Category: Asthma and Allergies

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Asthma and Cleaning your AC and Heating Vents for Dust

Should You Have the Air Ducts in Your Home Cleaned to Eliminate the Dust?

According to the U.S. Environmental Protection Agency (EPA), knowledge about air duct cleaning is in its early stages, so a blanket recommendation cannot be offered as to whether you should have your air ducts in your home cleaned. The U.S. Environmental Protection Agency (EPA) urges you to read this document in it entirety as it provides important information on the subject.

Duct cleaning has never been shown to actually prevent health problems. Neither do studies conclusively demonstrate that particle (e.g., dust) levels in homes increase because of dirty air ducts. This is because much of the dirt in air ducts adheres to duct surfaces and does not necessarily enter the living space. It is important to keep in mind that dirty air ducts are only one of many possible sources of particles that are present in homes. Pollutants that enter the home both from outdoors and indoor activities such as cooking, cleaning, smoking, or just moving around can cause greater exposure to contaminants than dirty air ducts. Moreover, there is no evidence that a light amount of household dust or other particulate mater in air ducts poses any risk to your health.

You should consider having the air ducts in your home cleaned if:

There is substantial visible mold growth inside hard surface (e.g., sheet metal) ducts or on other components of your heating and cooling system. There are several important points to understand concerning mold detection in heating and cooling systems:

Many sections of your heating and cooling system may not be accessible for a visible inspection, so ask the service provider to show you any mold they say exists.

You should be aware that although a substance may look like mold, a positive determination of whether it is mold or not can be made only by an expert and may require laboratory analysis for final confirmation. For about $50, some microbiology laboratories can tell you whether a sample sent to them on a clear strip of sticky household tape is mold or simply a substance that resembles it.

If you have insulated air ducts and the insulation gets wet or moldy it cannot be effectively cleaned and should be removed and replaced. If the conditions causing the mold growth in the first place are not corrected, mold growth will recur.

Ducts are infested with vermin, e.g. (rodents or insects); or
Ducts are clogged with excessive amounts of dust and debris and/or particles are actually released into the home from your supply registers.

If any of the conditions identified above exists, it usually suggests one or more underlying causes. Prior to any cleaning, retrofitting, or replacing of your ducts, the cause or causes must be corrected or else the problem will likely recur.

Some research suggests that cleaning heating and cooling system components (e.g., cooling coils, fans and heat exchangers) may improve the efficiency of your system, resulting in a longer operating life, as well as some energy and maintenance cost savings. However, little evidence exists that cleaning only the ducts will improve the efficiency of the system.

You may consider having your air ducts cleaned simply because it seems logical that air ducts will get dirty over time and should be occasionally cleaned. Provided that the cleaning is done properly, no evidence suggests that such cleaning would be detrimental. EPA does not recommend that the air ducts be cleaned routinely, but only as needed. EPA does, however, recommend that if you have a fuel burning furnace, stove or fireplace, they be inspected for proper functioning and serviced before each heating season to protect against carbon monoxide poisoning.

If you do decide to have your air ducts cleaned, take the same consumer precautions you normally would in assessing the service provider’s competence and reliability.

Air duct cleaning service providers may tell you that they need to apply chemical biocide to the inside of your ducts as a means to kill bacteria (germs) and fungi (mold) and prevent future biological growth. They may also propose the application of a “sealant” to prevent dust and dirt particles from being released into the air or to seal air leaks. You should fully understand the pros and cons of permitting application of chemical biocides or sealants. While the targeted use of chemical biocides and sealants may be appropriate under specific circumstances, research has not demonstrated their effectiveness in duct cleaning or their potential adverse health effects. No chemical biocides are currently registered by EPA for use in internally-insulated air duct systems (see Should chemical biocides be applied to the inside of air ducts?).

Whether or not you decide to have the air ducts in your home cleaned, preventing water and dirt from entering the system is the most effective way to prevent contamination (see How to Prevent Duct Contamination).

What is Air Duct Cleaning?

Most people are now aware that indoor air pollution is an issue of growing concern and increased visibility. Many companies are marketing products and services intended to improve the quality of your indoor air. You have probably seen an advertisement, received a coupon in the mail, or been approached directly by a company offering to clean your air ducts as a means of improving your home’s indoor air quality. These services typically — but not always — range in cost from $450 to $1,000 per heating and cooling system, depending on the services offered, the size of the system to be cleaned, system accessibility, climatic region, and level of contamination.

If you decide to have your heating and cooling system cleaned, it important to make sure the service provider agrees to clean all components of the system and is qualified to do so.

Duct cleaning generally refers to the cleaning of various heating and cooling system components of forced air systems, including the supply and return air ducts and registers, grilles and diffusers, heat exchangers heating and cooling coils, condensate drain pans (drip pans), fan motor and fan housing, and the air handling unit housing (See diagram).

