UV Air Cleaner Info


Everyone faces many risks, including various pollutants and toxins in their daily environments. Most people know that outdoor air pollutants such as car exhaust, city smog, factory waste, etc. are toxic. But many people do not realize how dangerous the air inside buildings can be to their health. The EPA (U.S. Environmental Protection Agency) states that the air in even the largest and most industrialized cities is less toxic than air found in typical homes. Many people do not know that indoor air pollutants can be two to five times higher than outdoor air pollution and can sometimes be 100 times higher!

It is estimated the most people spend 90% or more of their time indoors. Because of this, the quality of the indoor air we breathe every day becomes critical. Additionally, those who are indoors for the longest periods are often those who are the most susceptible to the effects of indoor air pollution-including the elderly, the young, and the chronically ill.

Various micro-organisms such as bacteria, viruses, molds, and fungi often become airborne and this is a common cause of illness or allergy. With the threat of biological warfare, the eradication of airborne pathogens becomes even more important.


There are many items in a home or office that can be sources of indoor air pollution. These include:

Building materials and furnishings:
New or damp carpeting
Cabinets or furniture made of pressed-wood products
Deteriorated asbestos-containing insulation
Combustion sources:
Tobacco products
Combustion appliances (vented or unvented):
Gas ranges and ovens
Gas water heaters
Gas clothes dryers
Wood or coal-burning stoves
Space heaters
Products for cleaning and building maintenance:
Air fresheners
Glues and adhesives
Paints and coating materials

Products for personal care or hobbies:
Hair spray
Central heating and cooling systems:
Air ducts and shafts contaminated with mold and fungi
Outdoor sources:
Outdoor air pollution (factories, etc.)
Combustion engines such as in lawn mowers or vehicles

Water vapor can affect air pollution as well. It results in wet surfaces and/or high humidity. This, in turn, promotes the growth of biological toxins such as mold, bacteria, and dust mites.

The amount of pollution a particular source gives off can vary widely, depending upon how old that source is and/or how well it has been maintained. For example, new carpeting can emit high levels of toxic gases while older carpeting has relatively few. A gas stove can give off much more carbon monoxide if it has not been properly adjusted compared to one that has been properly maintained.

Some sources of indoor air pollution release their toxins fairly continuously?­these include things like building materials, central heating and cooling systems, air fresheners, etc. Other sources release pollutants erratically-these sources are typically related to activities in the building such as smoking, cooking, the use of solvents in hobbies, redecorating, or cleaning activities; and the use of pesticides and cleaning products. High levels of these toxins can remain in the air long after the source activity has ceased.


Bacteria, viruses, molds, mildew, animal dander, cat saliva, dust mites, cockroaches and pollen are listed among the types of biological contaminants that often present in homes or offices. Sources of these pollutants are quite diverse:
Viruses are transmitted by people and animals
Pollens come from plants
Pets have saliva and dander
Bacteria are spread by people, animals, and soil/plant material
Protein from urine in mice and rats is a potent allergen and can become airborne when dry

When biological contaminants enter the central/forced air heating and cooling systems, these systems become their breeding grounds. Mold, mildew, and other pollutants are then distributed throughout the home or office.

If standing water, water-damaged materials, or wet surfaces are present, they also become breeding grounds for mold, mildew, bacteria, and insects. House dust mites are a strong biological allergen for many people and these breed in damp, warm environments.

How Biological Contaminants Affect Health

Infectious illnesses are often transmitted through the air-diseases such as colds, flu, measles, and chicken pox. Molds and mildews release toxins that can causes disease. Biological contaminants can cause health problems with symptoms such as sneezing, watery eyes, lethargy, fever, digestive problems, coughing, shortness of breath, and dizziness. Those particularly at risk for such problems are the elderly, children, and people with breathing problems, allergies, and lung diseases.

Biological agents can trigger allergic reactions such as allergic rhinitis, asthma, and hypersensitivity pneumonitis. Only after repeated exposure to a biological allergen will an allergic reaction occur. This reaction may happen on the second exposure or after many exposures over time. Because of this, even those who have noticed no reactions at all or only mild reactions might suddenly become very sensitive to particular allergens.

Humidifier fever is an illness associated with exposure to toxins from biological contaminants that breed in large building ventilation systems, as well as home heating and cooling systems and humidifiers.


According to the EPA, there are three basic ways in which the quality of the air we breathe while indoors can be improved: controlling or removing the source, improving the ventilation, or cleaning and purifying the air.

