POST a QUESTION or COMMENT about sources of authoritative information about proper and improper uses of ozone, ozone generators, & about ozone exposure levels & hazards
Ozone exposure & hazard references: This article provides technical sources & references regarding the effects of using ozone in buildings for these purposes and warns consumers about misapplication of and health risks from ozone in buildings.
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.
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
- Daniel Friedman, Publisher/Editor/Author - See WHO ARE WE?
Ozone & Ozone Treatments for Odors or Mold Contamination: References & Technical Documentation, PELS, MSDS
While there are some 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.
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 have
collected some information and references on this topic.Editor's note:
Sampling for gases in air such as VOC's, MVOC's, toxic chemicals, and combustion products.
Unfortunately no single test or tool can detect all possible building contaminants. We use methods and equipment which can test for common
contaminants. If the identity of a specific contaminant is known in advance we can also test for a very large number of specific contaminant
gases in buildings.
We use gas sampling equipment provided by the two most reliable companies
in the world,
Draeger-Safety's [website http://www.draeger-safety.com/ST/internet/US/en/Products/Detection/Drager-Tubes/Pumps/accuro/pd_accuro.jsp ] detector-tubes and Drager accuro bellows pump,
the Gastec cylinder pump
and detector-tube system produced by Gastec or Sensidyne, [ http://www.sensidyne.com/Tube/TubesProduct.htm ] and
we also use Sensidyne's Gilian air pump [http://www.sensidyne.com/GIL/gilMain.htm]
For broad screening for combustibles and a number of other
toxic gases and for leak tracing we also use Amprobe's Tif8850. All of these instruments, their applications, and sensitivities (minimum detectable limits) for specific
gases are described in o
[1] Ozone exposure limits: NIOSH REL: C 0.1 ppm (0.2 mg/m3);
OSHA PEL: TWA 0.1 ppm (0.2 mg/m3)
[2] Ozone and other contaminants discussed, New York State Department of
Environmental Conservation, http://www.dec.state.ny.us/website/dardata/airmon/parametertextpage1.htm
[3] Indoor air, https://www.health.ny.gov/environmental/air_quality/#indoor_air New York State Department of Health
[4] Environmental Toxins, Yale New Haven Health, http://yalenewhavenhealth.org/library/healthguide/en-us/illnessconditions/topic.asp?hwid=support/zp3217
[8] "Health Hazards of some Gases" Jack E. Peterson, P.E., CIH, Ph.D., May, 1987
"Good Up High Bad Nearby", EPA publication number EPA-451/K-03-001, June 2003 (available from the U.S. EPA)
US EPA, HEALTH EFFECTS of OZONE in the GENERAL POPULATION [PDF] , U.S. EPA retrieved 2022/05/24 original source https://www.epa.gov/ozone-pollution-and-your-patients-health/health-effects-ozone-general-population
Baabor, Marcos G., Pedro F. Vázquez, and José A. Soriano Sánchez. "Automated nucleotomy and nucleolysis with ozone." In Advances in Minimally Invasive Surgery and Therapy for Spine and Nerves, pp. 97-101. Springer Vienna, 2011.
Abstract: - research using ozone for medical treatment
Lumbar and radicular pain due to HNP has been described since 1934. It is thought that the pain is caused by compression and by other local chemical mediators that are present in the area of interaction between the root and the disc.
With the objective of treating patients suffering from this syndrome and with a percutaneous minimally invasive approach, we designed a mixed technique: percutaneous automated nucleotomy plus nucleolysis and periradicular infiltration with ozone.
A retrospective study of 105 patients was conducted, including 60 men and 45 women with an average age of 43 years. All patients were treated with that technique between November 2006 and August 2008. Clinical follow-up of 15.2 months was provided by telephone, utilizing a modified Mac Nab scale. The results were as follows: 60% excellent, 22.8% good (82.8% success), 9.6% acceptable, 7.6% poor.
From the eight patients that reported poor results, five were considered to have recurrent symptoms (4.8%), because they had initially shown a period of significant improvement post operatively. Morbidity was manifested by transient pain and muscle spasms in the post operative area (2.8%).
We conclude that this new mixed technique, compared to automated percutaneous nucleotomy alone, may be more widely utilized by broadening the indications, with acceptable results.
(Blocks Hernia Nucleolysis Nucleotomy Nucleus pulposus Ozone Percutaneous Radicular pain)
Castillejos, Margarita, Diane R. Gold, Andrew I. Damokosh, Paulina Serrano, George Allen, William F. McDonnell, Douglas Dockery, Silvia Ruiz Velasco, Mauricio Hernandez, and Carl Hayes. "Acute effects of ozone on the pulmonary function of exercising schoolchildren from Mexico City." American journal of respiratory and critical care medicine 152, no. 5 (1995): 1501-1507.
Abstract:
The acute effects of ozone (O3) on the change in lung function before and after exercise was assessed in 22 boys and 18 girls from 7 1/2 to 11 yr of age tested up to eight times over a 1 1/2-yr period outdoors (under a tarpaulin) at a school in Mexico City.
Ozone and particulates were monitored at an adjacent government station, in the school yard, and under the tarp.
Subjects were selected to oversample children with chronic respiratory symptoms, although children with active asthma under regular medication or FEV1 < 80% predicted were excluded.
Of the participants, 21 had chronic cough, chronic phlegm, or ever wheeze with colds or apart from colds.
Children performed two cycles of treadmill exercise (15 min) and rest (15 min) for a total of 1 h of intermittent exercise. Most subjects attained the target minute ventilation of 35 L/min/m2. Subjects exercised alternately during low ozone hours (8:00-10:00 A.M.) and during peak O3 hours (12:00-2:00 P.M.), to assure a range of exposures.
On 85% of exercise days, the maximum daily 1-h average for ambient O3 exceeded the Mexican guideline of 110 parts per billion (ppb). O3 exposure during the hour of exercise was divided into quintiles, and the response was adjusted for repeated measures, subject having a cold, and prior outdoor exercise.
Ambient O3 in the fifth quintile (mean = 229 ppb) was associated with a percentage change in FVC (-1.43% +/- 0.70), FEV1 (-2.85% +/- 0.79), FEF25-75% (-6.32 +/- 1.87) and FEV1 (-1.41% +/- 0.46). ...
Dorado-Martínez, Claudia, Cristina Paredes-carbajal, Dieter Mascher, Gabino Borgonio-Pérez, and Selva Rivas-arancibia. "Effects of different ozone doses on memory, motor activity and lipid peroxidation levels, in rats." International journal of neuroscience 108, no. 3-4 (2001): 149-161.
Abstract: Ozone is one of the main atmospheric pollutants. Its inhalation causes an increase in free radicals, when these free radicals are not compensated by antioxidants, it leads to an oxidative stress state. This oxidative stress state has been implicated in neurodegenerative processes.
To determine the effects of oxidative stress caused by exposure to ozone on memory and motor activity, we used 120 male Wistar rats exposed to one of the following ozone doses, (0.0, 0.1, 0.4, 0.7, 1.1 and 1.5 ppm), for four hours.
After ozone exposure, short and long term memory of a one trial passive avoidance test were measured, and motor activity was registered for five minutes, in 10 rats of each group. In 16 rats exposed to 0.0, 0.4, 0.7 or 1.1 ppm lipid peroxidation levels from frontal cortex, hippocampus, striatum and cerebellum, were measured.
Results show that ozone, causes memory impairment from doses of 0.7 ppm, decrease in motor activity from doses of 1.1 ppm, and increase in lipid peroxidation levels from doses of 0.4 ppm, that increase with the dose.
Golden, J. A., J. A. Nadel, and H. A. Boushey. "Bronchial Hyperirritability in Healthy Subjects after Exposure to Ozone 1, 2." American Review of Respiratory Disease 118, no. 2 (1978): 287-294.
Abstract:
We studied the effect of a 2-hour exposure to 0.6 ppm of ozone on bronchial reactivity in 8 healthy, nonsmoking subjects by measuring the increase in airway resistance (Raw) produced by inhalation of histamine diphosphate aerosol (1.6 per cent, 10 breaths). Before exposure to ozone, histamine increased the mean Raw from 1.2 to 1.8 cm H2O per liter per sec.