If not properly installed, maintained, and operated, these components may become contaminated with particles of dust, pollen or other debris. If moisture is present, the potential for microbiological growth (e.g., mold) is increased and spores from such growth may be released into the home’s living space. Some of these contaminants may cause allergic reactions or other symptoms in people if they are exposed to them. If you decide to have your heating and cooling system cleaned, it is important to make sure the service provider agrees to clean all components of the system and is qualified to do so. Failure to clean a component of a contaminated system can result in re-contamination of the entire system, thus negating any potential benefits. Methods of duct cleaning vary, although standards have been established by industry associations concerned with air duct cleaning. Typically, a service provider will use specialized tools to dislodge dirt and other debris in ducts, then vacuum them out with a high-powered vacuum cleaner.

In addition, the service provider may propose applying chemical biocides, designed to kill microbiological contaminants, to the inside of the duct work and to other system components. Some service providers may also suggest applying chemical treatments (sealants or other encapsulants) to encapsulate or cover the inside surfaces of the air ducts and equipment housings because they believe it will control mold growth or prevent the release of dirt particles or fibers from ducts. These practices have yet to be fully researched and you should be fully informed before deciding to permit the use of biocides or chemical treatments in your air ducts. They should only be applied, if at all, after the system has been properly cleaned of all visible dust or debris.

Note: Use of sealants to encapsulate the inside surfaces of ducts is a different practice than sealing duct air leaks. Sealing duct air leaks can help save energy on heating and cooling bills. For more information, see EPA’s www.energystar.gov/ducts

Deciding Whether or Not to Have Your Air Ducts Cleaned
Click on the thumbnail for a larger version of the graphic.

Knowledge about the potential benefits and possible problems of air duct cleaning is limited. Since conditions in every home are different, it is impossible to generalize about whether or not air duct cleaning in your home would be beneficial.

If no one in your household suffers from allergies or unexplained symptoms or illnesses and if, after a visual inspection of the inside of the ducts, you see no indication that your air ducts are contaminated with large deposits of dust or mold (no musty odor or visible mold growth), having your air ducts cleaned is probably unnecessary. It is normal for the return registers to get dusty as dust-laden air is pulled through the grate. This does not indicate that your air ducts are contaminated with heavy deposits of dust or debris; the registers can be easily vacuumed or removed and cleaned.

On the other hand, if family members are experiencing unusual or unexplained symptoms or illnesses that you think might be related to your home environment, you should discuss the situation with your doctor. EPA has published Indoor Air Quality: An Introduction for Health Professionals and The Inside Story: A Guide to Indoor Air Quality for guidance on identifying possible indoor air quality problems and ways to prevent or fix them.

You may consider having your air ducts cleaned simply because it seems logical that air ducts will get dirty over time and should occasionally be cleaned. While the debate about the value of periodic duct cleaning continues, no evidence suggests that such cleaning would be detrimental, provided that it is done properly.

On the other hand, if a service provider fails to follow proper duct cleaning procedures, duct cleaning can cause indoor air problems. For example, an inadequate vacuum collection system can release more dust, dirt, and other contaminants than if you had left the ducts alone. A careless or inadequately trained service provider can damage your ducts or heating and cooling system, possibly increasing your heating and air conditioning costs or forcing you to undertake difficult and costly repairs or replacements.

You should consider having the air ducts in your home cleaned if:

There is substantial visible mold growth inside hard surface (e.g., sheet metal) ducts or on other components of your heating and cooling system. There are several important points to understand concerning mold detection in heating and cooling systems:

Many sections of your heating and cooling system may not be accessible for a visible inspection, so ask the service provider to show you any mold they say exists.

You should be aware that although a substance may look like mold, a positive determination of whether it is mold or not can be made only by an expert and may require laboratory analysis for final confirmation. For about $50, some microbiology laboratories can tell you whether a sample sent to them on a clear strip of sticky household tape is mold or simply a substance that resembles it.

If you have insulated air ducts and the insulation gets wet or moldy it cannot be effectively cleaned and should be removed and replaced.

If the conditions causing the mold growth in the first place are not corrected, mold growth will recur.

Ducts are infested with vermin, e.g. (rodents or insects); or

Ducts are clogged with excessive amounts of dust and debris and/or particles are actually released into the home from your supply registers.

Other Important Considerations…

Duct cleaning has never been shown to actually prevent health problems. Neither do studies conclusively demonstrate that particle (e.g., dust) levels in homes increase because of dirty air ducts or go down after cleaning. This is because much of the dirt that may accumulate inside air ducts adheres to duct surfaces and does not necessarily enter the living space. It is important to keep in mind that dirty air ducts are only one of many possible sources of particles that are present in homes. Pollutants that enter the home both from outdoors and indoor activities such as cooking, cleaning, smoking, or just moving around can cause greater exposure to contaminants than dirty air ducts. Moreover, there is no evidence that a light amount of household dust or other particulate matter in air ducts poses any risk to health.