1. Source Control

An effective way to improve indoor air quality is to eliminate individual sources of pollution or to reduce their emissions. Some sources, like those that contain asbestos, can be sealed or enclosed. Other sources, like gas stoves, can be properly maintained and adjusted to decrease the amount of emissions. Source control is often a most cost-effective approach than improving ventilation because increased ventilation increases energy costs. It is difficult to control the source of indoor air pollution, however, when the issue is biological contaminants.

2. Ventilation Improvements

Increasing the amount of outdoor air that comes indoors can decrease the concentrations of indoor air pollutants. Most home heating and cooling systems, including forced air heating systems, do not mechanically bring fresh air into the home. In the absence of such a system, a homeowner's recourse is to open windows or doors, using window or attic fans, or running a window air conditioning unit with the vent open-weather permitting for all options. Localized fans such as kitchen and bathroom exhaust fans can help by removing air pollution directly from the room where the fan is located.

Office buildings can pose special challenges. In the past, most buildings had windows that opened and airing out a stuffy room was commonplace. Differences between indoor and outdoor air pressure also helped ventilation by the movement of air through leaks in the building.

Today, most newer office buildings have no operable windows, buildings are sealed tightly, and mechanical systems are the only way to exchange indoor for the relatively cleaner outdoor air. Ventilation rates, or the rate at which outdoor air is supplied to a particular building, is specified by the building code. If these mechanical ventilation systems are poorly designed, operated, or maintained, the systems themselves can add to indoor air pollution levels. Sometimes in an effort to save energy costs, ventilation systems do not bring in proper amounts of fresh outdoor air. Air supply and return vents in particular rooms can be blocked or poorly placed so that the fresher outdoor air does not reach the people in the building.

The ventilation systems themselves can be a source of pollution by spreading biological contaminants that have been breeding in cooling towers, humidifiers, dehumidifiers, air conditioners, or the ductwork. Lastly, outdoor air intake vents may be placed in areas that bring in air that has been contaminated with vehicle exhaust, dumpster fumes, boiler emissions, or air vented from restrooms. In the event of biological warfare, these intake vents may be in areas accessible to the public and thus, susceptible to pathogens being placed in the intake vents.

How the building is used can also contribute to indoor air pollution if it is not properly ventilated. Buildings that house multiple uses or businesses such as restaurants, print shops, dry cleaning stores, etc. have various emissions that may be circulated back into offices in the same building if proper precautions aren't taken.

3. Air Cleaners

Many types and sizes of air cleaners are available on the market, from relatively inexpensive table-top models to expensive and sophisticated whole-house systems. Some air cleaning systems are quite effective at particle removal, while others (particularly table-top models) are much less effective. Air cleaners are generally not designed to eliminate gaseous particles.

Many companies tout "ozone generators" as the best thing for indoor air pollution. This is not the best way to purify indoor air?­

Ozone Generators That Are Sold as Air Cleaners

( See the " Ozone Air Purifier Study " to view the EPA report on these misleading purifiers ) Click here

Ozone generators intentionally produce the gas ozone and these machines are sold as air cleaners. According to the EPA, the vendors of ozone generators often make claims that encourage people to believe that these machines are always safe and effective in controlling indoor air pollution. For nearly 100 years, health professionals have disagreed with these statements. Some manufacturers of ozone generators even claim that the federal government has approved these machines for use in occupied spaces. The EPA reports that NO federal agency has approved ozone generators for use in occupied spaces and indeed, ozone can actually cause health problems at high concentrations.

The air we breathe is comprised of mainly oxygen and nitrogen. Two atoms of oxygen comprise the basic oxygen molecule that is the oxygen we breathe (O2). A high voltage discharge (such as a thunderstorm) can create ozone by breaking apart the O2 oxygen atoms. These extremely reactive oxygen atoms recombine in groups of three and the result is ozone (O3) or trivalent oxygen. This third oxygen atom can detach from the O3 molecule and attach itself to other molecules, such as pollution, thus altering its chemical composition. This property is the basis of the claims made by the manufacturers of ozone generators.

The EPA uses the phrase "good up high-bad nearby" to describe ozone. This phrase makes the distinction between ozone in the upper atmosphere ("stratospheric ozone") which helps filter out damaging radiation from the sun, and ozone in the lower atmosphere (in the air we breathe) which is harmful to the respiratory system. This harmful ozone can be produced via an interaction of sunlight with various chemicals in the environment such as emissions by vehicles and industrial plants.

