The Application of Ozone Technology for Public Health and Industry
November 2005 By Laurence Franken, M.S.
In this paper we will be reviewing some of the many applications of ozone technology for use in industry and public health. When used properly and safely ozone technology can be a cheap and effective tool for eliminating many unwanted odors and indoor air pollutants. Some of the most successful applications of ozone may be in manufacturing industries such as food, beverage, pharmaceutical, healthcare, and the hospitality. In the area of public health, ozone technology may be a potential source for reducing the risk of infection both in the home and in health care facilities.
The purpose of this paper is to give an accurate representation of the technology for use in the above mentioned areas as well as dispel misconceptions about the ozone. Ozone has also been a controversial topic in the past as a result of eccentric claims about its possible uses. In order for consumers to make well informed decisions about this science we will be reviewing the advantages, as well its limitations. We will describe many of the areas where this technology can help to improve product quality in such applications as food and water processing, as well as help to make environments safer.
This paper is sponsored by EcoQuest International a leader in the development of science and technology related to indoor air and water purification systems. These systems are designed using the latest ozone and ultraviolet light technologies available. The mission of EcoQuest International is to help people live better. EcoQuest does this through the distribution of their products for use in homes, schools, and businesses.
There are numerous environmental issues facing the public health and industry here in the U.S., as well as the rest of the world. Emerging and new infectious diseases have been a growing concern since the early 1980’s (Nelson, 2004). Food safety and security has been an ongoing battle with outbreaks occurring routinely. Threat of biological or chemical attacks to our air, food, and water has also heightened since September 11, 2001.
Population growth is possibly the most important factor resulting in overcrowding and marginal sanitary conditions being associated with the increase in infectious disease (Nelson et al., 2004). An aging population of baby boomers will require nursing homes and health care facilities to take on even larger numbers of patients. Schools and daycares are also seeing more consolidation resulting in overloading of facilities. In parts of Asia overcrowding of persons with domestic birds has opened up the world to the threat of epidemic from severe acute respiratory syndrome (SARS) and from H5N1 influenza (Avian Flu) (Orent, 2005).
In the following sections applications for ozone use for possibly reducing infections in health care, hospitality industry, travel industry, clean room, medical device handling, and livestock production, will be reviewed. Also, many successful applications of ozone in food, beverage, water and wastewater treatments will be detailed. Advantages and disadvantages about ozone will be discussed along with misconceptions about the technology.
Introduction to Ozone Technology
Ozone occurs naturally in the atmosphere and serves several very important functions in our existence here of earth. A protective layer of ozone is present 6 to 30 miles above the earth’s surface at a concentration of approximately 10 ppm (parts per million). This ozone layer helps protect the earth’s surface from harmful ultraviolet radiation and prevents heat loss from the earth’s surface. Ozone is also generated during lighting, which is why the air smells so fresh after a thunderstorm.
Ozone has a tremendous ability to oxidize substances. It’s thousands of times faster than chlorine and disinfects water three to four times more effectively. Ozone seeks to oxidize everything. Human exposure to high levels of ozone will irritate lungs, eyes, and skin. Many cities post ozone levels because the sun’s UV light waves strike oxides of nitrogen from auto exhaust and factory emissions, converting them to ozone. Some researchers believe that ozone will actually help to clean up pollution, while many others feel that the negative health effects outweigh its benefits (Fink, 1994).
Ozone is a very strong oxidizer. As it oxidizes a substance ozone will literally destroy the substance’s molecule. It can oxidize organic substances such as bacteria and mildew, sterilize the air, and destroy odors and toxic fumes. Ozone has been used by industry for many years and in many different types of applications such as odor control, water purification, and as a disinfectant (Mork, 1993). Recent government approval of ozone for use with foods and food contact surfaces has opened up the door to many more exciting possibilities for this technology.
Indoor Air Quality
It is estimated that people spend approximately 90 percent of their time indoors (U.S. EPA, 1993). The health risks for most people may be greater due to exposure to bad indoor air quality than outdoors. People who are exposed to indoor pollution for the longest periods of time are often those most susceptible to the adverse effects of indoor air pollution. Sometimes indoor air problems are a result of poor building design or occupant activities. Health effects related to where individuals live or work, such as homes, apartments, offices, schools and nurseries, have become an escalating public health issue.