EPA does not recommend that air ducts be cleaned except on an as-needed basis because of the continuing uncertainty about the benefits of duct cleaning under most circumstances. EPA does, however, recommend that if you have a fuel burning furnace, stove, or fireplace, they be inspected for proper functioning and serviced before each heating season to protect against carbon monoxide poisoning. Some research also suggests that cleaning dirty cooling coils, fans and heat exchangers can improve the efficiency of heating and cooling systems. However, little evidence exists to indicate that simply cleaning the duct system will increase your system’s efficiency.

If you think duct cleaning might be a good idea for your home, but you are not sure, talk to a professional. The company that services your heating and cooling system may be a good source of advice. You may also want to contact professional duct cleaning service providers and ask them about the services they provide. Remember, they are trying to sell you a service, so ask questions and insist on complete and knowledgeable answers.

Suggestions for Choosing a Duct Cleaning Service Provider

To find companies that provide duct cleaning services, check your Yellow Pages under “duct cleaning” or contact the National Air Duct Cleaners Association (NADCA) at the address and phone number in the information section located at the end of this guidance. Do not assume that all duct cleaning service providers are equally knowledgeable and responsible. Talk to at least three different service providers and get written estimates before deciding whether to have your ducts cleaned. When the service providers come to your home, ask them to show you the contamination that would justify having your ducts cleaned.
bullet

Do not hire duct cleaners who make sweeping claims about the health benefits of duct cleaning — such claims are unsubstantiated. Do not hire duct cleaners who recommend duct cleaning as a routine part of your heating and cooling system maintenance. You should also be wary of duct cleaners who claim to be certified by EPA. EPA neither establishes duct cleaning standards nor certifies, endorses, or approves duct cleaning companies.

Do not allow the use of chemical biocides or chemical treatments unless you fully understand the pros and the cons (See “Unresolved Issues of Duct Cleaning).

Check references to be sure other customers were satisfied and did not experience any problems with their heating and cooling system after cleaning.

Contact your county or city office of consumer affairs or local Better Business Bureau to determine if complaints have been lodged against any of the companies you are considering.

Interview potential service providers to ensure:

they are experienced in duct cleaning and have worked on systems like yours;
they will use procedures to protect you, your pets, and your home from contamination; and
they comply with NADCA’s air duct cleaning standards and, if your ducts are constructed of fiber glass duct board or insulated internally with fiber glass duct liner, with the North American Insulation Manufacturers Association’s (NAIMA) recommendations.

Ask the service provider whether they hold any relevant state licenses. As of 1996, the following states require air duct cleaners to hold special licenses: Arizona, Arkansas, California, Florida, Georgia, Michigan and Texas. Other states may require them as well.

If the service provider charges by the hour, request an estimate of the number of hours or days the job will take, and find out whether there will be interruptions in the work. Make sure the duct cleaner you choose will provide a written agreement outlining the total cost and scope of the job before work begins.

What to Expect From an Air Duct Cleaning Service Provider

If you choose to have your ducts cleaned, the service provider should:
Open access ports or doors to allow the entire system to be cleaned and inspected.

Inspect the system before cleaning to be sure that there are no asbestos-containing materials (e.g., insulation, register boots, etc.) in the heating and cooling system. Asbestos-containing materials require specialized procedures and should not be disturbed or removed except by specially trained and equipped contractors.

Use vacuum equipment that exhausts particles outside of the home or use only high-efficiency particle air (HEPA) vacuuming equipment if the vacuum exhausts inside the home.

Protect carpet and household furnishings during cleaning.

Use well-controlled brushing of duct surfaces in conjunction with contact vacuum cleaning to dislodge dust and other particles.

Use only soft-bristled brushes for fiberglass duct board and sheet metal ducts internally lined with fiberglass. (Although flex duct can also be cleaned using soft-bristled brushes, it can be more economical to simply replace accessible flex duct.)

Take care to protect the duct work, including sealing and re-insulating any access holes the service provider may have made or used so they are airtight.

Follow NADCA’s standards for air duct cleaning and NAIMA’s recommended practice for ducts containing fiber glass lining or constructed of fiber glass duct board.

How to Determine if the Duct Cleaner Did A Thorough Job

A thorough visual inspection is the best way to verify the cleanliness of your heating and cooling system. Some service providers use remote photography to document conditions inside ducts. All portions of the system should be visibly clean; you should not be able to detect any debris with the naked eye. Show the Post-Cleaning Consumer Checklist to the service provider before the work begins. After completing the job, ask the service provider to show you each component of your system to verify that the job was performed satisfactorily.

If you answer “No” to any of the questions on the checklist, this may indicate a problem with the job. Ask your service provider to correct any deficiencies until you can answer “yes” to all the questions on the checklist.

