OZONE
courtesy of FACTS
Stratospheric Ozone
Ozone is a gas, slightly bluish in color and with a pungent odor. It consists of three atoms of oxygen in each molecule; the oxygen we breathe contains two atoms in each molecule. Chemically, oxygen is O2, the ozone is O3. The “ozone layer” consists of ozone in the stratosphere, high above the earth at an altitude of between 7 and 28 miles. It is formed by ultraviolet light (UV) from the sun acting on oxygen molecules. The ozone layer absorbs and scatters ultraviolet light from the sun, preventing harmful amounts of ultraviolet from reaching the earth. For this reason, it is often referred to as the Ozone Shield.
Atmospheric Ozone
Ozone is also found at times in the lower atmosphere, where we breathe it. Here it is caused by ultraviolet radiation from the sun acting on smog and air pollutants on hot summer days. This situation should not be confused with the protective ozone layer in the stratosphere. Ozone at ground level is a harmful pollutant; in the stratosphere it is a protective shield.
Depletion of Stratospheric Ozone
In June of 1974, Professor Sherwood Rowland and Dr. Mario Molina of the Department of Chemistry at the University of California at Irvine first proposed the theory that certain chlorine-containing compounds could pose a threat to the ozone layer above earth. The Rowland-Molina theory said that CFC’s would ultimately cause damage to the ozone layer, which protects the earth from harmful levels of ultraviolet radiation from the sun.
Since that time, extensive research has confirmed much of the theory, and more is being learned about the way in which ozone is destroyed in the stratosphere. What follows is a summary of our current understanding.
Refrigerants that contain chlorine but not hydrogen are so stable that they do not break down in the lower atmosphere, even a hundred years or more after being released. These chemicals gradually float up to the stratosphere, where the chlorine reacts with ozone, causing it to change back to oxygen. The chlorine is not used up in the reaction; each molecule goes on to cause more and more ozone-to-oxygen reactions.
The “Ozone Hole” is a thinning in the ozone layer over Antarctica, which occurs during the Antarctic Spring season (autumn in the Northern Hemisphere). It occurs over the Antarctic continent due to the unique climate in this part of the world.
Powerful winds encircle Antarctica during its winter, isolating the continent from warmer winds that would otherwise migrate from lower latitudes on the earth’s surface. The continent is in darkness during the winter. These two effects combine to produce the coldest temperatures on earth; colder than the Arctic.
The stratosphere is normally too dry to form clouds, except at the bitterly cold temperatures reached during the Antarctic winter. At these frigid temperatures, clouds of ice and nitric acid called polar stratospheric clouds (PSCs), form in the stratosphere over the continent.
Chemical reactions take place on the surfaces of these clouds, converting chlorine from forms that do not react with ozone to other, less stable forms which readily break up in the presence of sunlight and go on to destroy ozone.
Both cold temperatures and sunlight are critical to the ozone depletion process. So it is in the spring, when the sun again rises and while the PSCs are still present, that the Antarctic ozone hole is found. As the sun warms the region in spring, the clouds dissipate.
This area is being carefully monitored for the degree to which the ozone thins out, since it has been found to lead to ozone depletion in other parts of the world, as well. Significantly reduced ozone levels were detected in 1985, and high chlorine levels were found in 1986. Since that time, instrumented aircraft flights through this layer, and ground-based instruments have indicated that the ozone depletion problem may be more serious than initially thought. We are now told that each chlorine atom in the stratosphere can destroy 100,000 ozone molecules. Air samples taken in the stratosphere have shown to contain both CFCs and chlorine monoxide, the form of chlorine that reacts with ozone as explained previously.
When ozone depletion occurs, more UV radiation penetrates to the earth’s surface. Moreover, because of the long atmospheric lifetimes of CFCs, it will take many decades for the ozone layer to return to past concentrations. Bromine-containing compounds, such as contained in halon fire extinguishers, react the same way, destroying ozone. Bromine is chemically related to chlorine.
In the years since the theory was first proposed, substantial scientific research has supported the general concern that increased concentrations in the stratosphere of chlorine, as well as bromine from halons, pose substantial risks of depletion resulting in harm to human health and the environment.
Health & Environmental Effects
Shielding the earth from much of the damaging part of the sun’s radiation, the ozone layer is a critical resource safeguarding life on this planet. Should the ozone layer be depleted, more of the sun’s damaging rays would penetrate to the earth’s surface. Each one-percent depletion would increase exposure to damaging ultraviolet radiation by 1.5 to 2 percent. EPA’s assessment of the risks from ozone depletion focused on the following areas:
· Increases in skin cancers
· Suppression of the human immune response system
· Increases in cataracts
· Damage to crops
· Damage to aquatic organisms
· Increases in ground level ozone
· Increases global warming
· Other Impacts
Ground Level Ozone—Stratospheric ozone depletion would increase the rate of formation of ground level (tropospheric) ozone, a major component of what is commonly called smog.
