Xenon Lamp Disinfection Ozone Effects
Possible Ozone byproduct of Xenon disinfection system?
XENON LAMP OZONE OUTPUT? - CONTENTS: Reader asks about possible hazardous levels of gases including ozone & complains of chlorine odors when working in hospital where Xenon lamp disinfection system is used
POST a QUESTION or READ FAQs about using xenon lamp disinfection & ozone generators to kill odors or mold: dangers & false claims & about how to get rid of odors caused by ozone overdosing
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Xenon disinfection system output, gases, odor question:
At our hospital operating room we are using the Xenex® robot to kill C-diff and other bacterias harmful to staff and future patients. It smells like getting out of a highly chlorinated pool. This exceeds OSHA standards. How do I get the proper department to research this?
This article series discusses the problem of oxidation of building materials from excessive ozone exposure and the horrible chemical smells that may follow such mistakes. We describe how to track down which building materials were over-dosed with ozone and are now giving off a new stink, and we explain how to cure that problem. (Note: other uses of ozone as a disinfectant can be effective and are important in many applications.)
Ozone as Possible By-Product of Xenon Light Disinfection Methods
Reader Question: Xenex® robot in use for hospital disinfection seems to be producing high levels of ozone
31 August 2015 PhilB said:
At our hospital operating room we are using the Xenex® robot to kill C-diff and other bacterias harmful to staff and future patients.
Xenex claims their machine complies with OSHA regulations of .01ppm over an eight hour period. I have to run this ozone generating device 25+ times a night for ten minute cycles. There is a one minute grace period while the light retracts before I am alerted to reenter the room to move it to another spot. 2-3 shots per room every night.
Since I have been running this machine, I have a sore throat during my shift and my eyes burn at the end of the six hour burn-off.
Your article says,"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)."
It smells like getting out of a highly chlorinated pool.
This exceeds OSHA standards. How do I get the proper department to research this?
Reply: Xenon lamp disinfection is not itself an ozone treatment method but might produce ozone gas indoors
Phil, by your accounting you're running the equipment for more than four hours each night.
The Xenex® robot (Xenex Disinfection Services 121 Interpark,
Suite 104 San Antonio, TX 78216 Tel: 1-800-553-0069 Website: https://www.xenex.com/) is using "pulsed Xenon" a "UV" disinfection system.
While I'm no expert on UV disinfection by light in hospitals, it is apparent that the hazard and thus the short grace period, is a risk of exposure of the eyes to intense UV light. As long as the light is OFF when you enter the room, the light hazard would not be present. Material I've read on Xenon light disinfection cited no toxic byproducts. More clinical trials may be needed however to study the efficacy of the approach.
Xenon light disinfection is not an ozone disinfection method. Ozone disinfection uses a highly-reactive oxygen molecule O3 to oxidize materials. Xenon disinfection uses millisecond pules of an intense light at 200-320nm wavelength range for 8-12 minutes over 2-3 doses as its disinfection approach.
Ozone production and Xenon light has been discussed and the relationship between light in the UV range and ozone production has been cited by Salvermoser (2003 & 2008) and Schalk (2006) and others.
The influence of water vapor on photochemical ozone generation has been investigated. Tests of a coaxial ozone generator driven by an efficient, tubular, 172 nm xenon excimer lamp revealed that ozone saturation concentration strongly depends on moisture concentration in the process gas.
In order to adequately model the data, catalytic ozone destruction by OH and HO2 radicals formed by reactions with trace amounts of water vapor in the process gas had to be included in the photochemical ozone production rate equation system. Based on the model, optimized ozone photoreactor designs for ambient air, dry air and dry oxygen are described. (Salvermoser 2008)
Depending on the indoor moisture level, Xenon light can be a ozone generator and it seems to me ( a lay person ) that there could be hazards from Xenon light disinfection unless the proper bulb type is employed. The U.S. Army has made a clear and succincct remark on this concern:
Some types of UVGI lamps generate ozone. This can pose a workplace
hazard, and only “ozone free” lamps made with doped quartz should be used for
surface disinfection. - (U.S. Army Technical Paper 24-001-1114 2014)
And in the U.K. The Health and Safety Executive has commented on a related and potential hazard that is less immediatly obvious:
projection lamps: high-pressure xenon lamps used in cinema projectors emit some UV radiation and also produce ozone. (HSE Guidance Note #38, 2014)
What these suggest to me is that although Xenon disinfection is described by my earlier comments (and by expert research on the topic) it is possible that the procedure might be generating ozone in the area being treated. I suggest contacting Xenex directly to ask them for guidance on that question. I'm asking the company for advice directly as well. Let me know what you're told as what we learn may assist other readers.