Immediately after exposure to ozone, the mean baseline Raw was unchanged, but the mean response to histamine was significantly greater than the pre-ozone response (Raw = 3.3 cm H2O per liter per sec; P<0.05).
For the group, this increase disappeared 1 day after exposure to ozone, although 2 subjects still had a significantly increased response to histamine for more than 1 week after exposure. In 4 subjects, pretreatment with atropine sulfate aerosol (0.1 to 0.2 mg per kg of body weight) blocked the increase in Raw produced by histamine after exposure to ozone.
We concluded that brief exposure to 0.6 ppm of ozone produces bronchial hyperirritability via cholinergic postganglionic pathways, probably by damaging airway epithelium and thereby sensitizing bronchial irritant receptors.
Gryparis, Alexandros, Bertil Forsberg, Klea Katsouyanni, Antonis Analitis, Giota Touloumi, Joel Schwartz, Evangelia Samoli et al. "Acute effects of ozone on mortality from the “air pollution and health: a European approach” project." American journal of respiratory and critical care medicine 170, no. 10 (2004): 1080-1087.
Abstract:
the Air Pollution and Health: A European Approach (APHEA2) project, the effects of ambient ozone concentrations on mortality were investigated.
Data were collected on daily ozone concentrations, the daily number of deaths, confounders, and potential effect modifiers from 23 cities/areas for at least 3 years since 1990. Effect estimates were obtained for each city with city-specific models and were combined using second-stage regression models.
No significant effects were observed during the cold half of the year.
For the warm season, an increase in the 1-hour ozone concentration by 10 μg/m3 was associated with a 0.33% (95% confidence interval [CI], 0.17–0.52) increase in the total daily number of deaths, 0.45% (95% CI, 0.22–0.69) in the number of cardiovascular deaths, and 1.13% (95% CI, 0.62–1.48) in the number of respiratory deaths.
The corresponding figures for the 8-hour ozone were similar.
The associations with total mortality were independent of SO2 and particulate matter with aerodynamic diameter less than 10 μm (PM10) but were somewhat confounded by NO2 and CO. Individual city estimates were heterogeneous for total (a higher standardized mortality rate was associated with larger effects) and cardiovascular mortality (larger effects were observed in southern cities).
The dose–response curve of ozone effects on total mortality during the summer did not deviate significantly from linearity.
Hazucha, Milan J., David V. Bates, and PHILIP A. Bromberg. "Mechanism of action of ozone on the human lung." Journal of Applied Physiology 67, no. 4 (1989): 1535-1541.
Abstract:
Fourteen healthy normal volunteers were randomly exposed to air and 0.5 ppm of ozone (O3) in a controlled exposure chamber for a 2-h period during which 15 min of treadmill exercise sufficient to produce a ventilation of approximately 40 l/min was alternated with 15-min rest periods.
Before testing an esophageal balloon was inserted, and lung volumes, flow rates, maximal inspiratory (at residual volume and functional residual capacity) and expiratory (at total lung capacity and functional residual capacity) mouth pressures, and pulmonary mechanics (static and dynamic compliance and airway resistance) were measured before and immediately after the exposure period.
After the postexposure measurements had been completed, the subjects inhaled an aerosol of 20% lidocaine until response to citric acid aerosol inhalation was abolished. All of the measurements were immediately repeated.
We found that the O3 exposure
1) induced a significant mean decrement of 17.8% in vital capacity (this change was the result of a marked fall in inspiratory capacity without significant increase in residual volume),
2) significantly increased mean airway resistance and specific airway resistance but did not change dynamic or static pulmonary compliance or viscous or elastic work,
3) significantly reduced maximal transpulmonary pressure (by 19%) but produced no changes in inspiratory or expiratory maximal mouth pressures, and
4) significantly increased respiratory rate (in 5 subjects by more than 6 breaths/min) and decreased tidal volume.
Hoek, Gerard, Paul Fischer, Bert Brunekreef, Erik Lebret, Peter Hofschreuder, and Marcel G. Mennen. "Acute effects of ambient ozone on pulmonary function of children in the Netherlands." American review of respiratory disease 147 (1993): 111-111.
Jörres, R., Dennis Nowak, and Helgo Magnussen. "The effect of ozone exposure on allergen responsiveness in subjects with asthma or rhinitis." American journal of respiratory and critical care medicine 153, no. 1 (1996): 56-64.
Abstract:
The aim of this study was to determine whether ozone enhances bronchial responsiveness to allergens in subjects with allergic asthma, or facilitates a bronchial response in subjects with allergic rhinitis.
Twenty-four subjects with mild stable allergic asthma, 12 subjects with allergic rhinitis without asthma, and 10 healthy subjects participated in the study. Subjects breathed 250 ppb ozone or filtered air (FA) for 3 h of intermittent exercise. Airway responsiveness to methacholine was determined 1 h before and after exposures, and allergen responsiveness 3 h after exposures.
We determined the concentration of methacholine (PC20FEV1) and the dose of allergen (PD20FEV1) producing a 20% fall in FEV1. In the subjects with asthma, FEV1 decreased by 12.5 +/- 2.2% (mean +/- SEM; p = 0.0001), PC20FEV1 of methacholine by 0.91 +/- 0.19 doubling concentrations (p = 0.0001) and PD20FEV1 of allergen by 1.74 +/- 0.25 doubling doses (p < 0.0001) after ozone compared with FA.
The changes in lung function, methacholine, and allergen responsiveness did not correlate with each other.
In the subjects with rhinitis, mean FEV1 decreased by 7.8% and 1.3% when ozone or FA, respectively, were followed by allergen inhalation (p = 0.035).
Therefore, our data suggest that short-term exposure to ozone can increase bronchial allergen responsiveness in subjects with mild allergic asthma or rhinitis.
Linn, William S., Ramon D. Buckley, Charles E. Spier, Raymond L. Blessey, Michael P. Jones, D. Armin Fischer, and Jack D. Hackney. "Health Effects of Ozone Exposure in Asthmatics 1–3." American Review of Respiratory Disease 117, no. 5 (1978): 835-843.
Lippmann, Morton. "Health effects of ozone a critical review." Japca 39, no. 5 (1989): 672-695.
Abstract:
Health and pollution control professionals and the general public need to develop a more complete understanding of the health effects of ozone (O3) because:
1) we have been unable to significantly reduce ambient O3 levels using current strategies and controls;
2) in areas occupied by more than half of the U.S. population, current peak ambient O3 concentrations are sufficient to elicit measurable transient changes in lung function, respiratory symptoms, and airway inflammation in healthy people engaged in normal outdoor exercise and recreational activities;
3) the effects of O3 on transient functional changes are sometimes greatly potentiated by the presence of other environmental variables; and
4) cumulative structural damage occurs in rats and monkeys exposed repetitively to O3 at levels within currently occurring ambient peaks, and initial evidence from dosimetry models and interspecies comparisons indicate that humans are likely to be more sensitive to O3 than rats.
The extent and significance of these effects, and the multibillion dollar costs of ambient O3 controls need to be considered in any future revisions of ambient standards and the Clean Air Act.
The transient effects of O3 are more closely related to cumulative daily exposure than to one hour peak concentrations, and future revisions of the ambient standard for O3 should take this into account.
The effects of long-term chronic exposure to O3 remain poorly defined, but recent epidemiologic and animal inhalation studies suggest that current ambient levels are sufficient to cause premature aging of the lungs.
More research is needed to determine the need for a standard with a seasonal or annual average concentration limit.
McDonnell, William F., Donald H. Horstman, M. J. Hazucha, E. Seal, E. D. Haak, S. A. Salaam, and D. E. House. "Pulmonary effects of ozone exposure during exercise: dose-response characteristics." Journal of applied physiology 54, no. 5 (1983): 1345-1352.
Abstract:
Because minimal data are available regarding the pulmonary effects of ozone (O3) at levels less than 0.27 ppm, six groups of healthy young males were exposed for 2.5 h to one of the following O3 concentrations: 0.0, 0.12, 0.18, 0.24, 0.30, or 0.40 ppm.
