Green-McKenzie, Judith, MD, MPH, FACOEM

Vrablik, Kevin A., MD, MPH, FACOEM

Lehigh Valley Health Network: LVHN Scholarly Works

Lehigh Valley Health Network LVHN Scholarly Works Department of Medicine What is a Potential Source of Ozone in the Health Care Environment? Kevin A. Vrablik MD, MPH, FACOEM Lehigh Valley Health Network, kevin.vrablik@lvhn.org Judith Green-McKenzie MD, MPH, FACOEM Follow this and additional works at: https://scholarlyworks.lvhn.org/medicine  Part of the Medical Sciences Commons Published In/Presented At Vrablik, K. A., & Green-McKenzie, J. (2016). What Is a Potential Source of Ozone in the Health Care Environment?.Journal Of Occupational And Environmental Medicine / American College Of Occupational And Environmental Medicine, 58(2), e54-e55. doi:10.1097/JOM.0000000000000626. This Article is brought to you for free and open access by LVHN Scholarly Works. It has been accepted for inclusion in LVHN Scholarly Works by an authorized administrator. For more information, please contact LibraryServices@lvhn.org. Copyright © 2016 American College of Occupational and Environmental Medicine. Unauthorized reproduction of this article is prohibited The Occupational Medicine Forum is prepared by the ACOEM Occupational andEnvironmental Medical Practice Committee and does not necessarily represent anofficial ACOEM position. The Forum is intended for health professionals and is notintended to provide medical or legal advice, including illness prevention, diagnosisor treatment, or regulatory compliance. Such advice should be obtained directlyfrom a physician and/or attorney.What Is a PotentialSource of Ozone in theHealth CareEnvironment?A hospital employee with pre-existingreactive airways disease reported theonset of upper airway irritation and wheez-ing when in close proximity to a deployedmobile ultraviolet (UV) room sterilizingdevice. Low-level ozone exposure was sus-pected as a contributing factor. An investi-gation was conducted in an effort to furtherevaluate the situation. The question waswhether this device would produce suffi-cient amounts of ozone to induce symptomsin an employee.Mobile UV room disinfection devi-ces, often employed in hospital settings,have been shown to be effective in reducingthe presence of pathogens. These devicesare increasingly being used as an adjunct tostandard cleaning and disinfection practicesin health care settings to dose an enclosedarea (ie, patient room, operating room, andso on) with high-intensity UV light utilizingspecial bulbs that typically emit only UV-Clight. They have been used in an effort tocombat hospital-acquired infections due tobacteria such as Clostridium difficile,Acinetobacter spp., Vancomycin-resistantenterococcus, and methicillin-resistantStaphylococcus aureus, as well as fungiand viruses.1 These devices are also effec-tive against the Ebola virus.2Ozone is the unstable triatomic allo-trope of oxygen first considered to exist in1785 by Van Marum and discovered bySchönbein in 1840. The molecular formulawas elucidated in 1865 by Soret.3 It has acharacteristic ‘‘clean,’’ ‘‘electrical’’ odor,which is often noticed after a thunderstorm.Ozone is created naturally either by UVradiation or high-energy static electricity(lightning), which ruptures the di-oxygendouble bond creating two oxygen-freeradicals, which then join with other di-oxy-gen molecules to create ozone. Ozone thennaturally decays back to oxygen with avariable half-life depending on temperatureand pressure. Because it is unstable, andcannot be stored, ozone is industrially man-ufactured at point-of-use by corona effect,UV light, or electrolysis, for use as anoxidant, deodorant, disinfectant, or bleach-ing agent. Ozone is also a byproduct ofelectrical arc welding processes, high-volt-age electrical equipment operations, andhigh-intensity UV light processes.4Ozone, ubiquitous in the Earth’s stra-tosphere, serves to protect the planet fromharmful solar UV-B and UV-C radiation.Both UV-B and UV-C can cause DNAdamage, dermatologic and ophthalmologicsequelae, and environmental deterioration.The