(Sept 6, 2015) PhilB said:
When I spoke to the Xenex rep "Celia" she said the odor was ozone.
I sent an inquiry to Xenex through their website and a Mr. Ed Sylvester called me to explain they were within the legal limits of OSHA standards. 0.01ppm
However, in the above article it states ozone can be detected through the olfactory bulb between 0.02~0.05ppm. Now that is each and every time I use this machine 25+ times every night.
If my math were correct 25 x 0.03= 0.75ppm
(Sept 14, 2015) (mod) said:
Based on e-text alone we cannot know what the ozone level is in your building but in general, the sources I've reviewed on this question are in agreement that if you can smell ozone there is probably a higher-than-acceptable ozone level present.
You are right that the low-end of what people can smell is a very low level of ozone indoors - down to 0.02 ppm.
But because ozone is so volatile you cannot assume that it simply accumulates. Depending on the time period between ozone generation, the area volume, concentration and other factors, it is quite likely that by the end of the rest interval the ozone in the area where it was generated is at a much lower level, possibly below the limits of detection.
A more accurate picture is to assume that the ozone level is going up and down during the 15 usage cycles per night - presuming that they are all in the same physical area.
If the ozone is being generated each time in a new area then you cannot add them together to claim a higher exposure level.
But you can assert that if you smell ozone in the work area, you are being exposed to it repeatedly during a work shift. You don't know at what level unless it is measured during the entire time of exposure.
An industrial hygienist with expertise in ozone measurement and exposure standards would be the proper person to consult for an accurate on-site study of what's going on. Unfortunately that's also costly.
Research on relationship between Xenon lamp disinfection & ozone production
Eliasson, B., and U. Kogelschatz. "Ozone Generation with Narrow–Band UV Radiation." (1991): 365-373.
Abstract: Ozone formation in oxygen at atmospheric pressure following the photodissociation of O2 molecules in the vacuum UV range is tudied. A new VUV source based on incoherent xenon excimer radiation from a dielectric–barrier discharge provided narrow–band UV radiation at 172 nm with a half–width of 14 nm. The formation of ozone from the initial photodissociation fragments O(3P) and O(1D) is treated theoretically and compared to measurements.
EH40/2005 Workplace exposure limits: Containing the list of workplace
exposure limits for use with the Control of Substances Hazardous to Health
Regulations (as amended) Environmental Hygiene Guidance Note EH40
(Second edition) HSE Books 2011 ISBN 978 0 7176 6446 7
Health and Safety Executive, "Ozone: Health hazards and control
Guidance Note EH38",
EH38 (Third edition) Published 2014, HSE, U.K., retrieved 31 August 2015 original source: http://www.hse.gov.uk/pubns/eh38.pdf - Abstract: This guidance is primarily aimed at employers and managers of people
exposed to ozone in the course of their work. Other groups, such as
employees and health and safety professionals, will also find the guidance
It draws attention to the potential ill health which exposure to ozone can
cause and indicates potential sources of ozone at work as well as offering
advice on the precautions you may need to take to prevent or control
Pavlovich, Matthew J., Hung-Wen Chang, Yukinori Sakiyama, Douglas S. Clark, and David B. Graves. "Ozone correlates with antibacterial effects from indirect air dielectric barrier discharge treatment of water." Journal of Physics D: Applied Physics 46, no. 14 (2013): 145202.
Roth, J. Reece. Industrial Plasma Engineering: Volume 2-Applications to Nonthermal Plasma Processing. Vol. 2. CRC Press, 2001.
Salvermoser, Manfred, Daniel E. Murnick, and Ulrich Kogelschatz. "Influence of water vapor on photochemical ozone generation with efficient 172 nm xenon excimer lamps." Ozone: Science and Engineering 30, no. 3 (2008): 228-237.
Salvermoser, M., and D. E. Murnick. "High-efficiency, high-power, stable 172 nm xenon excimer light source." Applied physics letters 83, no. 10 (2003): 1932-1934.
Schalk, Sven, Volker Adam, Erich Arnold, Karl Brieden, Alex Voronov, and H. D. Witzke. "UV-lamps for disinfection and advanced oxidation–Lamp types, technologies and applications." IUVA news 8, no. 1 (2006): 32-37.
ozone is produced via 185 nm radiation in combination
with oxygen from ambient air, the UV/O3 process does not
necessarily need an external ozone source. In aqueous
solutions, the 185 nm radiation is absorbed almost
exclusively by water, bringing about its photolysis to yield
·OH radicals and ·H atoms.