Fifteen-minute periods of rest and exercise (65 l/min minute ventilation) were alternated during the first 2 h of exposure. Coughing was observed at all levels of O3 exposure.
Small changes in forced-expiratory spirometric variables [forced vital capacity (FVC), forced expiratory volume in 1 s, and mean expiratory flow rate between 25 and 75% FVC] were observed at 0.12 and 0.18 ppm O3, and larger changes were found at O3 levels greater than or equal to 0.24 ppm.
Changes in tidal volume and respiratory frequency during exercise, specific airway resistance, the presence of pain on deep inspiration, and shortness of breath occurred at O3 levels greater than or equal to 0.24 ppm.
In conclusion, pulmonary effects of O3 were observed at levels much lower than that for which these effects have been previously described. Stimulation of airway receptors is probably the mechanism responsible for the majority of observed changes; however, the existence of a second mechanism of action is postulated.
Menzel, Daniel B. "Ozone: an overview of its toxicity in man and animals." (1984): 181-204.
Abstract:
Ozone is one of the most toxic and ubiquitous air pollutants. This review focuses on the toxic effects of ozone in animals and on the similarities and disimilarities between the toxic effects in animals and humans. The molecular basis for the toxicity of ozone is discussed, based on the vigorous oxidizing properties of ozone.
Despite the existence of anatomical differences between human, subhuman primate, and dog lungs versus common experimental rodent lungs, the anatomical lesion of ozone inhalation occurs at the functionally equivalent site of the junction between the conducting airway and the respiratory region.
Ciliated cells of the upper airways and the type 1 cell of the centriacinar region are most affected. Type 2 cell proliferation is a hallmark of ozone toxicity. A wide variety of biochemical and physiological changes have been noted in several animal species and in humans.
Considerable evidence for a free‐radical‐mediated or lipid peroxide‐mediated toxicity is evident, especially in the induction of the glutathione peroxidase system and the protective effects of vitamins C and E. Ozone appears to be a weak mutagen and to produce chromosomal abnormalities.
Defects in defense against airborne infection are present in animals, which are more susceptible to airborne infection after ozone exposure.
Epidemiological studies, however, fail to detect increased respiratory infections in humans due to ozone.
Despite the variety of toxic effects, few qualitative differences between species are apparent; rather, quantitative differences do occur. Ozone may thus be an ideal compound for quantitative extrapolation of toxicity from animals to humans.
Preisser, Alexandra M., Lygia T. Budnik, and Xaver Baur. "Health effects due to fumigated freight containers and goods: how to detect, how to act." International maritime health 63, no. 3 (2012): 133-139.
Abstract:
Headache, concentration and memory disorders, dizziness and nausea, skin irritation, respiratory distress, and muscle cramps — isolated or in various combinations — may be the result of acute or chronic intoxication by fumigants.
The occurrence of these symptoms in workers who are engaged in the opening and unloading of containers, unpacking of imported goods, ventilating of containers, or working on bulk carriers are urgent indications of intoxication by fumigants or other toxic chemical residues in the transported goods.
The severity of the disorder depends on the concentration and duration of exposure, distribution and release of the fumigant, its kinetics, the individual susceptibility of the person, as well as any simultaneous exposure to other toxic substances. Physical symptoms, acute and chronic health effects due to contact with fumigants, are complex and difficult to discover.
In this article we explain how to identify the guiding symptoms and describe the appropriate diagnostic steps and the prevention of such events on cargo vessels as well as in the logistics and the handling of imported goods.
Reed, Dwayne, Sally Glaser, and John Kaldor. "Ozone toxicity symptoms among flight attendants." American journal of industrial medicine 1, no. 1 (1980): 43-54.
Abstract:
Because of persistent complaints of ozone-toxicity type symptoms among crew members of commercial airlines, we undertook a survey to determine the extent of the problem and the associated flight factors. Self-reported questionnaires and flight diaries were completed by 1,330 flight attendants, (FAs) working for three different airlines.
Ozone-toxicity type symptoms were reported three or four times more frequently by FAs with airlines flying at high altitudes than by those with low-flying airlines.
When examined by characteristics of flights, the ozone-toxicity type symptoms were significantly associated with flight altitude, duration and type of aircraft, but not with years worked, sex, medical history, or home residence. Other symptoms indicative of fatigue or stress were mainly associated with flight duration.
While these indirect data cannot implicate ozone specifically, they offer evidence that ozone-related health problems do exist among a large proportion of FAs.
Scheel, Lester D., Olga J. Dobrogorski, John T. Mountain, Joseph L. Svirbely, and Herbert E. Stokinger. "Physiologic, biochemical, immunologic and pathologic changes following ozone exposure." Journal of applied physiology 14, no. 1 (1959): 67-80.
Abstract:
A detailed study of physiologic, biochemical, immunologic and pathologic changes resulting from acute and repeated acute injuries due to inhalation of ozone is reported.
This study defines the primary chemical reaction of ozone with constituents of the body, the response of the body to the presence of the toxic substance, the physiologic functional alterations produced by acute and repeated acute injuries due to inhalation of this gas and the pathology produced by these injuries in rabbits, mice and rats.
The data presented show that ozone reacts with the proteins of lung tissue to produce a severe cellular irritation which alters cell wall permeability and leads to severe pulmonary edema.
Repeated acute injuries are shown to cause the development of fibrosis of the bronchioles and alveolar ducts, which limits the reserve capacity of the lung by causing the Hering-Breuer reflex to stop inspiration before complete inhalation can take place. Immunologic and biochemical changes observed which are characteristic of this type of injury are reported.
It has been shown that ozone reacts in a random fashion with proteins to produce a heterogeneous antigen which will stimulate an antibody response in rabbits.
The antigen created was shown to have characteristics similar to denatured protein.
The severe limitation of pulmonary function by reduced tidal volume and edema and the resulting pathologic changes are reported and discussed.
U.S. Chamber of Commerce, Ozone National Ambient Air Quality Standards [PDF] (August 2017) position statement, retrieved 2017/08/19, original source: https://www.uschamber.com/issue-brief/ozone-national-ambient-air-quality-standards
U.S. EPA, HEALTH EFFECTS OF OZONE POLLUTION [PDF] retrieved 2017/08/19, original source: https://www.epa.gov/ozone-pollution/health-effects-ozone-pollution
Weschler, Charles J. "Ozone's impact on public health: contributions from indoor exposures to ozone and products of ozone-initiated chemistry." Environmental health perspectives (2006): 1489-1496.
See http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1626413/ - Abstract:
Objective: The associations between ozone concentrations measured outdoors and both morbidity and mortality may be partially due to indoor exposures to ozone and ozone-initiated oxidation products. In this article I examine the contributions of such indoor exposures to overall ozone-related health effects by extensive review of the literature as well as further analyses of published data.
Findings
Daily inhalation intakes of indoor ozone (micrograms per day) are estimated to be between 25 and 60% of total daily ozone intake. This is especially noteworthy in light of recent work indicating little, if any, threshold for ozone’s impact on mortality.
Additionally, the present study estimates that average daily indoor intakes of ozone oxidation products are roughly one-third to twice the indoor inhalation intake of ozone alone. Some of these oxidation products are known or suspected to adversely affect human health (e.g., formaldehyde, acrolein, hydroperoxides, fine and ultrafine particles). Indirect evidence supports connections between morbidity/mortality and exposures to indoor ozone and its oxidation products.
For example, cities with stronger associations between outdoor ozone and mortality tend to have residences that are older and less likely to have central air conditioning, which implies greater transport of ozone from outdoors to indoors.
Conclusions
Indoor exposures to ozone and its oxidation products can be reduced by filtering ozone from ventilation air and limiting the indoor use of products and materials whose emissions react with ozone. Such steps might be especially valuable in schools, hospitals, and childcare centers in regions that routinely experience elevated outdoor ozone concentrations.