stratospheric ozone ‘‘layer’’ filters allUV-C and approximately 90% of UV-Bradiation. Ground level, or tropospheric,ozone appears as smog via photochemicalproduction when oxygen is combined withpollutant nitrous oxides and volatileorganic compounds in the presence ofwarm, humid air, and solar UV radiation.It is then trapped in close proximity to theground by weather inversion phenomenaand can cause respiratory tract and mucusmembrane irritation and environmentaldamage.4The characteristic odor of ozone isreadily detectable by the human nose atvariable levels ranging anywhere from 1to 50 parts per billion (ppb) depending onindividual olfactory sensitivity to the mol-ecule.5 Minor irritant symptoms usuallyoccur when ozone levels exceed 0.1 partsper million (ppm). More serious symptomscan occur when levels are above 0.5 to1 ppm, and atmospheres with at least5 ppm ozone are considered immediatelydangerous to life and health (IDLH). Forthose reasons, the Occupational Safety andHealth Administration (OSHA) mandatedthat workplace ozone levels not exceed0.1 ppm averaged over an 8-hour workday (8-hr TWA). This mandate was basedon information from the National Instituteof Occupational Safety and Health. TheEnvironmental Protection Agency, via theClean Air Act and the National AmbientAir Quality Standards, set the atmosphericozone action level at 0.075 ppm 8-hourTWA.4,6With technological advances in pre-venting health care associated infections,the unintentional presence of ozone withinhealth care facilities is now more prevalent.Given that ozone is produced by intense UVlight processes, technologies that utilizeUV radiation, such as automated roomsterilizing devices, can potentially generateclinically significant ozone levels.7 Thelamps used in these devices are made toemit UV-C light in the 100 to 290 nm range,which is in the range where ozone is pro-duced. The characteristic odor of ozone wasnoted to be distinctly present while utilizingone of these devices in this environment.This finding is important because ozone is aknown respiratory and mucus membraneirritant, exerting its destructive oxidativepotential on the sensitive pulmonary epi-thelium. Those with pre-existing respirat-ory conditions may be more sensitive to theill effects of ozone and may have reactionsto levels far below the regulatory limits setby OSHA.8An ozone monitor with a detectionlimit, accuracy, and precision of 1.5 ppbwas used in this investigation. Monitoringrevealed baseline ozone levels inside thepatient room to be less than 1 ppb. When themobile UV device was actively deployed,ozone levels reached a maximum of6.0 ppb. Ozone levels were not measuredoutside the room, but the distinct odor ofozone was present during deployment.A quantitative risk analysis wasapplied. Assuming OSHA has set the Per-missible Exposure Limit (PEL) at 0.1 ppmto protect 98% of workers from harm, anestimated level of risk based on the ozonelevels recorded at this institution was cal-culated. The maximum ozone levelmeasured was 6 ppb, which is 17 timeslower than the OSHA PEL. If one expectsAt the time of this research, Dr Vrablik was aresident at the University of Pennsylvania Occu-pational Medicine Residency program. Thisproject was presented in poster format at the2014 American Occupational Health Confer-ence.The author would like to acknowledge TimothyDocherty, MBA, CIH, Director of OccupationalSafety Management at LVHN and Phil G.Lewis, MD, MPH for their assistance with thisproject.This research was supported in part by traininggrants from the National Institute of Occu-pational Safety and Health, grant number: 5-TO1-0H008628, and the Health Resources andServices Administration, grant number:D33HP25770-01-00.The authors have no conflicts of interest to declare.Address correspondence to: Kevin A. Vrablik, MD,MPH, FACOEM, Lehigh Valley Health Net-work, HealthWorks Allentown, 1243 S. CedarCrest Blvd., Allentown, PA 18103 (Kevin.Vrablik@lvhn.org).Copyright  2015 American College of Occu-pational and Environmental MedicineDOI: 10.1097/JOM.0000000000000626e54 JOEM  Volume 58, Number 