Post Cleaning Consumer Checklist Yes No

General Did the service provider obtain access to and clean the entire heating and cooling system, including ductwork and all components (drain pans, humidifiers, coils, and fans)?
Has the service provider adequately demonstrated that duct work and plenums are clean? (Plenum is a space in which supply or return air is mixed or moves; can be duct, joist space, attic and crawl spaces, or wall cavity.)
Heating Is the heat exchanger surface visibly clean?
Cooling
Components Are both sides of the cooling coil visibly clean?
If you point a flashlight into the cooling coil, does light shine through the other side? It should if the coil is clean.
Are the coil fins straight and evenly spaced (as opposed to being bent over and smashed together)?
Is the coil drain pan completely clean and draining properly?
Blower Are the blower blades clean and free of oil and debris?
Is the blower compartment free of visible dust or debris?
Plenums

Is the return air plenum free of visible dust or debris?
Do filters fit properly and are they the proper efficiency as recommended by HVAC system manufacturer?
Is the supply air plenum (directly downstream of the air handling unit) free of moisture stains and contaminants?
Metal Ducts Are interior ductwork surfaces free of visible debris? (Select several sites at random in both the return and supply sides of the system.)
Fiber Glass Is all fiber glass material in good condition (i.e., free of tears and abrasions; well adhered to underlying materials)?
Access
Doors Are newly installed access doors in sheet metal ducts attached with more than just duct tape (e.g., screws, rivets, mastic, etc.)?
With the system running, is air leakage through access doors or
covers very slight or non-existent?
Air Vents Have all registers, grilles, and diffusers been firmly reattached to the walls, floors, and/or ceilings?
Are the registers, grilles, and diffusers visibly clean?
System
Operation Does the system function properly in both the heating and cooling modes after cleaning?

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How to Prevent Duct Contamination

Whether or not you decide to have the air ducts in your home cleaned, committing to a good preventive maintenance program is essential to minimize duct contamination.

To prevent dirt from entering the system:
bullet Use the highest efficiency air filter recommended by the manufacturer of your heating and cooling system.

Change filters regularly.

If your filters become clogged, change them more frequently.

Be sure you do not have any missing filters and that air cannot bypass filters through gaps around the filter holder.

When having your heating and cooling system maintained or checked for other reasons, be sure to ask the service provider to clean cooling coils and drain pans.

During construction or renovation work that produces dust in your home, seal off supply and return registers and do not operate the heating and cooling system until after cleaning up the dust.

Remove dust and vacuum your home regularly. (Use a high efficiency vacuum (HEPA) cleaner or the highest efficiency filter bags your vacuum cleaner can take. Vacuuming can increase the amount of dust in the air during and after vacuuming as well as in your ducts).

If your heating system includes in-duct humidification equipment, be sure to operate and maintain the humidifier strictly as recommended by the manufacturer.

Whether of not you decide to have the air ducts in your home cleaned, committing to a good preventive maintenance program is essential to minimize duct contamination.

To prevent ducts from becoming wet:

Moisture should not be present in ducts. Controlling moisture is the most effective way to prevent biological growth in air ducts.

Moisture can enter the duct system through leaks or if the system has been improperly installed or serviced. Research suggests that condensation (which occurs when a surface temperature is lower than the dew point temperature of the surrounding air) on or near cooling coils of air conditioning units is a major factor in moisture contamination of the system. The presence of condensation or high relative humidity is an important indicator of the potential for mold growth on any type of duct. Controlling moisture can often be difficult, but here are some steps you can take:

Promptly and properly repair any leaks or water damage.

Pay particular attention to cooling coils, which are designed to remove water from the air and can be a major source of moisture contamination of the system that can lead to mold growth. Make sure the condensate pan drains properly. The presence of substantial standing water and/or debris indicates a problem requiring immediate attention. Check any insulation near cooling coils for wet spots.

Make sure ducts are properly sealed and insulated in all non-air-conditioned spaces (e.g., attics and crawl spaces). This will help to prevent moisture due to condensation from entering the system and is important to make the system work as intended. To prevent water condensation, the heating and cooling system must be properly insulated.

If you are replacing your air conditioning system, make sure that the unit is the proper size for your needs and that all ducts are sealed at the joints. A unit that is too big will cycle on and off frequently, resulting in poor moisture removal, particularly in areas with high humidity. Also make sure that your new system is designed to manage condensation effectively.

Unresolved Issues of Duct Cleaning

Does duct cleaning prevent health problems?

The bottom line is: no one knows. There are examples of ducts that have become badly contaminated with a variety of materials that may pose risks to your health. The duct system can serve as a means to distribute these contaminants throughout a home. In these cases, duct cleaning may make sense. However, a light amount of household dust in your air ducts is normal. Duct cleaning is not considered to be a necessary part of yearly maintenance of your heating and cooling system, which consists of regular cleaning of drain pans and heating and cooling coils, regular filter changes and yearly inspections of heating equipment. Research continues in an effort to evaluate the potential benefits of air duct cleaning.