We do not completely share Weschler's conclusions because ozone itself is so highly volatile that ozone molecules don't tend to hang around long in buildings - unless an ozone generator is left turned on in the building itself. It would seem that a significant number of complaints about "ozone" may in fact be generated by odors emanating from oxicized materials that were exposed to an overdose of ozone during building "treatment" for odors. - OPNION - DF.
Association of Home Appliance Manufacturers (AHAM) 1111 19th Street, NW, Suite 402, Washington, DC 20036, (202) 872-5955 www.aham.org [website] provides information on air cleaners on their AHAM-certified Clean Air Delivery Rate site at www.cadr.org
AHAM conducts four certification programs for each category - room air cleaners, room air conditioners, dehumidifiers and refrigerator/freezers. The air cleaner certification program is known as AC-1.
BELL, KARL A., WILLIAM S. LINN, MILAN HAZUCHA, JACK D. HACKNEY, and DAVID V. BATES. "Respiratory effects of exposure to ozone plus sulfur dioxide in Southern Californians and Eastern Canadians." American Industrial Hygiene Association Journal 38, no. 12 (1977): 696-706.
Bhatia, A. OZONE FOR IMPROVING INDOOR AIR QUALITY-MYTHS AND REALITIES [PDF] Continuing Education and Development, Inc.
9 Greyridge Farm Court
Stony Point, NY 10980
P: (877) 322-5800
F: (877) 322-4774
info@cedengineering.com
Excerpts: Vendors of ozone generators or air purifier devices generating
ozone sometimes use words like “activated oxygen,” “super oxygen,” “trivalent oxygen,”
“allotropic oxygen,” “saturated oxygen,” “mountain-fresh air,” or “energized oxygen”
when talking about ozone. These words give readers a false picture, by implying that
ozone is a “healthy kind of oxygen.”
This is untrue.
Independent studies by the Environmental Protection Agency (EPA), and others have
shown that these devices do not effectively destroy microbes, remove odor sources, or
reduce indoor pollutants within the allowable permissible concentration of ozone.
Although ozone is used effectively in water to destroy microbes, ozone in air must reach
extremely hazardous levels to effectively kill microbes.
... Ozone can adversely affect
indoor plants, and damage materials such as rubber, electrical wire coatings, and fabrics
and art work containing susceptible dyes and pigments (U.S. EPA, 1996a).
Boeniger MF, 1995. Use of Ozone Generating Devices to Improve Indoor Air Quality, J
Am. Ind. Hygiene Assoc, 56:590-598.
California Department of Health Services, Indoor Air Quality Program, 850 Marina Bay Parkway, Suite G365/EHL, Richmond, CA 94804. DHS-IAQ Program Assistance Line: (510) 620-2874, Fax: (510) 620-2825
California DHS, HEALTH HAZARDS OF OZONE-GENERATING AIR CLEANING DEVICES [PDF] State of California-Health and Welfare Agency, Department of Health Services,
Indoor Air Quality Section § Jed Waldman, Ph.D., Chief, Environmental Health Laboratory Branch, 850 Marina Bay Parkway, Richmond, CA 94804, 510-620-2874 § FAX: 916-440-4440
Web Search 07/29/2010 original source: http://www.cal-iaq.org/o3_fact.htm
Excerpt: Ozone-generating devices are being marketed to the public as a solution to indoor quality
problems. Ozone generators are available in three forms: in-duct units for central air systems, portable
indoor units, and personal units that are worn on the body. They are promoted as effective “air
purifiers”, especially to people sensitive to indoor air pollutants.
Manufacturers often refer to the
ozone as activated oxygen, trivalent oxygen or nature’s air purifier to suggest that it is safe. They
advertise ozone’s ability to oxidize indoor air pollutants and “leave only carbon dioxide, water, and
breathable oxygen.”
However, independent studies have shown that ozone generators do not
effectively destroy microbes, remove odor sources, or reduce indoor pollutants enough to provide any
health benefits. More alarming, these devices can generate excessive levels of ozone and may
contribute to eye and nose irritation or other respiratory health problems for users.
Cestonaro, Larissa Vivan, Ana Maria Marcolan, Luciana Grazziotin Rossato-Grando, Ana Paula Anzolin, Gabriela Goethel, Angélica Vilani, Solange Cristina Garcia, and Charise Dallazem Bertol. "Ozone generated by air purifier in low concentrations: friend or foe?." Environmental Science and Pollution Research 24 (2017): 22673-22678.
Destaillats, H., M. Sleiman, and W. J. Fisk. EVALUATION OF POLLUTANT EMISSIONS FROM PORTABLE AIR CLEANERS, FINAL REPORT TO CALIFORNIA AIR RESOURCES BOARD [PDF] Prepared for the California Air Resources Board and
the California Environmental Protection Agency
Research Division
PO Box 2815
Sacramento CA 95812 Contract 10-320 (2014). Indoor Environment Group
Energy Analysis and Environmental Impacts Department
Environmental Energy Technologies Division
Lawrence Berkeley National Laboratory
1 Cyclotron Road
Berkeley, CA 94720
December 2014
Excerpt: The study findings indicate that primary and secondary emissions from portable air
cleaners may lead to poor IAQ and associated health effects for a significant number of
Californians.
[5] Foarde et als, Development of a Method for Measuring Single-Pass Bioaerosol Removal Efficiencies of a Room Air Cleaner, page 223 Karin K. Foarde, James T. Hanley, David S. Ensor, and PeterRoessler http://www.aaar.org/ast_abst/v30n0212.htm
Foarde et als, Methodology to Perform Clean
Air Delivery Rate Type Determinations with Microbiological Aerosols, page
235 Karin K. Foarde, Eric A. Myers, James T. Hanley, David S. Ensor, and
Peter F. Roessler - http://www.aaar.org/ast_abst/v30n0213.htm
Health Canada, "Health Canada Advises the Public About Air Cleaners Designed to Intentionally Generate Ozone (Ozone Generators)", Health Canada, Canada 1999-19, February 5, 1999. hc-sc.gc.ca/english/protection/warnings/1999/99_62e.htm
The use of indoor ozone generators as air purifiers has steadily
increased over the past decade. Many ozone generators are marketed to consumers for their ability to eliminate odors and microbial agents and to improve
health.
In addition to the harmful effects of ozone, recent studies have shown
that heterogeneous and homogeneous reactions between ozone and some
unsaturated hydrocarbons can be an important source of indoor secondary
pollutants, including free radicals, carbonyls, carboxylic acids, and fine particles.
Experiments were conducted in one apartment and two detached single-family
dwellings in Austin, TX, to assess the effects of an ozone generator on indoor
secondary organic aerosol concentrations in actual residential settings.
Ozone
was generated using a commercial ozone generator marketed as an air purifier,
and particle measurements were recorded before, during, and after the release of
terpenes from a pine oil-based cleaning product. Particle number concentration,
ozone concentration, and air exchange rate were measured during each experiment.
Particle number and mass concentrations increased when both terpenes
and ozone were present at elevated levels.
Experimental results indicate that
ozone generators in the presence of terpene sources facilitate the growth of
indoor fine particles in residential indoor atmospheres. Human exposure to
secondary organic particles can be reduced by minimizing the intentional release
of ozone, particularly in the presence of terpene sources.
Excerpts: A three-hour exposure to a personal air purifier resulted in a statistically significant reduction in pulmonary function among the whole study sample, as well as in the asthmatic subset (P LT 0.05) (n=10).
The mean reduction in FEV[sub] 1 /FVC ratio among the whole study sample was 9.6%, while it was 22.8% among the asthmatics.
One asthmatic individual experienced a 29% drop accompanied by a severe asthma attack.
...
Ozone-generating air purifiers and food purifiers that use ozone may impair pulmonary function.
Mainka, Anna, Walter Mucha, Józef S. Pastuszka, Ewa Brągoszewska, and Agnieszka Janoszek. NON-COMMERCIAL AIR PURIFIER—THE EFFECTIVENESS AND SAFETY [PDF] Buildings 10, no. 6 (2020): 104.
