Editor: Mercia Tapping, President, Allergy Buyers Club

PLEASE NOTE that references to prices or specials within this archive reflect prices
and market conditions at the time of newsletter publication.
Prices may have changed since publication.

In This Issue

• Health tip from Dr Grossan re smoke inhalation
• Asbestos Clean-up
• Anthrax and home protection
• IQAir Filters and Airborne Biological Warfare. Do they Help?
• Occupational Asthma Larry Martin MD
• Some responses by members about Ultra Violet in duct work
  

Shop Talk

• My recommendations for dust-mite control

Buy Allergy Control Products
from our Store!

TIPS ON SMOKE INHALATION REMEDIATION BY MURRAY GROSSAN MD

See news item at
http://abcnews.go.com/sections/living/DailyNews/wtc_healthhazards010911.html
Persons exposed to the WTC smoke and dust may suffer damage to the nasal and chest mucociliary system which can lead to infection and sinusitis. Much of this is preventable see
http://www.ent-consult.com/wtcfires.html

In a nutshell, if exposed to smoke and bad dust, you should sniff salt water in and out the nose to remove the dust and smoke particles. Drink hot tea to help restore the cilia, and breathe steam through your mouth with your tongue out. See above for detailed instructions.

Murray Grossan, M.D.
please visit
http://www.ent-consult.com
http://www.sinus-relief.com

Top

The following are excellent links for advice about asbestos dust removal for New City Residents. We are getting a number of calls around apartment clean up steps in the vicinity of the World Trade Center. Quite frankly, given the carcinogenic nature of asbestos, I would prefer that the first level of clean up to be done by a professional clean up company and you make a claim on your insurance. Please do not think that any residential hepa vacuum cleaner is up to the job - the biggest mistake we hear people making. You need a commercial level vacuum cleaner with a cloth bag.

If you are also using a heavy duty hepa air filter such as IQAir, please also be aware that you will go through pre-filters much faster than usual.

If you want some advice, our staff is happy to assist, both in their time and we will help you out financially. In the meantime, here are some excellent links about asbestos removal.

http://www.nycosh.org
http://www.nycosh.org/#anchor725602
http://www.nycosh.org/wtc-catastrophe-factsheet.html
http://www.asbestos-institute.ca
http://www.epa.gov/iaq/pubs/asbestos.html
http://www.adm.waterloo.ca/infohos/hspm/documents/asbestos/hepa_vacuum.htm
http://www.dec.state.ny.us/website/dshm/sldwaste/asbestos.htm

Top

Many of you are confused about the threat that Anthrax poses, now that Anthrax cases seem to be cropping up like mushrooms. The current type of cutaneous anthrax coming through the mail right now, is not as deadly as airborne anthrax and can be treated effectively with antibiotics. Airborne anthrax is more dangerous, all the more so as we might have no warning that a mass attack has occurred.

It is my opinion, that over and above hyper vigilance, we as individuals have only a very limited amount of preventative actions at our disposal. This is really a matter of government intervention to make sure there are enough antibiotics and vaccines on hand.

The ugly truth is that we could contract airborne or cutaneous bacterial and viral infections, any time or any place. Can your own home be one of the "safest" places? Yes, but who wants to be confined to their home all the time?

And, as Frank Hames article below makes so clear, nothing is guaranteed. I have been explaining to people all this last month, that even the best air filtration machines such as IQAir, fail to give full protection if the spores fail to reach the machine.

A useful link giving you the basics about anthrax is below.
http://www.cnn.com/2001/HEALTH/conditions/10/12/anthrax.qanda/index.html

Top

IQAIR FILTERS AND AIRBORNE BIOLOGICAL WARFARE - DO AIR FILTERS HELP?
Frank Hames, President IQAir

Editor's note: I asked Frank to put together some information for us due to the number of questions we are being asked about Bioterrorism and whether air cleaners would help.

IQAir advanced air cleaning systems have not been designed for, nor are there any claims made as to their effectiveness as a civilian bio-defense measure. IQAir believes that based upon IQAir total system efficiency for airborne particles and the option to create positive pressure areas, IQAir systems are capable in certain circumstances to reduce indoor exposure to airborne weaponized biological contaminants (AWBCs). The actual effectiveness in protecting individuals will depend on many factors outside the control of IQAir and its users. For this reason, IQAir does not make any promises or guarantees regarding the actual protection afforded by IQAir systems against AWBC exposure.