According to the United States Environmental Protection Agency (U.S. EPA, 1993) indoor air pollution is now considered be one of the biggest environmental health issues in this country. Indoor pollution sources that release gases or particles into the air are the primary cause of indoor air quality problems. Poor ventilation can increase indoor pollutant levels by not bringing in enough outdoor air to dilute emissions from indoor sources and by not carrying indoor air pollutants out of the home.
Sources for indoor air pollution are numerous and include such things as burning of wood and tobacco products; building materials and furnishings, carpets, and furniture made of certain pressed wood products; products for household cleaning and maintenance, personal care, or hobbies; central heating and cooling systems and humidification devices; outdoor sources such as pesticides, and outdoor air pollution; indoor animals and pests such as cats, dogs, rodents, and dust mites). All of these substances produce allergens that contribute to the incidence of diseases such as asthma (Bahnfeleth & Kowalski, 2005).
The importance of any single source depends on how much of a given pollutant it emits and how hazardous those emissions are. In some cases, factors such as how old the source is and whether it is properly maintained are significant (Tilton, 2003). Some sources, such as building materials, furnishings, and household products like air fresheners, release pollutants more or less continuously. Other sources, related to activities carried out in the home, release pollutants intermittently. These include smoking, the use of unvented or malfunctioning stoves, furnaces, or space heaters, the use of solvents in cleaners, the use of paint strippers in redecorating activities, and the use of cleaning products and pesticides in housekeeping. High pollutant concentrations can remain in the air for long periods after some of these activities.
Sick Building Syndrome
Sick-building-syndrome is any building that causes health problems such as allergies, skin rash, respiratory ailments, loss of concentration, and headaches. Most illnesses are the result of poor ventilation (Bahnfleth et al., 2005). When ducts aren’t cleaned regularly, they can release dust and fibers. Energy efficiency has limited the amount of fresh air circulated through the buildings, you still need.
Microbial contamination of indoor air represents a major public health problem and source of sick-building-syndrome. Mold for example, is a major factor in sick-building-syndrome becoming an ever increasing concern to many home owners and businesses. In addition to being unattractive to see and smell, mold also gives off spores and mycotoxins that cause irritation, allergic reactions, or disease in immune-compromised individuals (Bahnfleth et al., 2005).
Prevention of Indoor Air Pollution: Ventilation and Air Cleaners
The U.S. EPA (1990) lists three main strategies for reducing indoor air pollutants: source control, ventilation, and air cleaning. Source control is considered the most effective and eliminates the sources of pollutants or reduces their emissions. Regrettably, not all pollutant sources can be identified and practically eliminated or reduced.
Ventilation is effective because it brings outside air indoors. This is typically achieved by opening windows and doors, by turning on exhaust fans, or through the use of mechanical ventilation systems (EPA, 1993). Limitation to the use of ventilation centers around the costs for heating or cooling incoming air, and outdoor air may also contain adverse levels of contaminants (Bahnfleth et al., 2005). In the following paragraphs the most common air cleaning systems, filters, ionizers, and Ultra Violet (UV) light, will be discussed.
One of the most common filtering methods is HEPA filtration. HEPA stands for high-efficiency particulate arrestance. HEPA filters use a powerful blower to force the air through a very tight membrane to achieve high-efficiency particulate filtration. The biggest advantage of the HEPA filters is that they are very efficient in the filtering of air that passes through the filter and can filter to 0.03 micron. The drawback is that they require routine filter changes. The filter can also act as a breeding ground for bacteria, mold, and fungus. They do not remove odors, gases, pesticides, viruses, and many bacteria. They reduce airflow due to the tight pores of the filter. They are generally not used in central systems, and are sold as stand-alone units only (Fink, 1998). When air ventilation is restricted due to building design or for energy saving reasons the use of an air cleaning system is your main choice to for treating re-circulated air (Bahnfleth et al., 2005).