Abstract: (1) Background: On the Internet, we can find the guidelines for homemade air purifiers. One of the solutions includes the use of a low-cost ozone generator to decrease the level of odors and biological contaminants. However, the authors do not notify about hazardous effects of ozone generation on human health;
(2) Methods: We elaborated our test results on the bacterial and fungal aerosol reduction by the use of two technical solutions of homemade air purifiers. First, including a mesh filter and ozone generator, second including an ozone generator, mesh filter, and carbon filter.
(3) Conclusions: After 20 min of ozone generation, the concentration of bacteria decreased by 78% and 48% without and with a carbon filter, while fungi concentration was reduced in the lower range 63% and 40%, respectively.
Based on our test results, we proposed a precise periodical operation of homemade air purifier to maintain the permissible level of ozone for the occupants. View Full-Text
Keywords: IEQ; bioaerosols; airborne bacteria; airborne fungi; ozone; portable air purifier; ozone generation
Excerpts: 3.2. Ozone Concentrations
As can be seen in Figure 4, after 5 min of ozone generation, the concentration of O3 increased to the hazardous level of 420.7 μg/m3. After 20 min of ozone generation, the concentration of ozone decreases significantly (p = 0.02) compared to the concentration level consistent with 5 min of work.
This decrease is due to the decomposition time of ozone, which is approx. 20 min. Britigan et al. [27] pointed that O3 lifetime is moderately dependent on temperature variation and highly dependent on the presence of many reactive surfaces; for example, inside the car, the lifetime was only 2 min. In our study, after 20 min of air purification, the concentration of ozone remained at the level exceeding the acceptable O3 concentration (150 μg/m3) more than twice.
Therefore, we installed a carbon filter after the ozone generator to decrease the emission of ozone into the room. Figure 4 presents the reduction in ozone concentration with the use of a carbon filter. The installation of carbon filer significantly (p < 0.01) decreased the level of O3 in the air from 420.7 to 222.6 μg/m3 and from 382.2 to 239.8 μg/m3 after 5 min and 20 min of the ozone generator work without and with a carbon filter, respectively.
The concentration of ozone after 5 and 20 min of the ozone generator maintenance with carbon filter is not significantly different (p = 0.13), because the installation of carbon filter stabilizes the concentration of ozone.
4.2. Ozone Threat
It is well known that ozone due to its oxidative power supports the biological decontamination of environments. However, the careless usage of any ozone generator available on the market can be hazardous to the consumers.
[from Conclusions] Generally, there is a belief among users that if something is easy to buy, it is checked and safe for the user. Unfortunately, many easily accessible technologies can be harmful to users. Hence, further studies are necessary to compare different low-cost air filtration and purification products to develop meaningful outcomes regarding their impact on human health.
Nazaroff WW, and CJ Weschler, 2004. Cleaning products and air fresheners: Exposure
to primary and secondary air pollutants. Atmos Environ, 38, 2841-2865.
The manufacturers of ozone generators often claim that “safe” levels of ozone can
remove indoor air pollutants such as particles, gases, allergens, viruses, odorous
compounds, mold, and bacteria. In fact, ozone only reacts with some gases of concern
(aromatic hydrocarbons such as benzene) and with terpenes, such as limonene and
pinene. These reactions produce significant increases in other pollutants such as
formaldehyde and ultrafine particles, which can be harmful to health (Boeniger, 1995;
Nazaroff and Weschler, 2004; Hubbard et al., 2005).
U.S. EPA- Indoor Air Quality Information Clearinghouse (IAQ INFO), PO Box 37133, Washington D.C. 20013-7133; by phone (800) 438-4318.
U.S. EPA, OZONE GENERATORS THAT ARE SOLD AS AIR CLEANERS [PDF] retrieved 29022/05/24 original source: https://www.epa.gov/indoor-air-quality-iaq/ozone-generators-are-sold-air-cleaners#:~:text=Ozone can adversely affect indoor,(U.S. EPA 1996a).
Excerpt: Ozone can adversely affect indoor plants, and damage materials such as rubber, electrical wire coatings and fabrics and art work containing susceptible dyes and pigments (U.S. EPA, 1996a).
U.S. Environmental Protection Agency (US EPA). 1995. Ozone Generators in Indoor Air Settings. Report prepared for the Office of Research and Development by Raymond Steiber. National Risk Management Research Laboratory. U.S. EPA. Research Triangle Park. EPA-600/R-95-154.
U.S. Environmental Protection Agency (US EPA). 1996. Air Quality Criteria for Ozone and Related Photochemical Oxidants. Research Triangle Park, NC: National Center for Environmental Assessment-RTP Office; report nos. EPA/600/P-93/004aF-cF, 3v. NTIS, Springfield, VA; PB-185582, PB96-185590 and PB96-185608.
U.S. Environmental Protection Agency (US EPA). 1996. Review of National Ambient Air Quality Standards for Ozone: Assessment of Scientific and Technical Information. OAQPS Staff Paper. Office of Air Quality Planning and Standards. Research Triangle Park. NC. EPA-452/R-96-007.
U.S. Clean Air Act - large PDF - epw.senate.gov/envlaws/cleanair.pdf
Vincent, Renaud, Stephen G. Bjarnason, I. Y. Adamson, Charmaine Hedgecock, Prem Kumarathasan, Josee Guénette, Marc Potvin, Patrick Goegan, and Leo Bouthillier. "Acute pulmonary toxicity of urban particulate matter and ozone." The American journal of pathology 151, no. 6 (1997): 1563.
"Ozone-Generating Air Cleaners and Indoor Air Chemistry" , U.S. Environmental Protection Agency, original document is available at: epa.gov/appcdwww/iemb/ozone.htm
"Ozone Generators that are Sold as Air Cleaners", U.S. Environmental Protection Agency, original document is available at: epa.gov/iaq/pubs/ozonegen.html "EPA reviewed a wide assortment of this literature, including information provided by a leading manufacturer of ozone generating devices.
In keeping with EPA's policy of insuring that the information it provides is based on sound science, only peer reviewed, scientifically supported findings and conclusions were relied upon in developing this document."
The American Lung Association has an Air Cleaning Device fact sheet www.lungusa.org/air/air00_aircleaners.html
Vincent, Renaud, Stephen G. Bjarnason, I. Y. Adamson, Charmaine Hedgecock, Prem Kumarathasan, Josee Guénette, Marc Potvin, Patrick Goegan, and Leo Bouthillier. "Acute pulmonary toxicity of urban particulate matter and ozone." The American journal of pathology 151, no. 6 (1997): 1563.
Yoda, Yoshiko, Kenji Tamura, Sho Adachi, Naruhito Otani, Shoji F. Nakayama, and Masayuki Shima. "Effects of the use of air purifier on indoor environment and respiratory system among healthy adults." International journal of environmental research and public health 17, no. 10 (2020): 3687.
Zhang, Y., Mo, J., Li, Y., Sundell, J., Wargocki, P., Zhang, J., Little, J.C., Corsi, R.,
Deng, Q., Leung, M.H.K., Fang, L., Chen, W., Li,J., Sun, Y. Can commonly-used
fan-driven air cleaning technologies improve indoor air quality? A literature
review. Atmos. Environ. 2011, 45, 4329-4343.
Excerpts
... sorption of some gaseous pollutants (VOCs, formaldehyde, O3, NO2, SO2, and
H2S) is efficient if the system is properly designed and operated, but it may
produce byproducts if ozone reacts with adsorbed contaminants [p. 16]
a. Extremely high ozone emissions were observed in Phase 1 and Phase 2 (~160
ppb), significantly higher than those claimed by manufacturer (90 ppb) (Figures
4.3.1 – 4.3.3)
b. A partial reduction in VOC concentrations was observed in Phase 2, with moderate
reduction of most VOCs but almost complete depletion of the two alkenes
(limonene and styrene), which are very reactive with ozone (Figures 4.3.4 – 4.3.5)
c. Formation of ultrafine particles during Phase 2, ~6 times higher than background
levels, likely due to reaction of ozone with alkenes (Figures 4.3.6 – 4.3.8)
-- [p. 41]
References for using ozone for drinking water disinfection
Arnold, Benjamin F., and John M. Colford Jr. "Treating water with chlorine at point-of-use to improve water quality and reduce child diarrhea in developing countries: a systematic review and meta-analysis." American journal of tropical medicine and hygiene 76, no. 2 (2007): 354-364.