IQAir agrees with most experts that the statistical risk of exposure to AWBCs is very small. IQAir nevertheless feels responsible to comment on the possible contribution air cleaning, if properly implemented, could make in reducing exposure to AWBCs.

This article only considers air filtration in relation to indoor inhalation exposure to AWBCs. It does not address the exposure to AWBCs outside buildings, nor does it address the exposure to bio-contaminants arising out of surface contact or ingestion.

In the event, that bio-terrorists target specific buildings, these specific indoor environments pose an isolated exposure risk to occupants of that building. IQAir feels that the potential benefit of its systems will be very limited, since terrorists may be able to intentionally circumvent such a filtration measure.

If AWBCs are aerosolized outdoors (e.g. through airplanes, missiles, bombs) the greatest threat of exposure is outside buildings. In this instance, buildings may offer shelter from AWBC exposure and air filtration may add some degree of protection.

IQAir offers stand-alone, room-based filtration systems, which may reduce the potential risk of indoor exposure to AWBCs by:

* filtration of contaminated outdoor air before it enters buildings
* filtration of indoor air (recirculation)

In the case of outdoor aerosolization of AWBCs, the filtration of outdoor air before it enters the indoor environment is a priority.

In buildings with centralized forced ventilation, the filtration of the forced air stream would help to reduce the infiltration of AWBCs. IQAir does not currently offer filtration products for forced ventilation systems. HVAC contractors and HVAC filter suppliers are best positioned to give information about the filtration that these system offers and any filter upgrade possibility.

In buildings that do not have forced air ventilation, such as many residential buildings, AWBCs could enter indoors through "natural ventilation" such as open windows, ventilation openings, cracks around windows and doors, etc.. The most effective way, to reduce the infiltration of AWBCs in such naturally ventilated buildings is to create a positive air pressure area by pumping filtered outside air into the building and using ventilation openings and cracks to leak indoor air outdoors and not vice versa.

IQAir offers positive pressure air cleaning systems that consist of positive pressure accessories (IQAir Inflow W125 or IQAir Outflow W125) that if used in conjunction with an IQAir particulate air cleaning system can reduce the amount of unfiltered air leaking into a room through gaps and cracks. For more information, please refer to our "InFlow Wall Ducting Kit: InFlow W125".

Whether IQAir systems are used to reduce leakage of contaminants into buildings or to clean indoor air through recirculation, IQAir advanced air cleaning devices are capable and suitable in retaining airborne biological particles, of which AWBCs are a part. The following IQAir systems are certified by IQAir to filter airborne contamination particles which are 0.3 microns in size or larger with a total system efficiency of 99.97% or greater: IQAir HealthPro, IQAir HealthPro Plus, and IQAir Cleanroom H13.

Since most AWBCs, such as anthrax spores, are approximately 1 (one) micron in size, these IQAir devices can be expected to filter AWBCs in this size range with an efficiency of greater than 99.97%. This however, does not mean that the air in a room with an IQAir device will be 99.97% AWBC-free, as the reduction of AWBCs depends not only on the system efficiency, but also on factors which are specific to the indoor environment, such as room size, source, type and concentration of AWBCs, airflow patterns and ventilation rate.

IQAir offers for consideration that while the health risks posed by bio-terrorism are remote, the exposure to air pollution, through tobacco smoke, traffic and chemicals to millions of individuals is very real.

If anything positive comes out of the potential threat of AWBCs, it is a heightened public awareness that good air quality should not be taken for granted. And while man can go without food or water for days, he can only hold his breath for seconds.
http://www.allergybuyersclubshopping.com/iqair.html

Top

TIPS FOR DUST MITE CONTROL

I have been getting a lot of questions around dust-mite and dust control recently as I have been taking customer phone calls along with the rest of our staff. What I am reminded about is that there is no silver bullet, no one thing to do, but instead a whole long "to do" list. My advice is to go down the list one item at a time until you are symptom free.

Dust mites can live in pillows, comforters, mattresses, carpets, upholstery and clothing.
So here is a synopsis of what I tell people on the telephone.

1. First of all find out whether you have dust-mites in your environment. If you live in the South it is highly likely that you have them. In the Northeast you might like to check out ahead of time, by using a dust-mite kit [available in our store]. If you use dust mite test kits you can also check out whether your efforts have been successful or whether you need to go further down the list.
http://www.allergybuyersclubshopping.com/dustmitetestkit.html

2. Dust mites tend to flourish in humidity levels of more than 50%, so reduce the humidity levels in your house by central air conditioning and dehumidifiers. You can use a simple humidistat [like a thermometer - available at Sears and local hardware stores] to monitor the humidity levels. In my house the humidity varies from 22 to 30%. I do not have a dust mite problem.

