Medical Devices ------------- Q's and A's
Q1. Does Health Canada have regulations on ozone generators?
A1. Yes. The Medical Devices Regulations 1 of the Food and Drugs Act place certain restrictions on the sale of ozone generators, but only if they are sold for medical purposes or make medical claims. Those which are not manufactured, sold or represented for therapeutic use are not subject to these regulations. (See background notes for more information.)
Q2. Are household air cleaners subject to the medical devices regulations?
A2. This depends on the type of claim being made or implied for the air cleaner. In general, such a product is considered a medical device if it is sold for the purpose of curing or preventing diseases, allergies or other health problems. In Canada, products which claim only to deodorize air, remove smoke and dust, and kill air-borne bacteria are not considered medical devices, and are therefore not subject to the regulations.
Q3. Are there federal regulations in Canada for ozone generators that are not medical devices?
A3. No, but Health Canada has published recommendations for maximum ozone levels in residential indoor air 2. The Acceptable Short Term Exposure Range (ASTER) is 120 parts per billion (ppb) averaged over one hour. (This recommendation is currently under review by Health Canada). Health Canada is also studying the safety of ozone generators which are not medical devices to determine whether regulations or guidelines should be developed for them.
Q4. What is ozone?
A4. Ozone is a form of oxygen. Its molecules consist of three oxygen atoms, designated by the chemical symbol O3. Ozone is unstable and decays rapidly to form regular oxygen molecules with two atoms (O2). It is continually created by lightning in the lower atmosphere and by solar ultraviolet rays in the upper atmosphere. The ozone layer in the upper atmosphere absorbs much of the ultra-violet radiation from the sun, and thus protects life on earth from these harmful rays. However, at ground level, ozone is generated by the action of sunlight on emissions from industry and vehicle exhaust, and is an air pollutant.
The level of ozone in outdoor air in Canadian cities is typically 15 ppb but varies seasonally, with higher values in the summer. Indoors, the level is usually lower but can be higher than outdoors if there are sources of ozone in the house 2.
Q5. What are the health effects of breathing ozone?
A5. Ozone is a powerful oxidizing agent and is highly toxic. In clinical studies, adverse effects have been observed in normal individuals at concentrations as low as 80 ppb. Concentrations of 2,000 to 4,000 ppb can cause irritation to the eyes within six minutes. Daily intermittent exposure to concentrations above 5,000 ppb can cause incapacitating lung congestion. Epidemiological and human clinical studies have shown a definite link between increases in outdoor ozone levels and increases in adverse health effects, including small lung function changes, inflammation, increases in respiratory symptoms, increased use of medication, visits to doctors and hospital emergency departments, and hospitalization for respiratory ailments.
Q6. Does ozone have an odour?
A6. Yes, ozone has a sharp, tangy smell that we usually associate with electricity, since it is most noticeable near small electric motors that produce electric arcing. Ozone is also noticeable outdoors after a thunderstorm or in the higher altitudes of mountains.
The odour threshold for ozone (the concentration level at which a person can begin to smell it) has been reported as being between 10 and 100 ppb. However, after a short exposure, ozone can deaden the sense of smell and is no longer detectable. One study found that people could smell ozone when they first entered a room containing 30 ppb, but after a few minutes they no longer noticed the smell 3.
Q7. Does ozone kill bacteria?
A7. In high concentrations, ozone can be effective in sterilizing air and water due to its powerful oxidizing action. In fact, the largest commercial use of ozone generators is for treating water in swimming pools as an alternative to chlorination. Ozone is also used in high concentrations to prevent the spoilage of stored meat.
To be effective as a germicide, the concentration of ozone must be far greater than the safety level for humans. A study by the U.S. Environmental Protection Agency indicated that ozone was not effective in killing airborne moulds and fungi, even at concentrations as high as 6,000 to 9,000 ppb -- about 100 times the recommended limit for human exposure 4.
Under the U.S. Food and Drug Regulations, a medical device which generates ozone is considered adulterated and/or misbranded if it is intended to generate ozone at less than 50 ppb per volume of air circulated through the device, and is labelled for use as a germicide or deodorizer 5.
Q8. Does ozone destroy household odours?
A8. Many people report that household odours disappear when an ozone generator is on. However, several laboratory studies have indicated that ozone did not reduce the level of chemical pollutants in air as measured by laboratory instruments 3.
A test conducted by Consumer Reports magazine 6 found that the odour of stale tobacco smoke in a room had not been effectively reduced the day after it had been treated with an ozone generator.
Because ozone can deaden the sense of smell after a short exposure, some experts believe that the reduction of odours is partly due to this masking effect, and not to the removal of odour-causing chemicals.
Q9. How effective are household air cleaners that produce ozone?
A9. Health Canada has not tested household air cleaners for effectiveness. However, even the manufacturers of air cleaners agree that ozone does not remove smoke and dust from the air; smoke and dust are removed by air circulation, filtration, or ionization. Circulation and ionization accelerate the precipitation of particles out of the air and cause them to adhere to surfaces in the room. (See Consumer Reports article 6 for more information on household air cleaners.)