Lazarova, V., Ph Savoye, M. L. Janex, E. R. Blatchley III, and M. Pommepuy. "Advanced wastewater disinfection technologies: state of the art and perspectives." Water Science and Technology 40, no. 4 (1999): 203-213.
Peeters, JOHAN E., E. Ares Mazas, Willy J. Masschelein, I. Villacorta Martiez de Maturana, and Emile Debacker. "Effect of disinfection of drinking water with ozone or chlorine dioxide on survival of Cryptosporidium parvum oocysts." Applied and environmental microbiology 55, no. 6 (1989): 1519-1522. Abstract:
Demineralized water was seeded with controlled numbers of oocysts of Cryptosporidium parvum purified from fresh calf feces and subjected to different treatments with ozone or chlorine dioxide. The disinfectants were neutralized by sodium thiosulfate, and neonatal mice were inoculated intragastrically and sacrificed 7 days later for enumeration of oocyst production.
Preliminary trials indicated that a minimum infection level of 1,000 oocysts (0.1-ml inoculum) per mouse was necessary to induce 100% infection. Treatment of water containing 10(4) oocysts per ml with 1.11 mg of ozone per liter (concentration at time zero [C0]) for 6 min totally eliminated the infectivity of the oocysts for neonatal mice.
A level of 2.27 mg of ozone per liter (C0) was necessary to inactivate water containing 5 x 10(5) oocysts per ml within 8 min. Also, 0.4 mg of chlorine dioxide per liter (C0) significantly reduced infectivity within 15 min of contact, although some oocysts remained viable.
Schoenen, D. "Role of disinfection in suppressing the spread of pathogens with drinking water: possibilities and limitations." Water research 36, no. 15 (2002): 3874-3888.
Shin, Gwy-Am, and Mark D. Sobsey. "Inactivation of norovirus by chlorine disinfection of water." Water research 42, no. 17 (2008): 4562-4568.
Sobsey, Mark D., Sanitation Water, and World Health Organization. "Managing water in the home: accelerated health gains from improved water supply/prepared by Mark D. Sobsey." (2002).
Xu, Xiaoming, Philip S. Stewart, and Xiao Chen. "Transport limitation of chlorine disinfection of Pseudomonas aeruginosa entrapped in alginate beads." Biotechnology and bioengineering 49, no. 1 (1996): 93-100.
Research on Using Ozone in Mold Remediation
Includes research on and warnings about ozone damage to building or vehicle materials or contents.
Bertol, Charise D., Karoline Pissolatto Vieira, Luciana Grazziotin Rossato, and Juliano V. D'Avila. "Microbiological environmental monitoring after the use of air purifier ozone generator." Ozone: science & engineering 34, no. 3 (2012): 225-230.
Abstract: The work aimed to evaluate the indoor microbiological air quality after using the purifier ozone generator (Brizzamar®), by counting the total viable microorganisms. The plates containing the culture media were exposed on pre-defined locations for 10 min at the times 0 h (without purifier), 1, 2 and 3 h (with purifier).
The results showed significant decreases in the microorganisms after using the purifier, reaching a reduction up to 80% of the fungi and bacteria in the environment after two hours. The amount of ozone in the atmosphere was kept at 0,01 ppm, which is considered non-toxic to human exposure.
The purifier significantly improved the air quality in indoors.
Foarde, K. K., D. W. VanOsdell, and R. S. Steiber. "Investigation of gas-phase ozone as a potential biocide." Applied Occupational and Environmental Hygiene 12, no. 8 (1997): 535-542.
Abstract: Ozone has been used as a germicidal agent for drinking water since 1903, and its activity in the aqueous phase is well documented.
However, despite the wide use of ozone generators for indoor air treatment, there is little research data on ozone's biocidal activity in the gas phase. This article presents experimental data on the effect of ozone on both vegetative and spore-forming fungi as well as a spore-forming bacterium.
Dried suspensions of the test organisms were exposed to a range of ozone concentrations from 3 to 10 ppm in 50-L Teflon-coated stainless steel chambers. A two-phase study was performed.
The first phase was an extensive series of tests on the efficacy of ozone itself. Tests using organisms deposited on glass slides to minimize losses of ozone were carried out under conditions of high (90%) and low (30%) relative humidity (RH). For the organisms used in this study, ozone concentrations in the range of 6 to almost 10 ppm were required for significant kill. Organisms exposed under high RH conditions were generally more susceptible to ozone.
The second phase of tests employed actual building materials as the test surfaces. No microbial kill was demonstrated on any of the building materials even at 9 ppm ozone.
Franken, Laurence. THE APPLICATION OF OZONE TECHNOLOGY FOR PUBLIC HEALTH AND INDUSTRY [PDF] Population (2001). Food Safety & Security at Kansas State University, (November 2005) , retrieved 2022/05/22 original source: http://www.breathe-easier.com/research/Franken20051103.pdf
Excerpt … “Ozone is a strong oxidizer that will accelerate the
degradation of rubber, upholstery, paints, and other
materials. Thus, even when used in unoccupied areas,
ozone generators can cause damage to building
materials and electronic devices (“Hazards of ozone”,
1998).”
Typically, restoration companies which use
high level ozone generators recommend covering of
household product that might be affected by the
ozone. ” …
Editor's note: Watch out: as we have found evidence ozone-oxidation of carpets, carpet padding, and painted surfaces of walls and ceilings, as well as household furnishings such as foam-cushioned upholstered furniture, the suggestion that ozone-damage to building materials or contents can be avoided by covering these surfaces is impractical.
Gołofit-Szymczak, Małgorzata, Agata Stobnicka-Kupiec, and Rafał L. Górny. "Impact of air-conditioning system disinfection on microbial contamination of passenger cars." Air Quality, Atmosphere & Health 12, no. 9 (2019): 1127-1135.
Guo, Chao, Zhi Gao, and Jialei Shen. "Emission rates of indoor ozone emission devices: A literature review." Building and Environment 158 (2019): 302-318.
Abstract:
As a strong oxidizing gas, ozone can damage the human respiratory tract and cardiovascular system. Aside from ambient outdoor ozone that enters buildings, indoor ozone emission devices (IOEDs) such as disinfectors, air purifiers, and printing devices are the primary source of indoor ozone.
This review briefly presents the types and ozone emission mechanisms of IOEDs, the setups and procedures for measuring the ozone emission rate (OER) of IOEDs, and various equations for analyzing test results.
This review also summarizes and compares the OERs of different IOEDs and analyzes the factors affecting the OER. The average OERs of in-duct air cleaners, ozone generators, room air purifiers, photocopiers, laser printers, and other small household devices are 62.8, 76.3, 4.6, 3.3, 0.8, and 0.4 mg/h, respectively.
The OERs of in-duct air cleaners and ozone generators are generally larger than those of printing devices.
The highest and lowest OERs of room air purifiers in the surveyed literature are 30.5 mg/h and 56 μg/h, respectively, with a difference of approximately 550 times.
The ozone emission per unit paper for printing devices and per kilowatt hour for other IOEDs are also calculated and compared. In addition, the effects of the design and working mechanism of IOEDs on the OER are also discussed in detail.
Users' operation and daily maintenance of an IOED and the OER test conditions can also affect the OER. Finally, analytical equations are used to compare the influence of the test result processing method on the OER for the same IOED.
The use of indoor ozone generators as air purifiers has steadily
increased over the past decade. Many ozone generators are marketed to consumers for their ability to eliminate odors and microbial agents and to improve
health.
In addition to the harmful effects of ozone, recent studies have shown
that heterogeneous and homogeneous reactions between ozone and some
unsaturated hydrocarbons can be an important source of indoor secondary
pollutants, including free radicals, carbonyls, carboxylic acids, and fine particles.
Experiments were conducted in one apartment and two detached single-family
dwellings in Austin, TX, to assess the effects of an ozone generator on indoor
secondary organic aerosol concentrations in actual residential settings.