3. Put dust mite encasings on your pillows and mattress. This is the cheapest solution. Dust mite encasings cut the mites off from their food source - your shedding skin flakes. Dust mites collect in your pillows; after a couple of years or so the dust mite droppings can account for up to 2 pounds of the pillow. The thought of burying your nose into millions of dust mites at night is quite frankly not exactly appealing!
http://www.allergybuyersclubshopping.com/dusen2.html

4. Dust mite droppings need to be vacuumed up with a hepa vacuum cleaner. Even the dead ones are allergenic. If you allow them to kick up into the air and not be vacuumed up then they will cause you a problem. So sorry- you need to get out that vacuum cleaner!
http://www.allergybuyersclubshopping.com/vacuumcleaners.html

5. Every time you walk around the room, it stirs up the settled dust mites into the air where you can inhale them. Inhaled allergens can cause the respiratory problems you are trying to avoid. Therefore,the next step in the program is to use a first class hepa air cleaner.
http://www.allergybuyersclubshopping.com/airpurifiers.html

6. Maybe the best solution of all, is to use a vapor steam cleaner to kill dust mites every 8 weeks. Dust mites have an alarming habit of coming back- the eggs lie dormant for months on end. The intense heat of a steam cleaner kills all living organisms. You can use the dry steam to kill dust mites in your mattresses, carpets, clothes, and upholstery.
http://www.allergybuyersclubshopping.com/vapor-steam-cleaners.html

7. Then finally, retest using the test kits again. They will give you a good idea of how your anti dust mite program is doing.

See our handy product comparison charts for air cleaners, vacuum cleaners and vapor steam cleaners at http://www.allergybuyersclub.com

Top

Dr. Lawrence Martin is a board-certified pulmonary specialist practicing in Cleveland. He is an examiner for the Ohio Bureau of Workers= Compensation on pulmonary-related cases, and Associate Professor of Medicine at Case Western Reserve University School of Medicine. Dr. Martin has authored several medical books and numerous papers. His web site is www.mtsinai.org/pulmonary.

Q. What is asthma?

A. Before discussing work-related asthma I will briefly define asthma in general. Asthma is a pulmonary condition characterized by episodic airflow obstruction that is at least partially reversible. Obstruction to flow of air occurs in the bronchial tubes within the lungs. In asthmatics these air passages become inflamed when affected by various triggers; the inflammation in turn leads to narrowing ("bronchoconstriction") and resultant respiratory symptoms.

Asthma symptoms typically manifest as wheezing, chest tightness, cough and shortness of breath. Wheezing is a high pitched sound generated by air going through the constricted passages. Shortness of breath is typically felt with exertion, but in severe cases can be at rest.

Symptoms are highly variable, from mild and non-limiting, to disabling and, rarely, fatal. Overall, asthma is a common condition, affecting in some fashion an estimated 5-10% of the general population (1, 2).

Q. What is the cause of asthma?

A. At a basic level the cause of asthma is unknown. Given an individual's predisposition to asthma, a variety of factors can trigger symptoms (Table 1). Perhaps the most common trigger in adults is respiratory viral infections, including the common cold. Less common, but very important, are allergens, substances that when inhaled can react with the host's antibodies to generate an "allergic" response. Allergens include various plant pollens, animal furs, excreta from house mites, proteins in shellfish, and some metals. Allergens play a major role in many cases of occupational asthma.

Irritants can also trigger an asthma attack through a non-allergic mechanism, by directly injuring cells within the lungs. Other triggers of an asthma attack include climate changes; exercise, particularly in cold weather; certain medications such as aspirin; and acid-reflux from the stomach. Although everyone is subjected to the types of triggers listed in Table 1, only the 5-10% of the population "with asthma" are prone to develop symptoms when so exposed.