In the meantime…

Educate yourself about duct cleaning by contacting some or all of the sources of information listed at the end of this publication and asking questions of potential service providers.

Are duct materials other than bare sheet metal ducts more likely to be contaminated with mold and other biological contaminants?

You may be familiar with air ducts that are constructed of sheet metal. However, many modern residential air duct systems are constructed of fiber glass duct board or sheet metal ducts that are lined on the inside with fiber glass duct liner. Since the early 1970’s, a significant increase in the use of flexible duct, which generally is internally lined with plastic or some other type of material, has occurred. The use of insulated duct material has increased due to improved temperature control, energy conservation, and reduced condensation. Internal insulation provides better acoustical (noise) control. Flexible duct is very low cost. These products are engineered specifically for use in ducts or as ducts themselves, and are tested in accordance with standards established by Underwriters Laboratories (UL), the American Society for Testing and Materials (ASTM), and the National Fire Protection Association (NFPA). Many insulated duct systems have operated for years without supporting significant mold growth. Keeping them reasonably clean and dry is generally adequate. However, there is substantial debate about whether porous insulation materials (e.g., fiber glass) are more prone to microbial contamination than bare sheet metal ducts. If enough dirt and moisture are permitted to enter the duct system, there may be no significant difference in the rate or extent of microbial growth in internally lined or bare sheet metal ducts. However, treatment of mold contamination on bare sheet metal is much easier. Cleaning and treatment with an EPA-registered biocide are possible. Once fiberglass duct liner is contaminated with mold, cleaning is not sufficient to prevent re-growth and there are no EPA-registered biocides for the treatment of porous duct materials. EPA, NADCA, and NAIMA all recommend the replacement of wet or moldy fiber glass duct material.

In the meantime…

Experts do agree that moisture should not be present in ducts and if moisture and dirt are present, the potential exists for biological contaminants to grow and be distributed throughout the home. Controlling moisture is the most effective way to prevent biological growth in all types of air ducts.
bullet Correct any water leaks or standing water.

Remove standing water under cooling coils of air handling units by making sure that drain pans slope toward the drain.

If humidifiers are used, they must be properly maintained.

Air handling units should be constructed so that maintenance personnel have easy, direct access to heat exchange components and drain pans for proper cleaning and maintenance.

Fiber glass, or any other insulation material that is wet or visibly moldy (or if an unacceptable odor is present) should be removed and replaced by a qualified heating and cooling system contractor.

Steam cleaning and other methods involving moisture should not be used on any kind of duct work.

Should chemical biocides be applied to the inside of air ducts?

No products are currently registered by EPA as biocides for use on fiberglass duct board or fiberglass lined ducts so it is important to determine if sections of your system contain these materials before permitting the application of any biocide.

Air duct cleaning service providers may tell you that they need to apply a chemical biocide to the inside of your ducts to kill bacteria (germs), and fungi (mold) and prevent future biological growth. Some duct cleaning service providers may propose to introduce ozone to kill biological contaminants. Ozone is a highly reactive gas that is regulated in the outside air as a lung irritant. However, there remains considerable controversy over the necessity and wisdom of introducing chemical biocides or ozone into the duct work.

Among the possible problems with biocide and ozone application in air ducts:

Little research has been conducted to demonstrate the effectiveness of most biocides and ozone when used inside ducts. Simply spraying or otherwise introducing these materials into the operating duct system may cause much of the material to be transported through the system and released into other areas of your home.

Some people may react negatively to the biocide or ozone, causing adverse health reactions.

Chemical biocides are regulated by EPA under Federal pesticide law. A product must be registered by EPA for a specific use before it can be legally used for that purpose. The specific use(s) must appear on the pesticide (e.g., biocide) label, along with other important information. It is a violation of federal law to use a pesticide product in any manner inconsistent with the label directions.

A small number of products are currently registered by EPA specifically for use on the inside of bare sheet metal air ducts. A number of products are also registered for use as sanitizers on hard surfaces, which could include the interior of bare sheet metal ducts. While many such products may be used legally inside of unlined ducts if all label directions are followed, some of the directions on the label may be inappropriate for use in ducts. For example, if the directions indicate “rinse with water”, the added moisture could stimulate mold growth.

All of the products discussed above are registered solely for the purpose of sanitizing the smooth surfaces of unlined (bare) sheet metal ducts. No products are currently registered as biocides for use on fiber glass duct board or fiber glass lined ducts, so it is important to determine if sections of your system contain these materials before permitting the application of any biocide.