Ozone
was generated using a commercial ozone generator marketed as an air purifier,
and particle measurements were recorded before, during, and after the release of
terpenes from a pine oil-based cleaning product. Particle number concentration,
ozone concentration, and air exchange rate were measured during each experiment.
Particle number and mass concentrations increased when both terpenes
and ozone were present at elevated levels.
Experimental results indicate that
ozone generators in the presence of terpene sources facilitate the growth of
indoor fine particles in residential indoor atmospheres.
Human exposure to
secondary organic particles can be reduced by minimizing the intentional release
of ozone, particularly in the presence of terpene sources.
Practical Implications
Past studies have shown that ozone-initiated indoor chemistry can lead to elevated concentrations of fine particulate
matter, but have generally been completed in controlled laboratory environments and office buildings.
We explored
the effects of an explicit ozone generator marketed as an air purifier on the formation of secondary organic aerosol
mass in actual residential indoor settings.
Results indicate significant increases in number and mass concentrations for
particles less than 0.7 microns in diameter, particularly when an ozone generator is used in the presence of a terpene source
such as a pine oil-based cleaner.
These results add evidence to the potentially harmful effects of ozone generation in
residential environments.
Hudson, James B., and Manju Sharma. "The practical application of ozone gas as an anti-fungal (anti-mold) agent." Ozone: science & engineering 31, no. 4 (2009): 326-332.
Abstract:
We evaluated the ability of a portable ozone generating machine (Viroforce 1000) to inactivate 13 different species of environmental fungi. Samples, prepared as wet or dried films, were subjected to one or two cycles of treatment (35 ppm ozone for 20 minutes, with a short burst of >90% relative humidity), and measured for residual viability.
Treatments could inactivate 3 log10 cfu (colony forming units) of most of the fungi, both in the laboratory and in simulated field conditions, on various surfaces. We conclude that the ozone generator would be a valuable decontamination tool for mold removal in buildings.
Editor's note: Watch out: while the conclusion of the authors may be based on credible research, using ozone generators improperly damages building or vehicle materials and can result in significant additional costs to replace those items as well as potential health effect on building or vehicle occupants exposed to offgassing of oxidized materials - Ed.
Korzun, William, Jeffery Hall, and Ronald Sauer. "The effect of ozone on common environmental fungi." American Society for Clinical Laboratory Science 21, no. 2 (2008): 107-111.
Excerpt:
CONCLUSIONS: These data suggest that ozone must be used in conjunction with other methods of remediation or for more prolonged exposure times in order to eliminate fungal contamination of buildings.
Lamorena, Rheo B., and Woojin Lee. "Influence of ozone concentration and temperature on ultra-fine particle and gaseous volatile organic compound formations generated during the ozone-initiated reactions with emitted terpenes from a car air freshener." Journal of Hazardous Materials 158, no. 2-3 (2008): 471-477.
Abstract:
Experiments were conducted to identify the emissions from the car air freshener and to identify the formation of ultra-fine particles and secondary gaseous compounds during the ozone-initiated oxidations with emitted volatile organic compounds (VOCs).
The identified primary constituents emitted from the car air freshener in this study were α-pinene, β-pinene, p-cymene, and limonene. Formation of ultra-fine particles (4.4–160 nm) was observed when ozone was injected into the chamber containing emitted monoterpenes from the air freshener.
Particle number concentrations, particle mass concentrations, and surface concentrations were measured in time dependent experiments to describe the particle formation and growth within the chamber. The irritating secondary gaseous products formed during the ozone-initiated reactions include formaldehyde, acetaldehyde, acrolein, acetone, and propionaldehyde.
Ozone concentration (50 and 100 ppb) and temperature (30 and 40 °C) significantly affect the formation of particles and gaseous products during the ozone-initiated reactions.
The results obtained in this study provided an insight on the potential exposure of particles and irritating secondary products formed during the ozone-initiated reaction to passengers in confined spaces.
Lee, David S., Michael R. Holland, and Norman Falla. "The potential impact of ozone on materials in the UK." Atmospheric Environment 30, no. 7 (1996): 1053-1065.
Abstract:
Recent reports have highlighted the potential damage caused to a range of media, including materials, by ozone (O3).
The limited data available indicate significant damage to rubber products and surface coatings but either insignificant or unquantifiable damage to textiles and other polymeric materials at the range of atmospheric concentrations encountered in the U.K.
Materials in the indoor environment have been excluded from economic analyses.
Legislation was put in place in 1993 in the U.K. in order to reduce NOx (NOx = NO + NO2) and VOC (volatile organic compounds) emissions from motor vehicles which is likely to result in reduced peak O3 episodes but increased average levels of O3 in urban areas which may result in increased damage to materials.
A detailed assessment of the costs of O3 damage to materials is not currently possible because of insufficient information on relevant dose-response functions and the stock at risk.
Alternative methods were thus adopted to determine the potential scale of the problem.
Scaling of U.S. estimates made in the late 1960s provides a range for the U.K. of £170 million-£345 million yr−1 in current terms. This includes damage to surface coatings and elastomers, and the cost of antiozonant protection applied to rubber goods. Independent estimates were made of the costs of protecting rubber goods in the U.K.
These were based on the size of the antiozonant market, and provide cost ranges of £25 million-£63 million yr−1 to manufacturers and £25 million-£189 million yr−1 to consumers. The only rubber goods for which a damage estimate (not including protection costs) could be made were tyres, using data from the U.S.A. and information on annual tyre sales in the U.K. A range of £0-£4 million yr−1 was estimated.
The cost of damage to other rubber goods could not be quantified because of a lack of data on both the stock at risk and exposure-response functions. The effect of O3 on the costs of repainting were estimated under scenarios of increased urban concentrations of O3 using damage functions derived from the literature. The cost was estimated to be in the range of £0-£60 million yr−1 for a change from 15 to 20 ppb O3, and £0 to £182 million yr−1 for a change from 15 to 30 ppb O3.
The wide ranges derived for effects on surface coatings are a reflection of the uncertainty associated with the dose-response functions used.
Massey, S. W. "The effects of ozone and NOx on the deterioration of calcareous stone." Science of the total environment 227, no. 2-3 (1999): 109-121.
Mendez-Jimenez, David, Pascale SJ Lakey, Manabu Shiraiwa, and Heejung Jung. "Behavior of carbon monoxide, nitrogen oxides, and ozone in a vehicle cabin with a passenger." Environmental Science: Processes & Impacts 23, no. 2 (2021): 302-310.
Abstract:
Drivers and passengers are exposed to high concentrations of air pollutants while driving. While there are many studies to assess exposure to air pollutants penetrating into a vehicle cabin, little is known about how individual gas pollutants are behaving (e.g. accumulating, depositing, reacting etc.) in the cabin.
This study investigated the characteristic behavior of CO, NO, NO2 and O3 in a vehicle cabin in the presence of a driver with static, pseudo dynamic and dynamic tests.
We found in our experiments that CO and NO concentrations increased while O3 and NO2 concentrations decreased rapidly when cabin air was recirculated.
A kinetic model, which contains 20 chemical reactions, could predict the static test results well. CO and NO accumulations in the cabin were due to exhalation from the driver and conversion of NO2 to NO upon deposition to surfaces may also play a role. Pseudo dynamic and dynamic test results showed similar results.
During the fresh air mode CO, NO, and NO2 followed similar trends between the inside and outside of the cabin, while in cabin O3 concentrations were lower compared to outside concentrations due to reactions with the human and surface deposition.
The Cabin Air Quality Index approached 0.8 and 0.4 for O3 during pseudo dynamic and dynamic tests, respectively. Accumulation of NO in the cabin was not obvious during the dynamic test due to a large variation of outside NO concentrations.
We encourage auto manufacturers to develop control algorithms and devices to reduce a passenger's exposure to gaseous pollutants in vehicle cabins.
McClurkin, J. D., and D. E. Maier. "Half-life time of ozone as a function of air conditions and movement." Julius-Kühn-Archiv 425 (2010): 381.