TABLE 1
Some common triggers of symptoms (the "asthma attack") in patients with asthma

* Respiratory viral infections
* Allergies (e.g., to pollen, animal fur, grain dust, dust mites, shell fish, diisocyanates, etc.)
* Irritants (smoke, fumes, gases, other pollutants)
* Climate changes
* Exercise (particularly in cold air)
* Sinus infections
* Drug reactions, e.g., aspirin
* Stomach acid reflux

Q. What is work-related asthma?

A. There are two basic types of work-related asthma (3).

Work-related asthma

1. Occupational asthma
With latency period - allergic
Without latency period - irritant (RADS)

2. Work-aggravated asthma
The first type - also called "occupational asthma" is when the asthma first begins on the job, and is directly related to the job. Two types of occupational asthma are distinguished by whether symptoms appear after a latency period, i.e., a period of time (weeks to years) between the very first exposure and first development of symptoms.

* With latency period. This is "allergic" or "immunologic" asthma. With repeated exposure over time to an "allergen", such as latex in hospital gloves, the worker becomes "sensitized" to the allergen. The next exposure after sensitization might lead to symptoms diagnosed as asthma.

* Without a latency period. This is "non-allergic" or "non-immunologic" asthma, and is better known as "irritant-induced" asthma. It is also sometimes called reactive airways dysfunction syndrome, or RADS. The irritant - typically a chemical fume - inflames the airways and the worker has symptoms immediately.

In both types of "occupational asthma" symptoms can range from mild to life-threatening, and leave the worker chronically disabled. Generally, once a worker is "sensitized" he or she must no longer be exposed to the allergen, as even tiny amounts can trigger renewed symptoms.

The second type of work-related asthma is called "work-aggravated asthma". This is when pre-existing asthma (such as childhood or teenage asthma) flares up because of exposure to some allergen or irritant on the job. Distinction between true "occupational asthma" and "work-related asthma" is often important because workers= compensation agencies may handle them differently; to the individual patient, though, asthma is asthma, and overall management should be no different.

Q. How common is work-related asthma?

A. It is estimated that one out of 10 adult asthmatics have a work-related connection, i.e., asthma either caused directly by their occupation or with pre-existing asthma reactivated by the job (4).

There are approximately 200 million people in the U.S. age 18 or older (source: www.census.gov). Given a 5-10% prevalence rate of asthma, an estimated 1-2 million U.S. adults have asthma in some way related to work place exposures. (These are prevalence estimates, and do not mean 1-2 million new cases each year.)

Q. What are some allergens that can cause work-related asthma?

A. Many people mistakenly equate all asthma with "allergy", but in fact allergy is only one of the potential triggers of an asthma reaction (Table 1), including work-related asthma. However, on the job, allergy is an important cause of asthma. Over 250 substances have been identified in the workplace that can elicit an antigen-antibody response and cause occupational asthma. These allergens are typically categorized as high or low molecular weight compounds (1-3, 5), but the two groups cannot be distinguished on clinical grounds. Generally, high molecular weight compounds are mostly proteins from animals and plants; low molecular weight compounds include numerous chemicals. Examples of these compounds and the occupations at risk are given in Table 3.

TABLE 3.
Some Antigens Responsible for Work-related Asthma

Low molecular weight diisocyanates are the leading causes of occupational asthma (5); they are used in many different manufacturing processes and their fumes can sensitize the worker. Occupational asthma can also occur in "clean" environments, such as in the pharmaceutical industry, where workers may develop sensitization after repeated exposed to low molecular weight antibiotics; an example is latex allergy.

Q. How does asthma arise from latex allergy?

A. Latex allergy is an example of occupational asthma in a clean environment. Latex allergy in health care workers appears to be increasing in incidence (6-9). Latex, or natural rubber, is found in many medical products, particularly gloves. Latex allergy is also seen in patients repeatedly exposed to health care workers= gloves and other latex-containing products. Allergic reactions range from contact hives (skin reaction only) to asthma and in some extreme cases, shock (anaphylaxis). For this reason many hospitals and dental offices have switched to non-latex gloves and other products. (Note that latex is not just confined to gloves, but is a component of numerous other hospital products, including intravenous lines and ventilation bags.)

Factors predisposing to latex allergy include a history of other allergies (such as hives or hay fever) and frequent exposure to latex products. Sensitization to latex doesn't happen after a single exposure; instead, the worker becomes sensitized to the latex after repeated exposures, over time. Antibodies gradually build up until there is sufficient amount to produce an antigen (latex) - antibody reaction that produces bronchial inflammation and symptoms. Asthma from latex allergy is thought to arise from repeated inhalation of airborne latex particles that adhere to the cornstarch used to powder gloves (10-11). (Cornstarch is placed in gloves to make them easy to slip on and off.)

