk Smells, Mold Odors, and other StinksThis quote from a reader's email pretty well sums up what happens if you overdo it when using an ozone generator indoors to try to "kill off" odors:
We have investigated a number of cases of misapplication of ozone generating machines both to "kill mold" (no good, you're leaving toxic or allergenic particles, and you haven't corrected the reason for mold growth in the first place). We have also investigated several cases of excessive ozone-use to try to remove odors from buildings, including fire or fireplace smells, mold smells, pet or animal smells, skunk odors, smoking odors, etc. Here is another similar case:
Use the Smell Patch Test & Look First at These Prime SuspectsIf you have aired out the building and days or more have passed and you still smell a "new" chemical or plastic or other odor that was not there before you tried using your ozone generator, you'll need to determine just what materials were oxidized by the high levels of ozone in the building. It's been our experience that once you identify and dispose of the new-smelly material you'll probably be fine. However, by nose alone, it is very difficult to track down a specific indoor material to the odor source in this case. Jeff May suggested[1b], and I've more extenisvely explained and documented an inexpensive means to track down odor sources to indoor materials or furnishings: see SMELL PATCH TEST to Track Down Odors for details. The procedure works best if you have as the "smeller" a person with a good sensitive ability to discriminate among odors. The smeller can briefly go indoors to become familiar with the odor whose source you are seeking. But they then have to stay outdoors breathing clear air long enough to regain their original smell sensitivity. (When we are exposed to an odor for some time, our brain starts to tune it out.) So typically you bring in the smeller, let her sniff and agree that she will recall the objectionable odor, then give her a few days off while you prepare the test we describe above. You use the foil, tape, and paper towel procedure I describe at the link above. Here are some examples of material we've found giving off horrible smells after misuse of an ozone generator. (Misuse means using the ozone generator to try to kill mold, or running an ozone generator too long at too high a setting in too small a space - overdoing it).
General Use of Ozone Generators nor Ozone Shock Treatments as a "Cure" for Building Mold or Odors is Not RecommendedWatch out: Ozone is a highly toxic, oxidizing gas. It can be absorbed into the body via inhalation, skin or the eyes. It can also oxidize building materials. See the Ozone hazard and use warning articles listed at the end of this article. Watch out: In-Home or "portable" ozone generators and industrial or "shock treatment" ozone generators not only fail to find and remove the source of mold or building odors, in addition ozone concentrations generated by ionic air purifiers can exceed (industrial) levels permitted by U.S. Environmental Protection Agency. This problem is more severe when
In addition, a ban of in-home ozone producing air purifiers was announced by the California Air Resources Board in September 2007. This law requires testing and certification of all types of air purifiers to verify that they do not generate excessive ozone. See "Health Hazards of Ozone-generating Air Cleaning Devices", State of California-Health and Welfare Agency, Department of Health Services, Indoor Air Quality Section Before Using Ozone or Gutting a Building to Get Rid of Odors, Try the Smell Capture Patch Test to Pin Down a Specific Indoor Odor SourceOur friend Jeff May suggested this procedure for pinning down a specific odor test in buildings - it has worked remarkably well for us where ozone had caused an indoor smell that could not be tracked down. Details of this procedure to track down the source of indoor odors is especially useful after an ozone treatment problem that has left odors or other indoor air quality complaints in the building. Details of the smell source identification method are at SMELL PATCH TEST to Track Down Odors. We have had very good results with this procedure when used to narrow down odor sources in an ozone-treated building, and we had up to 95% repeatability when we used additional smell test patches. Second-Cause Odors in Buildings Following use of an Ozone generatorAt OZONE AIR PURIFIER WARNINGS we include an example report of horrible building odors that were caused by attempts to get rid of an indoor odor using an ozone generator. when high levels of ozone have been produced in an enclosed space, we find that other materials in the space become partly oxidized, subsequently giving off horrible, often chemical-like odors. We have traced odors to painted surfaces, furniture, upholstery, curtains, carpeting, carpet padding, and other materials. To track down the source of post-ozone-treatment smells, try making a smell-patch test - see SMELL PATCH TEST to Track Down Odors to determine just which building component has been oxidized. Following this procedure we can often narrow down the source of post-ozone-treatment smells to a single material that can then be removed or remedied, such as carpet padding or a specific piece of furniture. More about tracking down odors in buildings is at ODORS, Smells, Gases in Buildings-Diagnosis & Cure. Frequently Asked Questions about Ozone Use Indoors as an Odor Killer or Mold KillerQuestion: how do I get rid of high ozone concentrations produced by a spark generatorHow do you rid a room of highly concentrated ozone produced by a spark generator?? 