In the meantime…

Before allowing a service provider to use a chemical biocide in your duct work, the service provider should:

Demonstrate visible evidence of microbial growth in your duct work. Some service providers may attempt to convince you that your air ducts are contaminated by demonstrating that the microorganisms found in your home grow on a settling plate (i.e., petri dish). This is inappropriate. Some microorganisms are always present in the air, and some growth on a settling plate is normal. As noted earlier, only an expert can positively identify a substance as biological growth and lab analysis may be required for final confirmation. Other testing methods are not reliable.

Explain why biological growth cannot be removed by physical means, such as brushing, and further growth prevented by controlling moisture.

If you decide to permit the use of a biocide, the service provider should:
Show you the biocide label, which will describe its range of approved uses.

Apply the biocide only to un-insulated areas of the duct system after proper cleaning, if necessary to reduce the chances for re-growth of mold.

Always use the product strictly according to its label instructions.

While some low toxicity products may be legally applied while occupants of the home are present, you may wish to consider leaving the premises while the biocide is being applied as an added precaution.

Do sealants prevent the release of dust and dirt particles into the air?

Manufacturers of products marketed to coat and encapsulate duct surfaces claim that these sealants prevent dust and dirt particles inside air ducts from being released into the air. As with biocides, a sealant is often applied by spraying it into the operating duct system. Laboratory tests indicate that materials introduced in this manner tend not to completely coat the duct surface. Application of sealants may also affect the acoustical (noise) and fire retarding characteristics of fiber glass lined or constructed ducts and may invalidate the manufacturer’s warranty.

Questions about the safety, effectiveness and overall desirability of sealants remain. For example, little is known about the potential toxicity of these products under typical use conditions or in the event they catch fire.

In addition, sealants have yet to be evaluated for their resistance to deterioration over time which could add particles to the duct air.

In the meantime…

Most organizations concerned with duct cleaning, including EPA, NADCA, NAIMA, and the Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA) do not currently recommend the routine use of sealants to encapsulate contaminants in any type of duct. Instances when the use of sealants to encapsulate the duct surfaces may be appropriate include the repair of damaged fiber glass insulation or when combating fire damage within ducts. Sealants should never be used on wet duct liner, to cover actively growing mold, or to cover debris in the ducts, and should only be applied after cleaning according to NADCA or other appropriate guidelines or standards.

To Learn More About Indoor Air Quality

U.S. Environmental Protection Agency
Office of Radiation and Indoor Air
Indoor Environments Division (6609J) www.epa.gov/iaq
1200 Pennsylvania Avenue, N.W.
Washington, DC 20460

The following useful EPA publications are available on this web site, some can be order from NSCEP. (see also: www.epa.gov/iaq/pubs/)

The Inside Story: A Guide to Indoor Air Quality
Indoor Air Pollution: An Introduction for Health Professionals
Residential Air Cleaners: A Summary of Available Information
Ozone Generators That are Sold as Air Cleaners

To Learn More About Air Duct Cleaning

National Air Duct Cleaners Association (NADCA)

1518 K Street, NW Suite 503
Washington, DC 20005
Phone: (202) 737-2926
E-mail: info@nadca.com
Website: www.nadca.com exiting EPA

Find a NADCA duct cleaner near you exiting EPA

North American Insulation Manufacturers Association (NAIMA)

44 Canal Center Plaza, Suite 310, Alexandria, VA 22314
Phone: (703) 684-0084
E-mail: www.naima.org/ exiting EPA
Website: NAIMA Member Company Listing www.naima.org/pages/about/members/members.html exiting EPA

“Cleaning Fibrous Glass Insulated Air Duct Systems; Recommended Practice”, see www.naima.org/pages/resources/library/order/AH122.HTML exiting EPA NAIMA Pub. No. AH122, 40 pages (Cost is $7.50 for a printed version, no free copies available.)

Other Useful Resources

For a free list of state and local consumer protection agencies and Better Business Bureaus:

The Federal Citizen Information Center (a service of the U.S. General Services Administration)
Consumer Action Website – www.consumeraction.gov/ exiting EPA

Order a copy of the free Consumer Action Handbook online at www.consumeraction.gov/caw_orderhandbook.shtml exiting EPA

For more information on biocides:

Antimicrobial Information Hotline
Phone: (703) 308-0127 / Fax: (703) 308-6467
Monday-Friday 8:00 AM – 5:00 PM EST
E-mail: Info_Antimicrobial@epa.gov
Website: www.epa.gov/oppad001/

The Antimicrobials Information Hotline provides answers to questions concerning current antimicrobial issues (disinfectants, fungicides, others) regulated by the pesticide law, rules and regulations. These cover interpretation laws, rules, and regulations, and registration and re-registration of antimicrobial chemicals and products. The Hotline also provide information health & safety issues on registered antimicrobial products, product label and the proper and safe use of these antimicrobial products.