Degradation of Polymers—Ozone depletion would accelerate the weathering (chalking, yellowing and cracking) of plastics used in outdoor applications.
Climate Change—CFCs are also greenhouse gases; this means they have similar properties to carbon dioxide, and thus would contribute to global warming and rising sea levels.
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Monona Rossol, chemist, industrial hygienist and editor of ACTS FACTS, the monthly newsletter from Arts, Crafts and Theater Safety (ACTS), provided a wealth of information regarding ozone as utilized here “on the ground”.
Hazardous Substance Fact Sheet (New Jersey Department of Health: March 1989) offers the following:
Common Name: OZONE
CAS Number: 10028-15-6
DOT Number: UN 1693
Hazard Summary
Ozone can affect you when breathed in.
Ozone can cause irritation of the eyes, nose and throat.
Higher concentration can cause headache, upset stomach, or vomiting, pain or tightness in the chest, cough and shortness of breath.
High exposures may cause a build-up of fluid in the lungs (pulmonary edema). This can cause death. A medical emergency.
Liquefied Ozone on contact with skin or eyes may produce severe burns.
Identification
Ozone is a colorless gas with a strong odor. It is used for purifying air and drinking water, in industrial waste treatment, oils, bleaching waxes, and to make other chemicals.
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The following article by Fred Brown, appeared in the October 1992 issue of Indoor Air Review, sheds some light on the reported usefulness of ozone to reduce odors and the controversy surrounding it.
“Ozone Purifier Maker Found Guilty of Misleading Advertising, Minnesota Fines Alpine Air Products, to Pursue Case”, A manufacturer of ozone-generating air purifiers has lost a legal battle with the state of Minnesota over the safety of the devices.
The Minnesota Court of Appeals Sept. 15 ruled the company, Alpine Air Products and its president, William Converse, violated Minnesota common fraud laws by falsely representing the health benefits of its product. The appeals court also upheld a lower court decision that Alpine must refund money to purchasers who ask for it.
It further ordered Alpine Air Products and Converse to pay $70,000 in civil penalties and $104,105 in attorney’s fees.
The appeals court ruling upheld the lower court finding that Alpine Air Products had engaged in “false, deceptive and misleading claims about its products” and that it had engaged in vertical price-fixing. A request for a new trial was turned down.
A spokeswoman for the Minnesota Attorney General’s office said the ruling does not bar manufacture of the device but does prohibit deceptive advertising claims on their behalf.
Although ozone can be a powerful pollutant and is therefore closely regulated, equipment manufactured by Alpine Air Products and several other American firms’ uses miniscule amounts of ozone to fight unpleasant indoor odors.
Debate over Operation
Just how the machines work is disputed. According to one theory, ozone, which is highly reactive, breaks down the chemicals that can cause odors. Others contend the ozone works by anesthetizing the olfactory nerves.
This confusion has stirred controversy among a large number of scientists who maintain this could increase the hazard because users would lose one method of detecting danger. The gas is also blamed for various harmful effects, including reduced lung function, irritation and dryness of the eyes, nose and throat.
Company Defense
Converse told Indoor Air Review that his product was well within acceptable limits for releasing ozone. Standards set by EPA and OSHA set a limit of 0.12 parts per million. According to Converse, the equipment manufactured by Alpine generates only 0.02 parts per million, which he said is well within safety limits.
Converse said the original ruling revolved around the question of whether the product could be deemed safe if the sense of smell could not be relied on to detect a possible hazard.
To get around the problem, the company devised a manual control that can be set well within the safe limits specified. Because this is far below the level detectable by smell, Converse said the judge said this solution was not acceptable.
While conceding that his company had lost the public opinion battle over the machines, he implied the war was still not lost. He said Alpine Air Products has gone out of business but has sold the basic technology to a new company, Alpine Industries, which will continue to manufacture the devices.
A special assistant to the Attorney General, Tracy Smith, said her office would be following up the case. She agreed that the decision did not ban manufacture of the equipment. On the other hand, she said one question still to be resolved is: “Who is Alpine?” She said, “whether the ruling would also apply to the new company will depend on whether it really is a new company.”
States Are Leery
Meanwhile a sampling of state health departments around the country revealed that while the ozone generating purifiers are not yet an issue in most states, many officials remain cautious about their use.