400sq ft, various items of wood furniture, paneling, bed with foam matress, etc?? - Charles 12/2/11 Reply: if you smell ozone it's probably unsafe; if you smell something else later it may be due to an ozone treatment "overdose"Charles, in the article above we make suggestions for getting rid of ozone smells indoors. If you are inside of an enclosed space while ozone is being generated at levels that you can smell, it is unsafe. And ozone is ozone. It doesn't matter how it's produced: by spark generator or any other means, the molecules are the same. What does vary among ozone treatments and the people who use them, are
Actually unless you are smelling ozine while you are in an enclosed space while ozone is being generated (something that is most likley unsafe), you are not smelling ozone - it's very volatile and doesn't hang around. So the ozone itself, and its characteristic odor, will dissipate rapidly, minutes to hours, of fresh air ventilating of the space where ozone was produced. Most complaints we receive are from lingering odors after an ozone overdose of an indoor area in an attempt to remove smells. An "ozone treatment overdose" is my general term for applying ozone at levels or at a duration long enough to cause chemical changes, probably oxidation, of other indoor materials (carpets, curtains, foam cushions, plastics) that in turn leaves a lingering, obnoxious odor that just doesn't go away satisfactorily. Please review the article above and you'll see an outine of how we suggest you proceed. Question: I have asthma and was exposed to ozone in an enclosed space for a few minutes.Will that cause health problems?I have asthma and was in a closed room with the ozone machine working for a few minutes, would that cause me health problems in the future? - Sandy 10/26/11 Reply: a brief exposure to low levels of ozone should not cause lasting health problems for most people, but some are at extra riskSandy, I can't give a "for sure answer" to your question about ozone exposure, your doctor would have to do that. At OZONE TOXICITY we report that
As with any potentially harmful or irritating substance exposure, the risk is a function of several variables including This means that even a brief exposure to very high levels of ozone could injure someone. See Ozone Gas Exposure Hazards for quantitative levels and permissible exposure limits (PELS) for ozone. Of course now, after the fact, you will most likley have no idea of what the actual level of your ozone exposure was. But in general, a brief exposure to a closed room "for a few minutes" is very very unlikely to produce a measureable future health problem provided Ultimately this is a question you need to discuss with your doctor or with a pulmonologist who knows your medical history.
Questions & Answers regarding this articleQuestions & answers about government & other expert warnings concerning the use of ozone generators indoors as air purifiers or for mold remediation. Ask a Question or Search InspectAPediaHTML Comment Box is loading comments...
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Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website. ODORS GASES SMELLS, DIAGNOSIS & CURE Ozone Gas Exposure Hazards OZONE ODORS, MOLD, REFS: References on Ozone, Odors, and Mold
Ozone Hazards OverviewExposure to a level you can smell or exposure to ozone over long periods at levels greater than 0.05 ppm for 24 hours at a time is likely to be dangerous: [2], [3] Health hazards to humans and animals occur and can be severe at ozone levels used for indoor cleaning purposes. At least some people can smell levels of ozone down to 0.05 ppm. This odor-detection level is already half-way to the recommended limit. If you are generating ozone indoors, even at "low" levels a problem may be present. People become desensitized to odors in a short time, perhaps 20 minutes. So if you do not smell it, the ozone level could still be hazardous. Problems include:[4]
Use of ozone to "remove" or "kill" mold is ineffective, not recommended, and may be dangerous. Even if ozone were applied at a concentration and for a duration sufficient to "kill" every mold spore in a building (which is a very dubious claim), depending on the mold genera/species present there is a good chance that the process leaves toxic and allergenic particles in the building. OZONE TOXICITY: - How toxic is ozone, general background, levels of ozone gas toxicity, ozone gas applicationsThe following information about Ozone is quoted from "Health Hazards of Some Gases" [8] "Ozone is a kind (called an "allotrope") of oxygen . It is formed in the ionosphere by the action of ultraviolet radiation from sunlight on oxygen. Lightning strokes are another natural source of ozone and the characteristic odor of that material can often be noted during and after a thunderstorm. When pollutants are emitted into the air either by man or nature, almost