Q. What is RADS?

A. RADS, or reactive airways dysfunction syndrome, was first described in the 1985, is now a well-recognized form of occupational asthma. It is non-immunologic, i.e., unrelated to allergy. The exposure is obvious and the symptoms are usually immediate, although they may gradually worsen over the first 24 hours (see Table 4). The inhaled irritant (e.g., fumes from a chemical spill), causes direct irritation of the lining of the bronchial tubes, leading to asthma symptoms. Symptoms can persist long after exposure, and indeed become chronic and disabling.

TABLE 4.
Reactive Airways Dysfunction Syndrome (RADS) (12-13)

** Exposure to a high concentration of irritant gas, smoke, fume, or vapor
** Immediate onset of symptoms after single exposure to the irritant, although symptoms may not peak for several hours
** Documented absence of preceding respiratory complaints
** Symptoms (cough, wheeze and/or dyspnea) persist at least 3 months
** Presence of airflow obstruction on pulmonary function testing
** Presence of non-specific bronchial hyper-responsiveness
** Other pulmonary diseases ruled out

How do I know if I have work-related asthma?

Sometimes it's obvious, sometimes very difficult to know. While there are a variety of sophisticated tests (including blood and breathing tests) to help physicians diagnose this condition, perhaps the most important is the medical history. Medical history includes information about your medical condition before the job began and the specific relationship of your symptoms to job activities.

For example, an obvious case of occupational asthma would be a 30-year-old woman who: a) never smoked; b) never had asthma or respiratory symptoms before starting a new job; c) after working on a new job for months to years, develops wheezing, cough and shortness of breath; d) notes that her symptoms get better away from work (weekends, or vacation), and flare again back at work; d) works with a specific chemical that is known to cause occupational asthma (e.g., toluene diisocyante); e) is diagnosed with asthma by breathing tests.

A much more difficult case would be a 35-year-old man who: a) currently smokes, and has smoked a pack a day for 15 years; b) has a history of episodes of "bronchitis" before taking a new job in a factory at age 34; c) develops a respiratory infection with fever, and then notes trouble breathing; d) gets more short of breath when he returns to work after recovering from the infection. This patient may in fact have smoking-related chronic obstructive disease exacerbated by infection, and not work-related asthma. Only by testing and further history could a physician make a reasonable determination.

Q. I might have work-related asthma. What should I do?

A. There is one cardinal rule that every worker must remember: Your health comes first. If asthma occurs on the job, and the job doesn't change, the asthma won=t get better. The worker must remove himself or herself from the environment. If this is you, I recommend seeing an asthma specialist as soon as possible. Be prepared to give a detailed history of your symptoms and their relationship to the job. Ideally, this information should be written down and handed to the physician. If there is a strong suspicion based on your history, your doctor can write a note asking for a position change within the company (if possible), or that you stay off work while tests are performed. Again, the diagnosis may not be obvious, and it may take time to make a reasonable assessment.

Q. Can I get worker's compensation for work-related asthma?

A. Every state runs a worker's compensation agency, and work-related asthma is certainly compensable. The worker will have to satisfy some stringent medical criteria. Usually, an exam will be ordered with a state physician (i.e., someone other than your treating physician).

More often than not, the employer will dispute the diagnosis, and may ask for yet another exam with a physician they designate. Conflicting reports are common, making it difficult for a workers' compensation agency to decide on a case's merits. In truth, these agencies were originally set up to compensate "injured" workers, and this meant broken limbs and other external injuries. It is much more difficult to adjudicate a medical diagnosis like asthma: a) where the cause is often not obvious; b) in which symptoms can be extremely variable, and c) that is also very common in the general population. Given the potential for disagreement, it is not surprising that the decision of the compensation agency is often appealed.

If you think you have work-related asthma, by all means get it checked out, but don't expect a speedy resolution. And remember: your health comes first.

Q. Does cigarette smoking predispose to occupational asthma? If I smoke will it be more difficult to prove I have occupational asthma? Will my symptoms likely improve if I quit smoking?

A. Yes. Yes. Yes. No point in belaboring the obvious.

Q. I have asthma and am taking several medications that control my condition. Should I still avoid a dusty environment?

A. By all means, yes. The fact that you need asthma medications to control your condition is warning flag; any dusty environment could trigger your symptoms. Note that the offending work environment could be outdoors, e.g., work around diesel truck fumes or dust in an outdoor saw mill. Or, it could be indoors in a non-factory setting, such as a smoke-filled bar. Evaluate your potential job environment carefully if you have asthma.