2, February 2016OCCUPATIONAL MEDICINE FORUMCopyright © 2016 American College of Occupational and Environmental Medicine. Unauthorized reproduction of this article is prohibited a 2% ill effect, then based on the previousassumption, one can divide that percentageby 17 in order to derive an estimate of 12 in10,000 (or about 1:1000) individuals whomay potentially experience an ill effectfrom an ozone level of 6 ppb. Assumingthat the ozone levels outside the room werehalf that inside the room, then it might beexpected that as many as six employeeswho come in the vicinity of the deployeddevice could be adversely affected, givenan employee base of 10,000.Employing environmental controlscan limit hospital employee, patient, andvisitor exposure to the small amounts ofozone produced by these mobile high-intensity UV-C room-sterilizing devices.Setting the ventilation system to providenegative pressure inside the room, if avail-able, and taping the door jambs withpainter’s tape when the device is deployedwill help prevent leak of ozone outside ofthe room under treatment. Limitingemployee, patient, and visitor foot trafficin the area where and when the devices aredeployed will also reduce the potential forunexpected exposure to trace ozone.For occupational medicine phys-icians responsible for promoting and pre-serving the health and safety of hospitalemployees, this is one potential environ-mental health hazard that should be con-sidered. As technology advances toimprove health care and reduce hospital-acquired infections, more such hazards mayemerge. This case of an unintentionalhealth care employee ozone exposure isan example of the need for continued vig-ilance for environmental and other healthhazards on the part of occupationalmedicine physicians.Suggested Readings:NIOSH: Occupational Health Guide-line for Ozone. September 1978.http://www.cdc.gov/niosh/docs/81-123/pdfs/0476.pdf.NIOSH/IPCS: International Chemi-cal Safety Card – Ozone. April 26, 1993.http://www.cdc.gov/niosh/ipcsneng/neng0068.html.OSHA Ozone Chemical SamplingInformation.http://www.osha.gov/dts/chemicalsampling/data/CH_259300.html.California Environmental ProtectionAgency, Office of Environmental HealthHazard Assessment, Determination ofAcute Reference Exposure Levels forAirborne Toxicants, Acute Toxicity Sum-mary – Ozone, March 1999.http://oehha.ca.gov/air/acute_rels/pdf/10028156A.pdf.Kevin A. Vrablik, MD, MPH, FACOEMJudith Green-McKenzie, MD, MPH,FACOEMOccupational Medicine Physician, LehighValley Health Network, HealthWorks,Allentown, Pennsylvania (Dr Vrablik); andAssociate Professor, Division of Occu-pational Medicine, University of Pennsyl-vania Medical Center, Philadelphia,Pennsylvania (Dr McKenzie)REFERENCES1. Nerandzic MM, Thota P, Sankar CT, et al.Evaluation of a pulsed xenon ultravioletdisinfection system for reduction in healthcare-associate pathogens in hospital rooms. InfectControl Hosp Epidemiol. 2015;36:192–197.2. Sagripanti J, Lytle S. Sensitivity to ultravioletradiation of Lassa, vaccinia and Ebola virusesdried on surfaces. Arch Virol. 2011;156:489–494.3. Rubin MB. The history of ozone. The Schönbeinperiod, 1839–1868. Bull Hist Chem. 2001;26:40–56.4. US Environmental Protection Agency—Ozone.Available at: http://www.epa.gov/ozone/index.html. Accessed August 1, 2015.5. Ruth JH. Odor thresholds and irritation levels ofseveral chemical substances: a review. Am IndHyg Assoc J 1986; 47:A142–A151.6. ACGIH: Documentation of the Threshold LimitValues (TLVs) and Biological Exposure Indices(BEIs)—Ozone. Cincinnati, OH: American Con-ference of Governmental Industrial Hygienists;2001.7. Kowalski W. Ultraviolet Germicidal IrradiationHandbook: UVGI for Air and Surface Disinfec-tion. Berlin Heidelberg: Springer Science andBusiness Media; 2012. p. 135.8. Devlin RB, Raub JA, Folinsbee LJ. Health effectsof ozone. Sci Med. 1997;May/June:8–17.JOEM  Volume 58, Number 2, February 2016 What Is a Potential Source of Ozone in the Health Care Environment? 2015 American College of Occupational and Environmental Medicine e55

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