all are eventually removed by one or more of several processes including reaction under the influence of ultraviolet radiation. One series of such reactions results in the formation of ozone as a "secondary" (formed by reaction in the air) air pollutant, often in rather high concentrations (several tenths of a part per million). "As ozone can be formed by nature's sparks (lightning), it can also be formed by man's. Whenever an electrical spark or corona occurs in air, some ozone is formed. This accounts for the characteristic odor noted near an operating electric motor such as an electric shaver. "Because ozone is found in so many places, its toxicity (ability to injure a living organism by other than mechanical means) has been investigated extensively since the early 1900s. Experimentation has shown that the odor of ozone can be detected and identified by most people at a concentration of from 0.02 to 0.05 ppm (parts ozone per million parts air + ozone). As the concentration increases to a few tenths of a part per million, the first effect noted is likely to be a feeling of dryness in the back of the throat. If a concentration on the order of 0.2 or 0.3 ppm is inhaled more or less continuously for several hours to a few days some lung irritation may result. "Higher concentrations can produce several kinds of toxic effects if exposures are sufficiently prolonged. Eye irritation (despite newspaper and TV accounts seemingly indicating otherwise) occurs only at concentrations high enough to result in other, more severe, toxic effects. "Ozone is a very reactive substance. It will readily react with just about any material capable of being oxidized, and with many that are not. The material with which it reacts may be a gas or vapor, a particle floating in the air (a mold spore, for example), or a solid (or liquid) surface. For this reason, when ozone is present in most enclosed spaces its concentration declines quite rapidly with time. Of course, if ozone is being generated more rapidly than it is destroyed by reaction, its concentration can build up. This is the main reason why devices that produce relatively large amounts of ozone are safe only in relatively large enclosures and why the ozone generation rate should be reduced in small enclosures. "Ozone is well known for its ability to eliminate certain odors. How this is accomplished is controversial. At concentrations just above the odor threshold, some odors do seem to vanish. The main reason for this may be ozone's ability to desensitize the olfactory apparatus so that the odors can no longer be perceived. Some evidence indicates that this may be the case at least occasionally. Other evidence indicates that ozone may react with the odor-causing substances, eliminating them from the air (this is probably the only mechanism that operates when concentrations are below the odor threshold). "Finally, some people have insisted that even if ozone does not paralyze the olfactory sense, its odor is such that it "masks" other odors. Perhaps all three mechanisms operate, each in its own area of effectiveness. "As with all other materials, ozone has a dose-effect relationship with a threshold. That is, once the threshold dose has been exceeded, toxic effects are proportional to dose. For inhaled gases, dose is proportional to both time and concentration. If the duration of exposures cannot be controlled (as is usually the case), then the concentration must be kept low enough so that no injury will occur even from prolonged and repeated exposures. For ozone, that "threshold" concentration is 0.1 ppm. So long as concentrations are kept at or below that level, injury is not expected even in the most sensitive workers so long as their exposure durations coincide reasonably well with or are less than the 8 hr/day, 40 hr/wk regimen. This "threshold" level is accepted by the American Conference of Governmental Industrial Hygienists (and is called the Threshold Limit Value by that organization) and by the Occupational Safety and Health Administration, OSHA. The TLV or OSHA's Permissible Exposure Level (PEL) is not a fine line between safe and non-safe. Instead, it represents the best judgment of a group of experts of the highest concentration that can be inhaled repeatedly by a population of workers with no resulting injury. Higher concentrations may or may not have any particular effect on a specific individual. "Ozone is a highly toxic gas but even highly toxic substances can be encountered safely. The main concern with this material is that concentrations to which people are exposed do not average more than 0.1 ppm over an 8-hr day, and do not exceed that value by more than a factor of 2 or 3 during the exposure." Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Allergies, Allergens, Allergy Testing in Buildings - References & Products
Mold Contamination Testing, Cleanup, Prevention: references & products
OTHER IAQ ISSUES: How To Find and Address Other Indoor Air or Indoor Environment Contaminants Besides MoldMold or allergens may not be the only or even the main indoor environmental contaminant. Don't let media attention to mold cause so much enviro-scare fear that other, possibly more urgent hazards go un-addressed.
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