... The preferred envelope material for Standard Low Pressure
Lamps is Fused Quartz. Due to the generally low wall
temperature, it is also possible to use Softglass (SodiumBarium-Glass).
Softglass Lamps have a similar design as
Fluorescent Lamps known from general lighting. The UVSoftglass
does not transmit at 185 nm, hence all these
lamps are “ozone-free” lamps.
In contrast to Softglass Lamps, standard Quartz Lamps are
available in both “ozone-free” (G, GPH lamps) and ozonegenerating
(G…VH, GPH…VH – VH stands for Very High
ozone) versions. As seen in Table 1, both the specific UVC-flux
per unit arc length and the UVC efficiency are higher for the
Fused Quartz types. This is caused by the lower transmittance
of Softglass compared to Fused Quartz at 254 nm.
Shintani, Hideharu, Akikazu Sakudo, Peter Burke, and Gerald McDonnell. "Gas plasma sterilization of microorganisms and mechanisms of action (Review)." Experimental and therapeutic medicine 1, no. 5 (2010): 731-738.
U.S. Army, "Effectiveness and Safety of
Ultraviolet Germicidal Irradiation Lamps Used for
Disinfecting Surfaces Contaminated with the Ebola Virus", Technical Information Paper No. 24-001-1114, retrieved 31 August 2015, original source http://phc.amedd.army.mil/PHC%20Resource%20Library/TIP_No_24-001-1114_Effectiveness_and_Safety_of_UVGI_Lamps.pdf Excerpt: Some types of UVGI lamps generate ozone. This can pose a workplace
hazard, and only “ozone free” lamps made with doped quartz should be used for
US Occupational Safety and Health Administration OSHA Analytical Methods
Manual 2nd Edition Method 10-214: Ozone in work place atmospheres
(impregnated glass fiber filter) USDOUOSHA Salt Lake City 1995
Wang, Ding, Thomas Oppenländer, Mohamed Gamal El‐Din, and James R. Bolton. "Comparison of the Disinfection Effects of Vacuum‐UV (VUV) and UV Light on Bacillus subtilis Spores in Aqueous Suspensions at 172, 222 and 254 nm." Photochemistry and photobiology 86, no. 1 (2010): 176-181.
Zoutman, Dick, The Pros and Cons of Alternative Disinfection Technologies for Room Decontamination (Powerpoint presentation), www.virox.com/files_docs/content/pdf/msds/CHICAPresentation4.pdf
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[1b] Jeff May - Jeffrey C May - May Indoor Air Investigations - Jeff is located in Tyngsborough, MA 01879 -
Phone • 978.649.1055 • 800.686.1055
[2b] "Health Hazards of Ozone-generating Air Cleaning Devices", 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
is not a substitute for mold removal and its reaction with building materials,
but applied by an expert may help deodorize, a cleaning article by Jim Holland -
 Ozone as an oxidant, a few references from the Canadian Government
H., Campbell K. S., and Appel, W. D. (1952). The oxidation of cellulose by ozone in small
concentrations. Text. Res. J. 22: 81-83.
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. Http://sul-server-2.stanford.edu/waac/wn/wn07/wn07-3/wn07-302.html
(vol.7, no. 3)
 "Health Hazards of some Gases" Jack E. Peterson, P.E., CIH, Ph.D., May, 1987
 Ozone Gas Hazards Description in our article
"Effects of Toxic Gas Exposure to Ammonia, Arsine Arsenic Bromine Carbon Dioxide Carbon Monoxide Hydride Ozone & others"
 "Laundry Ozone FAQ", Water Energy Laundry Consulting, 9741 Tappenbeck, Suite 1000, Houston, TX 77055 Tel: (713) 464-2580; web search 12/17/11, original source laundryconsulting.com/solution/
 "Ozone acting on human blood yields a hormetic dose-response relationship", Velio A Bocci, Iacopo Zanardi,& Valter Travagli, J Transl Med. 2011; 9: 66. Published online 2011 May 17. doi: 10.1186/1479-5876-9-66 - Quoting the article abstract:
The aim of this paper is to analyze why ozone can be medically useful when it dissolves in blood or in other biological fluids. In reviewing a number of clinical studies performed in Peripheral Arterial Diseases (PAD) during the last decades, it has been possible to confirm the long-held view that the inverted U-shaped curve, typical of the hormesis concept, is suitable to represent the therapeutic activity exerted by the so-called ozonated autohemotherapy. The quantitative and qualitative aspects of human blood ozonation have been also critically reviewed in regard to the biological, therapeutic and safety of ozone. It is hoped that this gas, although toxic for the pulmonary system during prolonged inhalation, will be soon recognized as a useful agent in oxidative-stress related diseases, joining other medical gases recently thought to be of therapeutic importance. Finally, the elucidation of the mechanisms of action of ozone as well as the obtained results in PAD may encourage clinical scientists to evaluate ozone therapy in vascular diseases in comparison to the current therapies.