Peitzsch, Mirko, Erica Bloom, Rocco Haase, Aime Must, and Lennart Larsson. "Remediation of mould damaged building materials—efficiency of a broad spectrum of treatments." Journal of Environmental Monitoring 14, no. 3 (2012): 908-915.
Abstract
We compared the efficiency of some commercially available products and methods used for remediation of mould-contaminated building materials. Samples of gypsum board and pinewood were artificially contaminated with toxin-producing isolates of Stachybotrys chartarum and Aspergillus versicolor, respectively, then, ten different remediation treatments were applied according to the manufacturers' instructions.
Microbial and chemical analyses of the infested materials were carried out both immediately before and after treatment, after six weeks of drying at room temperature, and after another six weeks of remoistening.
The aim of the study was to determine whether the investigated methods could inhibit the mould growth and destroy some selected mycotoxins produced by the moulds. None of the decontamination methods tested could completely eliminate viable moulds.
Some methods, especially boron based chemicals, ammonium based chemicals, and oxidation reduced the contents of mycotoxins produced by S. chartarum (satratoxin G and H, verrucarol), whereas the one which uses an ammonium based chemical reduced the amount of sterigmatocystin produced by A. versicolor with statistical significance. No remediation treatment eliminated all the toxins from the damaged materials.
These results emphasize the importance to work preventively with moisture safety throughout the construction processes and management to prevent mould growth on building materials.
[7] Canada DHS, Ozone as an oxidant, a few references from the Canadian Government
Bogaty, H., Campbell K. S., and Appel, W. D. (1952). The oxidation of cellulose by ozone in small concentrations. Text. Res. J. 22: 81-83.
Bradley,
C. E., and Haagen-Smit, A. J. (1951). The application of rubber in the
quantitative determination of ozone. Rubber Chem. Technol. 24: 750-755.
Cass, G. R., Nazaroff, W. W., Tiller, C., and Whitmore, P. M. (1991). Protection of
works of art from damage due to atmospheric ozone. Atmospheric Environment,
25A( 2): 441-451.
Druzik, J. R. (1985). Ozone: The Intractable Problem. We stern Association for Art
Conservation newsletter.
(vol.7, no. 3)
Research on Hydroxyl Generators as "Air Purifiers" or Cleaners
We have measured the concentration of hydroxyl radicals (OH) produced in the gas phase by a commercially available purifier for air and surfaces, using the time rate of decay of n-heptane added to an environmental chamber. The hydroxyl generator, an Odorox® BOSS™ model, produces the OH through 185-nm photolysis of ambient water vapor.
The steady-state concentration of OH produced in the 120 m3 chamber is, with 2σ error bars, (3.25 ± 0.80) × 106 cm−3.
The properties of the hydroxyl generator, in particular the output of the ultraviolet lamps and the air throughput, together with an estimation of the water concentration, were used to predict the amount of OH produced by the device, with no fitted parameters.
To relate this calculation to a steady-state concentration, we must estimate the OH loss rate within the chamber owing to reaction with the n-heptane and the 7 ppb of background hydrocarbons that are present.
The result is a predicted steady-state concentration in excellent agreement with the measured value. This shows we understand well the processes occurring in the gas phase during operation of this hydroxyl radical purifier.
Implications: Hydroxyl radical air purifiers are used for cleaning both gaseous contaminants, such as volatile organic compounds (VOCs) or hazardous gases, and biological pathogens, both airborne and on surfaces.
This is the first chemical kinetic study of such a purifier that creates gas-phase OH by ultraviolet light photolysis of H2O.
It shows that the amount of hydroxyls produced agrees well with nonparameterized calculations using the purifier lamp output and device airflow. These results can be used for designing appropriate remediation strategies.
Kawamoto, K., I. Sato, M. Yoshida, and S. Tsuda. "Air purifiers that diffuse reactive oxygen species potentially cause DNA damage in the lung." Alternative Medicine Review 17, no. 1 (2012): 20-21.
Excerpts: Several appliance manufacturers have recently released new type air purifiers that can disinfect bacteria, fungi and viruses by diffusing reactive oxygen species (ROS) into the air. In this study, mice were exposed to the outlet air from each of 3 air purifiers from different manufacturers CA, B, C), and the lung was examined for DNA damage, lipid peroxidation and histopathology to confirm the safety of these air purifiers.
Neither abnormal behavior during exposure nor gross abnormality at necropsy was observed. No histopathological changes were also observed in the lung. However, significant increase of DNA damage was detected by the comet assay in the lung immediately after the direct exposure for 48 hr to models A and B, and for 16 hr to model B.
As for model B, DNA migration was also increased by 2 hr exposure in a 1 m(3) plastic chamber but not by 48 hr exposure in a room (12.6 m(3)).
Model C did not cause DNA damage.
Lipid peroxidation and 8-hydroxy deoxyguanosine (8-OH-dG) was not increased under the conditions DNA damage was detected by the comet assay.
The present results revealed that some models of air purifiers that diffuse ROS potentially cause DNA damage in the lung although the mechanism was left unsolved. PMID: 21139343
Commentary
F
or many years various companies have sold home ionic air purifying machines or ozone generators that rely on the production of ozone or other prooxidant molecules to "clean the air," rather than filtering the air through activated carbon or high-efficiency particulate air (HEPA) filters.
The benefits of these units have been called into question, since the adverse effects of ozone are well known (ozone is a criteria air pollutant regulated by health-related federal and state standards). New types of air purifiers, which rely on the formation of reactive oxygen species (ROS) and their diffusion through the air, are being used for indoor air purification.
This study used three ROS-generating air purification machines with mice to see if any of the machines caused oxidative DNA damage. Machine A produced [O.sub.2]- and H+ clusters. Machine B produced nanoparticles of water with hydroxyl radicals. Machine C produced a water mist with hydroxyl radicals.
Both machines A and B resulted in rapid DNA damage. While ROS-generating air purifiers may clear the air of certain chemicals and microbes, DNA damage seems like a high price to pay for these benefits.
Kim, Kyu-Ho, Jong-Oh Kim, Yong-Hwan Lee, and Young-Hyung Kim. "IoT Air Purifier with Humidification Function Capable of Removing PM1. 0 Ultra-fine Dust." 한국정보기술학회논문지 19, no. 6 (2021): 49-55.
Singh, Atul P., Shivam Prateek Singh, Anjali Singh, Shubham Gupta, Virendra Raj, Sachin Kumar, Ravi Shankar, and Brijesh Kumar. "Application of air purifier drone to control air pollutants in domestic and industrial areas." In 2020 International Conference on Electrical and Electronics Engineering (ICE3), pp. 676-679. IEEE, 2020.
Szczotko, Maciej, Izabela Orych, Łukasz Mąka, and Jolanta Solecka. "A review of selected types of indoor air purifiers in terms of microbial air contamination reduction." Atmosphere 13, no. 5 (2022): 800.
Excepts: Here we report on controlled test chamber measurements conducted at the Illinois Institute of
Technology to measure the pollutant removal efficacy of a WINIX 5500-2 portable air purifier. The
product uses four stages of technologies:
(1) pre-filter,
(2) washable carbon filter,
(3) HEPA filter,
and
(4) PlasmaWave® hydroxyl generator.
The product has been tested by AHAM to have a clean
air delivery rate (CADR) of 243, 232, and 246 cfm for dust, smoke, and pollen particle size ranges
in the test and to meet AHAM ozone (O3) emission limits of less than 50 ppb in a test chamber.
... Based on these results, we estimate that for particles in the smoke and dust size range, the
PlasmaWave® technology does not affect the device CADR, but the technology does appear to
contribute to the total CADR for particles in the pollen size range.
Moreover, the PlasmaWave®
technology appears to function as an ion generator, as measured.
Given the potential for ionization
and other additive oxidizing technologies to initiate indoor chemical reactions (Collins and Farmer,
2021; Joo et al., 2021; Kim et al., 2017; Ye et al., 2021; Zeng et al., 2021), further testing should also
characterize the impact of this device on gas-phase organic compounds (e.g., VOCs, aldehydes,
etc.).
Example Ozone Generator Manuals & Operating Guides
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References focused on ozone applications, exposure limits & hazards are listed in the article above
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