One of those questioned, Dick Zeiler, of Indiana’s Dept. of Health, said laboratory tests done by his state at the request of one manufacturer confirmed that the machine tested did work to purify the air. But he said ozone levels, which he estimated at close to 2,000 ppm was unacceptable. He said, “There is no way we would approve that machine.”
Al Comproni, director of Hygiene for the Massachusetts Dept. of Health, said his state does not prohibit or regulate ozone-generating machines. But, he explained, “When people call in to inquire about them, we don’t recommend them. We say we would prefer to see them use something else.”
Ken Lanier of the Louisiana Dept. of Health and Hospitals said his office has had no more than three dozen calls about the ozone air purifiers over the years. He said his main objection was that the machines “don’t work very well.”
Ken McCann an environmental toxicologist for the state of Illinois, said he too is leery about recommending use of the machines. He said his department is waiting to see how other states treat the problem.
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An article from the October 1992 issue of Consumer Reports, “Ozone Generators, Two Judged Not Acceptable”.
It begins by stating that “Ozone can purify drinking water, disinfect mildewed boats, and deodorize fire ravaged buildings. But ozone is also a toxic gas, a component of smog, with no known beneficial health effects.” The review covers the Alpine 150 (Alpine Air Products), the Quantum Panda Plus Q11and the Living Air XL15 (Alpine Industries). The article concludes with the statement “Ozone generators have limited value in unoccupied spaces. But we don’t think they belong where people breathe.”
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In conclusion, we quote from the January 1993 issue of ACTS FACTS, Monona Rossol, Editor, 181 Thompson St., #23, New York, NY 10012: “Ozone is highly toxic and reactive. Even the low doses generated by the machine (0.02 parts per million) are associated with reduced lung function, irritation and dryness of the eyes, ears, nose and throat. There isn’t even any reliable evidence that ozone reduces odors. Concentrations high enough to break down odoriferous chemicals would be immediately hazardous to life. Instead, apparent reduction of odor may be related to deadening the sense of smell.”
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The following information extracted from Technical Operating Information Bulletin TOI-614, IFI Fabricare News (Nov. 1989). IFI = International Fabricare Institute, the association of professional drycleaners and launderers.
Odor Removal Service
The removal of smoke and odor problems from textiles poses a difficult task for the consumer to conquer alone. The development of ozone generators has enabled drycleaners to play an active role in aiding the consumer with deodorizing textiles while also generating another profitable service for their plants.
Ozone is a colorless gas that is the most powerful commercially available oxidizing agent. Oxidation is the process in which a substance is combined with oxygen. Oxidation causes the material with which oxygen is combined to change its molecular configuration by losing one or more of its electrons.
Oxidation occurs in the ozone generator by passing dry air through a high frequency electrical field, resulting in the formation of ozone. This electrical discharge splits an oxygen molecule into two free atoms and these atoms then combine with an oxygen molecule that has not been split to form ozone, O3. The contact between ozone and the odors embedded in the textiles causes oxidation to reoccur resulting in the elimination of the odors and the release of oxygen.
Precautions
Ozone is highly toxic even when exposure is at a low one part per million (ppm) level. Symptoms include headache, dry throat, irritation of the respiratory passages, and burning of the eyes. As proposed by OSHA, the maximum allowable exposure for an eight-hour period is 0.10 ppm. Short exposures to higher concentrations of ozone can cause throat irritations, hemorrhaging, and pulmonary edema. It has been found that symptoms of ozone exposure are acute, meaning that there are no chronic effects on healthy people because the body has the ability to repair whatever damages have been incurred. To avoid any employee contact with ozone, the generator should be run at night. Once the unit is turned off, it takes approximately 20 to 30 minutes for the ozone to convert back to oxygen, after the vent to the atmosphere has been opened. The exhaust fan should be run before anyone enters the room, after the machine is turned off.
Garments must be exposed to ozone and deodorized before dry-cleaning. Solvents such as perchloroethylene tend to lock odors into the fibers, thereby making odor elimination extremely difficult.
Since chemically ozone is an oxidizing agent, it may contribute to color loss with some dyes. Experiments have suggested that the rate of fading due to ozone depends not only on the chemical makeup of the dye, but also on the fiber in which the dye was absorbed. In general, dyed acetate fabrics that exhibit poor colorfastness may be faded by ozone. Rubber or rubber-based fabrics or products should not be exposed to ozone. Ozone’s oxidizing effect will cause rubber to decompose and disintegrate.
Here lies the answer for all of us who deal with art—ozone, an oxidizing agent, should never be used when the longevity of an item is a major consideration!