 Petras T, Siems W, Grune T. 4-Hydroxynonenal is degraded to mercapturic acid conjugate in rat kidney. Free Radic Biol Med. 1995;19(5):685–688. doi: 10.1016/0891-5849(95)00060-B
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 detector-tubes and Drager accuro bellows pump, the Gastec cylinder pump
and detector-tube system produced by Gastec or Sensidyne, and
we also use Sensidyne's Gilian air pump. 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 our Gas Sampling Plan online document.
Kansas State University, department of plant pathology, extension plant pathology web page on wheat rust fungus: see http://www.oznet.ksu.edu/path-ext/factSheets/Wheat/Wheat%20Leaf%20Rust.asp
"A Brief Guide to Mold, Moisture, and Your Home",
U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
US EPA - Mold Remediation in Schools and Commercial Building [Copy on file at /sickhouse/EPA_Mold_Remediation_in_Schools.pdf ] - US EPA
US EPA - Una Breva Guia a Moho - Hongo [Copy on file as /sickhouse/EPA_Moho_Guia_sp.pdf - en Espanol
"IgG Food Allergy Testing by ELISA/EIA, What do they really tell us?" Sheryl B. Miller, MT (ASCP), PhD, Clinical Laboratory Director, Bastyr University Natural Health Clinic - ELISA testing accuracy: Here is an example of Miller's critique of ELISA
http://www.betterhealthusa.com/public/282.cfm - Townsend Letter for Doctors and Patients
The critique included in that article raises compelling questions about IgG testing assays, which prompts our interest in actually screening for the presence of high levels of particles that could carry allergens - dog dander or cat dander in the case at hand.
http://www.tldp.com/issue/174/IgG%20Food%20Allergy.html contains similar criticism in another venue but interestingly by the same author, Sheryl Miller. Sheryl Miller, MT (ASCP), PhD, is an Immunologist and Associate Professor of Basic and Medical Sciences at Bastyr University in Bothell, Washington. She is also the Laboratory Director of the Bastyr Natural Health Clinic Laboratory.
Allergens: Testing for the level of exposure to animal allergens is discussed at http://www.animalhealthchannel.com/animalallergy/diagnosis.shtml (lab animal exposure study is interesting because it involves a higher exposure level in some cases
Allergens: WebMD discusses allergy tests for humans at webmd.com/allergies/allergy-tests
Atlas of Clinical Fungi, 2nd Ed., GS deHoog, J Guarro, J Gene, & MJ Figueras, Centraalbureau voor Schimmelcultures, Universitat Rovira I Virgili, 2000, ISBN 90-70351-43-9 (you can buy this book at Amazon) - The Atlas of Clinical Fungi is also available on CD ROM
Atlas of Indoor Mold, Online Clinical Mold Atlas, Toxins, Pathogens, Allergens and Other Indoor Particles - Medical Health Effects of Mold (separate online document)
"A Brief Guide to Mold, Moisture, and Your Home", U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
"Disease Prevention in Home Vegetable Gardens,"
Department of Plant Microbiology and Pathology,
Department of Horticulture, University of Missouri Extension - extension.missouri.edu/publications/DisplayPub.aspx?P=G6202
Fifth Kingdom, Bryce Kendrick, ISBN13: 9781585100224, is available from the InspectAPedia online bookstore - we recommend the CD-ROM version of this book. This 3rd/edition is a compact but comprehensive encyclopedia of all things mycological. Every aspect of the fungi, from aflatoxin to zppspores, with an accessible blend of verve and wit. The 24 chapters are filled with up-to-date information of classification, yeast, lichens, spore dispersal, allergies, ecology, genetics, plant pathology, predatory fungi, biological control, mutualistic symbioses with animals and plants, fungi as food, food spoilage and mycotoxins.
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