Consumer Checklist
Learn as much as possible about air duct cleaning before you decide to have your ducts cleaned by reading this guidance and contacting the sources of information provided.
Consider other possible sources of indoor air pollution first if you suspect an indoor air quality problem exists in your home.
Have your air ducts cleaned if they are visibly contaminated with substantial mold growth, pests or vermin, or are clogged with substantial deposits of dust or debris.
Ask the service provider to show you any mold or other biological contamination they say exists. Get laboratory confirmation of mold growth or decide to rely on your own judgment and common sense in evaluating apparent mold growth.
Get estimates from at least three service providers.
Check references.
Ask the service provider whether he/she holds any relevant state licenses. As of 1996, the following states require air duct cleaners to hold special licenses: Arizona, Arkansas, California, Florida, Georgia, Michigan and Texas. Other states may also require licenses.
Insist that the service provider give you knowledgeable and complete answers to your questions.
Find out whether your ducts are made of sheet metal, flex duct, or constructed of fiber glass duct board or lined with fiber glass since the methods of cleaning vary depending on duct type. Remember, a combination of these elements may be present.
Permit the application of biocides in your ducts only if necessary to control mold growth and only after assuring yourself that the product will be applied strictly according to label directions. As a precaution, you and your pets should leave the premises during application.
Do not permit the use of sealants except under unusual circumstances where other alternatives are not feasible.
Make sure the service provider follows the National Air Duct Cleaning Association’s (NADCA) standards and, if the ducts are constructed of flex duct, duct board, or lined with fiber glass, the guidelines of the North American Insulation Manufacturers Association (NAIMA)
Commit to a preventive maintenance program of yearly inspections of your heating and cooling system, regular filter changes, and steps to prevent moisture contamination.

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Asthma Researchers Explore New Pharma Treatment Options

A New Asthma Treatment Option Drug called Lebrikizumab Shows Results Needs Further Review Says Asthma Specialist

News reports reflect that For asthma patients who continue to suffer from symptoms even after taking their inhaled steroids, a new drug called lebrikizumab may be a treatment option, and a simple blood test can determine the effectiveness of the drug, according to a consortium of researchers including a Baylor College of Medicine asthma expert in a report that appears in The New England Journal of Medicine

Dr. Nick Hanania, associate professor of medicine and director the BCM Asthma Clinical Research Center and colleagues studied whether lebrikizumab, an antibody to interleukin-13, a protein that plays a major role in the inflammation in the airways of asthmatics, would block the effects of the protein and have an effect on lung function or flare ups in asthmatics.

The phase II clinical trial looked at 219 adults with asthma who were already taking inhaled steroids and continued to suffer from asthma symptoms. After 12 weeks, those who received the once-a-month injection of lebrikizumab had better lung function as measured by a test called forced expiratory volume than those who received a placebo. However, there were no significant effects of this drug on asthma flare ups over the six months of the study.

Researchers also found that patients in the study who had a higher blood level of a biomarker periostin, a protein that reflects high interleukin-13 activity and causes a type of inflammation in asthma patients called eosinophilic inflammation, responded better to the drug than those who had lower levels of this biomarker. These findings suggest that a simple blood test can determine which asthma patients may have a positive response to the study medication.

“This information will be very helpful in the future in better defining the role of periostin in asthma and in differentiating the phenotypes, or the characteristics, of asthma,” said Hanania. “We know that not all asthmatics are the same as there are different types of airway inflammation in this disease, and we have never had a simple test that could help us identify who would and wouldn’t respond to agents like this new drug until now.”

Hanania also notes that the safety of the drug was promising compared to the placebo.

“This is a step forward in treating asthma patients,” said Hanania. “These findings could help the well being and quality of life for those on inhaled steroids who continue to suffer from asthma symptoms. Such symptoms can cause increased hospitalizations and emergency room visits, which result in a high cost for patients and the health care system.”

Lebrikizumab will need to be studied in a larger number of patients before it can be reviewed and approved by FDA and become available to patients.

Others who took part in this study include Dr. Jonathan Corren of Allergy Medical Clinic and Genentech; Dr. Robert F. Lemanske, Jr. of the University of Wisconsin School of Medicine and Public Health; Dr. Phillip E. Korenblat of the Clinical Research Center in St. Louis.Dr. Merdad V. Parsey of 3-V Biosciences; and Drs. Joseph R. Arron, Jeffrey M. Harris, Heleen Scheerens, Lawren C. Wu, Zheng Su, Sofia Mosesova, Mark D. Eisner, Sean P. Bohen and John G. Matthews of Genentech.

Funding for this study came from Genentech, a member of Roche group.

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Food Allergy Challenges

Food Allergy Challenges, Asthma and U.S. National Guidelines

In this PBS audio podcast on Food Allergy, the invited experts discuss Food Allergy Challenges and new national U.S. Guidelines for physicians and patients.