Q. Is treatment of occupational asthma different from regular asthma?

A. Treatment of work-related asthma is no different from asthma unrelated to the job, with one important exception: advice about continued working. If a worker has developed an allergic reaction to something in the environment (i.e., is "sensitized" to it), he or she must leave that environment. The quicker they remove themselves, the better the outcome; studies have shown that continued exposure to the sensitizing agent is associated with further deterioration of lung function (14-15). Masks and other devices to minimize the exposure are of no help, and should not be relied on. Even tiny amounts of allergen can trigger a reaction if the worker is sensitized to it.
On the other hand, if the asthma was due to a one-time irritant exposure, and the irritant is removed completely, than there should be no contraindication to continued working in that environment. Sometimes, though, other pollutants in the environment may bother the worker more than before, even though the specific agent causing the asthma is removed.
Although stopping exposure generally results in clinical improvement, this is not invariable, particularly if the worker is a smoker or has co-existing sinusitis (which can also trigger asthma exacerbations). Even without these other conditions, the patient may continue to manifest asthma symptoms and require medication for months or years after leaving the job (15).

Q. I hear what you say, and I have asthma symptoms at work, but there is no way I can quit my job. What can I take for it?

A. If that is your situation, then you must work with a physician to find the best strategy. Generally, this is two-fold. First, some type of airway protection (masks, changes in ventilation at the work site, etc.) that your doctor may be able to recommend to your employer. Second, there are numerous asthma medications on the market, and finding the proper regimen is often a matter of trial and error.

If you continually function on two (out of 6) cylinders day in and day out, you could end up a "respiratory cripple" With attention to airway protection, and proper medication, your physician may be able to get you up to 4 or 5 cylinders, and still keep you on the job.

Top

From Jay Bennett
The Professor doesn't understand the real use of UV lamps in residential air conditioners. The UV lamps are mounted in the duct right next to the condensation pan. In hot humid climates, these pans are reservoirs for mold colonies. The purpose of the UV lamp is to prevent the growth of the mold, not kill the mold spores or bacteria passing through the duct. The lamp really isn't strong enough to sterilize all the air passing through the duct. A properly made UV lamp system is designed to produce as little ozone as possible. The ozone should completely recombined before the air is exhausted into the living area.

No I don't sell or profit by the sale of UV lamps. But I am thinking of getting one someday when they become a little cheaper to install.

From: DerekLafer@aol.com [mailto:DerekLafer@aol.com]
Editor's note. NQ environmental are the manufacturers are the Clarifier machine found on our site.

I would like to reply to Professor Thad Godish's assessment of the viability of UV systems in a residential air handling system. My name is Derek Laferriere, and I am the Vice President of Commercial & Medical Sales for NQ Environmental Inc.

While most of Professor Godish's statements were true, some of what he has said is misapplied or not completely stated, and his final judgement on the merits of UV are invalid. My company has been making HEPA/Ultraviolet Air Treatment Systems for high risk infection control applications (TB Isolation Rooms, Laboratories, Bronchoscopy Suites, etc..) for almost nine years. We were on the forefront of the use of UV for destroying airborne bacteria and viruses in the hospital market before the explosion of small ineffective UV systems in the commercial/residential market. In his reply, Professor Godish acknowledged the efficacy of UV for use in the hospital market. As such, it should follow that when the technology is used correctly, the same efficacy should hold true in the commercial/residential applications.

Professor Godish's assertion that there is little need for UV in HVAC systems due to the time it takes for the microorganisms to enter the system and get deactivated is valid to a point. Contaminants that are created and or dispersed "in-room" cannot effectively be removed by a central HVAC system. But this is due to the limitations of the air conditioning system, not that of UV, in that it is a difficult and very slow process for air conditioning systems to completely remove smoke, dust, odors, etc. from a room.

This is why we recommend either portable or wall-mounted units for individual rooms. In-room units that create effective air flow patterns can move or remove contaminated air, thereby preventing the spread of infectious air within a room. Our commercial/residential units (used in thousands of homes and offices), like our hospital product line (used in hundreds of facilities across the world), sends clean air to the ceiling where it can spread across the room, pushing contaminated air to the floor, out of the breathing zone, where it can be drawn back into the unit. This type of laminar-flow air flow pattern is recommended by the Center for Disease Control for infection control purposes. Central forced air systems are just incapable of creating such an air flow pattern, so I agree that the viability of a UV system in an HVAC system is limited for in-room contamination.