Available scientific evidence shows that ozone has little ability to remove indoor air pollutants at concentrations that do not exceed public health standards. Some manufacturers or vendors of ozone generators claims that ozone will make almost every chemical pollutant harmless by producing a chemical reaction that leaves only carbon dioxide, oxygen and water. This claim is misleading to the public.

Scientific research shows that for chemicals commonly found indoors, the reaction with ozone may take months or years.
If ozone does not readily react with a chemical, irritating by-products are often the result.
Ozone does not remove particles from the air-particles such as dust and pollen. These particles are common causes of allergies. Some ozone machines include an "ion generator" or "ionizer" in the unit. An ionizer disperses negatively charged ions which attach to particles in the air. These particles then attach to surfaces such as walls or furniture. Scientific experiments have shown that ionizers are less effective in removing pollen, fungal spores, tobacco smoke, or dust particles than other methods of air cleaning such as high efficiency particle filters or electrostatic precipitators.
Evidence shows that at concentrations that do not exceed public health standards, ozone is not effective at removing many odor-causing chemicals.
Evidence also shows that at concentrations that do not exceed public health standards, ozone does not effectively remove viruses, bacteria, mold, or other biological contaminants.
Some studies suggest that low levels of ozone may inhibit the growth of some biological pollutants and reduce their airborne concentrations. Ozone concentrations, however, would have to be 5 - 10 times higher than public health standards recommend to decontaminate the air sufficiently to prevent the regeneration of the biological contaminants once the ozone is removed.
Even high concentrations seem to have no effect on biological pollutants implanted in porous materials like ceiling tiles or duct lining.
Simply put, the ozone produced by ozone generators may inhibit the growth of biological contaminants while the ozone is present, but it is quite unlikely to completely decontaminate the air unless concentrations are high enough to become a health concern to people and pets. Contaminants embedded in porous materials may not be affected at all-even at high levels of ozone concentrations.

What's worse is that the ozone generators available produce varying and unreliable levels of ozone, even when used according to manufacturer instructions. Various factors can also influence the level of ozone produced in a room, including the size of a room, the setting of the machine, whether doors to the room are open or closed, and whether the ventilation system is turned on or off. Even if these machines are used in unoccupied spaces, when ozone is produced in high concentrations, damage can be caused to plants, rubber, electrical wire coatings, and fabrics and artwork containing susceptible dyes and pigments.


Introduction to Ultraviolet Light

The sun generates ultraviolet rays-these rays are nature's air purifier. When sunlight passes through a prism it is broken into its component colors, thus giving it the colors of a rainbow. Each color, in turn, has its own wavelengths. Ultraviolet light has four specific wavelengths that have particular applications:

UV-A is the source of suntanned skin-with its relatively longer wavelength, can penetrate the atmosphere. Applications included tanning beds and treatment of skin diseases.
UV-B is in the middle wavelength of the ultraviolet spectrum and has been used to treat skin diseases, principally.
Shortwave UV Energy or Ozone is primarily used as a sterilizer and can be generated by specially designed UV lamps.
UV-C, or shortwave ultraviolet radiation, is used to destroy bacteria and other biological contaminants in the air, in liquids, or on surfaces.

Ultraviolet Light and Microorganisms

Ultraviolet rays with this UV-C wavelength will destroy pathogens such as viruses, bacteria, mold, and mildew. This component of sunlight is the main reason that microorganisms die in outdoor air. The UV-C rays break through the outer membrane of microbes like yeast, mold, bacteria, viruses, or algae. When the radiation reaches the DNA of the microbe, it causes modifications. The DNA then transmits incorrect codes and this causes the death of the microbe.

Ultraviolet germicidal lamps provide a much more powerful and concentrated effect of ultraviolet energy than can be found naturally. Such lamps sanitize air that is passed directly in their path to destroy pathogens that come in contact with the UV rays. Musty, moldy type odors can be eradicated, along with tuberculosis, cold and flu viruses, smallpox, anthrax, and other airborne diseases. This system is particularly beneficial to those suffering from allergies-common allergens are molds, mildews, and fungi. These microbes would be destroyed, improving the health of the allergy sufferer.

Ultraviolet germicidal irradiation has been studied since the 1930's and has been used to destroy the same microbes that cause indoor air pollution. For many years, the medical industry has used UV light to sanitize rooms and equipment. The Centers for Disease Control recommend UV lamps for their germicidal effect.