Carbon filters are another method of filtration, incorporating the use of carbon impregnated filter fabric or granulated carbon. These filters usually have a foam or fabric filter to hold the media. Carbon has the unique capability of acting as a physical filter trapping particulate, and on a chemical basis by reacting with some odors and some of the heavy gases. A notable advantage of the carbon filter is that it absorbs odor, absorbs some gases, and filters particulate. Some major disadvantages are the method requires frequent changes, acts as a breeding ground for microorganisms, can easily become blinded and ceases functioning.
Fiber or open-cell foam filters rely on the air passing through a matrix of foam cells or fibers of fiberglass, wire, plastic, or doth. Typically, these filters only stop medium to large particulate. The low cost is probably the main advantage to this filtration method (Fink, 1998). The disadvantages of the system are they only filter the air that passes through the filter and the particle buildup can act as a breeding ground for bacteria.
Electrostatic precipitators (Ionizers) have been used by industry for many years to clean up smoke stack emission of particulate. They operate by electrically charging a field between metal plates. The air is charged with an electrical charge similar to static electricity. The charged particulates collect and coagulate on a second set of charged plates where they build up and fall to a collection tray. Advantages include effectiveness at removing smoke from the air that passes through the filter. They do not reduce airflow as most other filters do. They can be installed in central units or in each room. The disadvantage is that they require frequent cleaning and they only filter the air that passes through the filter. The particle buildup can act as a breeding ground for bacteria.
Negative ion generators have been used by industry for years to remove particulates from the air and to neutralize the effects of excess positive ions. Negative ions are produced electrically and travel through the air until they attract airborne particulate, and coagulate the particulates until they are too heavy to drift and settle to the floor. The negative ion generators are effective at removing smoke from the air. They travel throughout the entire room and purge all the air of particulate, not just the air that passes through a filter. The down side to their use is that they drop the particulates to the ground. It is best that they be in each room, as many believe the ions cannot effectively travel through HVAC ducts.
Ultraviolet (UV) light rays have been used as a sanitizer by the medical profession for years. UV light can also sanitize air that is passed directly in its path. UV light can destroy bacteria, fungus, molds, and some gases. It does not reduce airflow. Can be installed in a central or individual room unit. The disadvantage of UV light is that is has no effect on particulate, needs direct close contact with a calculated exposure time. UV light rays must be shielded from human exposure.
Ozone Technology for Indoor Air
Ozone used for aerial treatments is typically conducted in gaseous form. In this state the ozone is colorless with a characteristic odor. Ozone consists of an oxygen molecule containing three atoms instead of two, like the oxygen we breathe. The extra atom of ozone is known as a loose radical that looks for organics to attach to and thereby oxidize. Ozone is known as a friendly oxidizer, due to the fact that it reverts back to oxygen after oxidation occurs. Ozone is an oxidizing gas that travels throughout the room and oxidizes all organics. Ozone can neutralize most odors and certain gases. Ozone destroys microorganisms and does not reduce airflow. Ozone units can be installed in central units or in each room. Ozone usage comes with safe usage limits and exposure levels must be controlled to meet government guidelines.
Ozone has been used for many years by professional cleaning and disaster restoration companies. These professionals utilize ozone to disinfect sick houses, destroy mold, mildew, fungi, or smoke from fire damage. Research has found that ozone levels of less then 9 ppm are necessary for sick buildings or profession disinfection (Khurana, 2003). These low level ozone applications have been found to be effective at reducing populations of bacteria, fungus, and viruses.
The issue of safety must always be addressed when using ozone technology for use indoors with human exposure. A study by Boeniger (1995), found that ozone air cleaners are a potential health risk if used at high levels indoors. Current ozone technology manufacturers seem well aware of this health risk and have worked to improve the science to make ozone safer for use indoors. For example, a photo-hydro-ionization (PHI) cell developed by RGF Environmental Group, Inc has been designed to not exceed the recommended Federal safety limits for ozone (0.04 ppm) in an occupied room. In the following sections on odor control and sick building
November 2005 Food Safety & Security at Kansas State University 3 http://fss.k-state.edu