HOWEVER, UV in central HVAC systems can be used effectively if it is used to prevent contamination within central systems. Mold, bacteria, and virus growth inside ductwork are the primary contributors to Sick Building Syndrome. The moisture and warmth found in around air conditioning coils and within ductwork create an excellent host environment for any number of bacteria and disease, most notably Legionella. If installed next to drip pans and along A/C coils, simple UV lamps can destroy and prevent mold and other microrganism growth. It is these mold spores and bacteria that cause many people's allergic reactions and sicknesses, and which cause foul odors to come from your air supply. Therefore, small UV lamp systems can provide a valuable service inside air conditioning systems, but their goal would be limited to controlling the spread of microorganisms from the ductwork.

As such, I must wholeheartedly disagree with Professor Godish's assessment that UV lights in most air cleaning systems is a "snake oil kind of thing". They can provide a valuable service when their capabilities are understood. A major problem we have as a UV manufacturer is the misinformation prominent in the marketplace about UV. People with no UV experience have "developed" UV units that they say can peform a multitude of tasks, and this is what they preach to the consumers. I have seen hundreds of such units where the companies maintain their single UV lamps will remove bacteria, viruses, dust, odors, chemicals, particulate, ions, etc. from any air stream. These are just unrealistic expectations from people with little understanding of how UV works.

The fact remains that UV is capable of only doing so much. Airborne bacteria and viruses can be destroyed, but this requires that the unit be engineered and designed to create a high UV dosage. UV dosage is a factor of the intensity of the UV light, and the amount of time the microorganism is in contact with it. Suffice to say that a single lamp in a residential AC system will do little or nothing to destroy airborne bacteria as many manufacturers will insist, given the one (or two) lamp(s) have little intensity and the air passing by it goes upwards of 1,500 cubic feet per minute. Any interested consumer should ask their salesman what the UV dosage is of the unit they are considering. If the salesman cannot come up with a UV dosage (which is different than the intensity of the UV light), then this person does not know what they are selling.

Finally, regarding ozone production, we at NQE acknowledge the unhealthy nature of ozone, so we use non-ozone emitting UV lamps. While ozone is a natural byproduct of UV lamps, lamps do exist that prevent the ozone from being emitted from the lamp. Lamps having special quartz keep ozone within the lamp, preventing ozone leakage. Ozone emission is therefore not inherent in all UV lamps, as Professor Godish indicated; it only occurs where this is a desired result.

Most commercial UV units use ozone emitting UV lamps for the added odor reduction achieved by the ozone. However, these units, in my opinion, are quite dangerous given that ozone can be harmful and potentially lethal in high enough quantities. Given these ozone emitting lamps cannot effectively control the ozone output (it varies with the amount of air passing by them), I agree wholeheartedly with Professor Godish's assessment of ozone. But I would like to confirm that non-ozone emitting UV lamps do exist (trace amounts can be emitted, but this is significantly less that that of a computer printer), and are used widely in our hospital and commercial/residential equipment.

In all, UV systems in residential and commercial air conditioning systems do provide a worthy service if applied correctly. Smaller systems can be effective in preventing mold and bacteria growth on A/C coils and the drip pan, or in other high moisture areas. And larger systems that are engineered to create a high UV dosage can be used to effectively disinfect supply air or return air (air returning from the house or building). They are also key aspects of infection control in commercial and medical facilities, to deter the spread of sickness from room to room or floor to floor (such as in a Nursing Home). Again, these units are more than simple one or two lamp systems, as they are typically a series of UV lamps, and they need to be custom designed on a case by case basis to ensure the proper UV dosage is created.

In short, the rapid rise in UV units on the market and they manner in which they are misapplied has certainly discredited our use of UV in these areas. However, with proper education, and most importantly the correct application and expectations of this technology, UV can be an invaluable tool in creating healthy air in your home and office.

Sincerely,

Derek A. Laferriere
Vice President - Commercial & Medical Sales
NQ Environmental Inc.

Clarifier machines can be found at
http://www.allergybuyersclubshopping.com/car20airpur.html

Top

Buy Allergy Control Products from our Store

  Our Rating System
   = poor
   = fair
   = good
   = very good
   = excellent