Overall, there is little scientific evidence that household ozone generators are effective in cleaning the air 7.
Q10. Is the ozone level from home air cleaners hazardous?
A10. It is impossible to recommend a level of ozone which will be safe for everyone. Epidemiological studies show a steady increase in adverse health effects as the level of outdoor ozone increases, without any threshold which might indicate a safe level. However, guidelines published by the U.S. Occupational Safety and Health Administration (OSHA) recommend that ozone levels should not exceed 100 ppb averaged over an eight-hour work shift 8.
The Medical Devices Bureau has received calls from some people reporting headaches, sore throats and laryngitis when using a household air cleaner producing ozone. The symptoms reportedly ceased when the device was turned off. The American Lung Association advises that people with asthma are more sensitive than the general population to low levels of ozone 4.
Most air cleaners sold for home use claim that the ozone they produce remains below 50 ppb, but several laboratory studies have shown that these units can raise the ozone levels to more than the OSHA recommended limit of 100 ppb 9. Consumer Reports rated air cleaners that produce ozone "not acceptable" 6.
Furthermore, the ionization or static electric components of air cleaners can become dusty. This can lead to electric discharge which increases the ozone production rate. Consumers, especially those with respiratory problems, should be very careful about operating ozone generators in indoor closed areas, and should clean ionizers and electrostatic air cleaners regularly to prevent electric discharge.
Q11. Where can I get further information?
A11. For information on medical devices, you may write or send a fax to:
Medical Devices Bureau, Health Canada, Room 1605, Main Statistics Canada Bldg., Tunney's Pasture, Ottawa, Address Locator 0301H1, Ottawa, Ontario, K1A 0L2. fax: 613-954-0941.
For information on household air cleaners that are not medical devices, please contact a Product Safety Inspector in the nearest Regional Office of the Health Protection Branch:
Vancouver (604) 666-5003
Hamilton (905) 572-2845
Edmonton (403) 495-2480
Montreal (514) 646-1353
Calgary (403) 292-5613
Quebec (418) 648-4327
Saskatoon (306) 975-4028
Moncton (506) 851-6638
Winnipeg (204) 983-5490
Dartmouth (902) 426-8300
Toronto (416) 973-4705
St.John's (709) 772-4050
These Medical Devices Q's and A's were prepared by the Medical Devices Bureau, Therapeutic Products Directorate in consultation with the Environmental Health Program of Health Canada.
June, 1997
BACKGROUND NOTES AND REFERENCES
1. Health Canada, Medical Devices Regulations, Schedule VIII, "Ozone emitting devices", Office consolidation of the Medical Devices Regulations, May, 1996.
Schedule VIII reads as follows:
Ozone Emitting Devices
1. No person shall sell any device designed to generate airborne ozone to which humans may be exposed when the device is used in accordance with its directions for use or is used under such conditions as are customary or usual.
2. No person shall sell any device that generates ozone incidental to its normal operation at a level in excess of 0.05 ppm (50 parts per billion or 0.1 mg per cubic m) by volume of circulated air through the device, determined according to the test methods described in CSA standard Z223.23-M1981, "Method for the measurement of ozone in air", a standard published by the Canadian Standards Association, dated June, 1981.
The first clause is intended to prevent the sale of medical devices which make claims that exposure to ozone is beneficial to human health. Conventional medical science does not recognize any benefits from exposure to ozone. Over the past 20 years, a number of home-use ozone generators have been promoted with claims that ozone (also called "activated oxygen" or "super oxygen") increases vitality, improves well-being, or rejuvenates the skin. These are regarded as medical claims and are prohibited under clause 1 of Schedule VIII.
2. Health Canada, "Exposure guidelines for residential indoor air quality", EHD-TR-156, July, 1989.
3. Boeniger, MF. "Use of ozone generating devices to improve indoor air quality", Am. Industrial Hygiene Assoc. J., June, 1995.
4. American Lung Association, "Residential air cleaning devices: types, effectiveness and health impact", January, 1997.
5. U.S. Code of Federal Regulations, 21, Chapter 1, section 801.415, "Maximum acceptable level of ozone".
6. Anonymous, "Household air cleaners", Consumer Reports, vol. 57, no. 10, pp. 657-662, October, 1992.
7. Anonymous, "The hazards of purifying the air", Occupational Health and Safety Canada, Vol. 12, No. 2, p. 20, March/April, 1996.
8. U.S. Department of Labour, Occupational Safety and Health Administration, "Occupational health guideline for ozone," September, 1978.
9. In a study cited by Boeniger 3, two ozone generators were used in an office of 350 square ft. with 1.5 or 0.45 air exchanges per hour. The smaller unit raised the ozone level to 80 ppb at the higher air exchange rate, and 100 ppb at the lower rate. The larger unit produced levels of 300 and 500 ppb.