Topics covered:

* Food Allergies and New U.S. National Guidelines
* Food Intolerance vs. Food Allergy
* Benefits, Pitfalls and Challenges of Comprehensive Food Panel and Test
* Benefits and challenges of logging your diet
* Benefits of advocating for yourself
* Improvements in research and diagnostic testing

Ten to 12 million people in the U.S. suffer from a food allergy, according to the National Institute of Allergy and Infectious Diseases — and the number is growing. Diagnosis and treatment can be difficult. The NIAID hopes the new guidelines will help physicians identify and manage food allergies.

NEAL CONAN, host:

This is TALK OF THE NATION. Im Neal Conan in Washington.

Food allergies are all too common. As many as 12 million Americans may have one or more, and they can be dangerous, sometimes even fatal. But it can be hard to figure out who’s allergic and who isn’t, and the severity of reactions can vary greatly. A whiff of peanuts can make one person break out in hives or send another into anaphylactic shock.

Many restaurants and schools don’t label meals that contain the foods that can trigger an allergic reaction or at least not correctly sometimes, and the number of cases appears to be on the rise.

The National Institute of Allergy and Infectious Diseases released new guidelines in December to help health care professionals who treat patients with food allergies. If that’s you or your child, how did you and your doctor figure it out? Tell us your story. 800-989-8255. Email us, talk@npr.org. You can join the conversation on our website. That’s at npr.org. Click on TALK OF THE NATION.

Later in the program, crowd disasters. What really triggers a dangerous crush? And new ideas on prevention. But first, food allergies, and we begin with Matthew Fenton, chief of the Asthma, Allergy and Inflammation Branch at the Division of Allergy, Immunology and Transplantation -almost made it through – at the National Institute of Allergy and Infectious Diseases. That’s not quite a mouthful. He joins us here in Studio 3A. Thanks very much for being with us.

Dr. MATTHEW FENTON (Chief, Asthma, Allergy and Inflammation Branch, Division of Allergy, Immunology and Transplantation, National Institute of Allergy and Infectious Diseases): Thank you. It’s a pleasure to be here.

CONAN: And why the necessity for new guidelines?

Dr. FENTON: Well, we were actually approached by a patient advocacy group and a professional medical society back in 2007 with the idea that there needed to be updated food allergy clinical guidelines that would speak to the entire clinical community and not simply be guidelines written by allergists for allergists, which has been the case sometimes in the past.

And so we took on the challenge of creating guidelines that could be broadly useful across the clinical spectrum, ranging from the specialist to the general family practice doctor.

CONAN: Does that suggest that, at least in the past, treatment have been very different?

Dr. FENTON: Well, diagnosis and management of food allergy has been very different. One of the startling facts is that there is not even a common definition for food allergy that is used by physicians in different types of practice.

One of the things we did when we started the project of creating guidelines was to look at the definitions that were out there, and they vary quite a bit. So we had our work cut out for us.

CONAN: In fact, it’s sometimes hard to distinguish, and certainly from a layman’s point of view, between an allergy and an intolerance.

Dr. FENTON: Absolutely. The symptoms can be very similar, and it’s certainly quite plausible that a diagnosis of food allergy can be made, only to later find out it’s a food intolerance.

And interestingly, for patients who self-report that they have an allergy to their doctor, 50 to 90 percent of the time, they’re actually incorrect, and they have a food intolerance.

CONAN: And what’s the difference in terms of treatment?

Dr. FENTON: Well, there – for food allergies, which are a disease that’s based on a defect in the immune response to food, there is no treatment. We can only advise patients and their families to manage the diet and be very careful to avoid consumption of the food or to manage symptoms, if they’re mild, with antihistamines, or in the case of severe reactions, you may have to use epinephrine.

In the case of food intolerance, you certainly want to avoid the food, as well, but in cases such as lactose intolerance, you know exactly what you need to avoid in milk products, but also there are pills available to provide the missing lactase enzyme, and you can actually then go on to consume milk products.

CONAN: And allergies can be, I think devilish is probably as good a word as any, figuring out what it is you’re allergic to.

Dr. FENTON: Well, that’s a very important point. And one of the things I want to stress at the beginning is that there’s a difference between allergic sensitization and allergic disease, that the immune system may recognize a number of different allergens, but you may only have clinical disease arising from one of those allergens.

CONAN: So give me a for instance there.

Dr. FENTON: Well, for instance, let’s take food allergies, since it’s the topic of the day. You may have an immune response against a number of different foods. A child may be allergic to milk and egg and peanut. But which one is actually causing the symptoms? And finding out which is the culprit is a large part of the challenge the physician faces. But only the one that you have clinical symptoms from is the one you have to avoid in your diet.

CONAN: Dr. Fenton, stay with us. We’re going to turn to somebody who has to deal with some of these problems in his practice. Dr. Hemant Sharma is director of the Food Allergy Program at Children’s National Medical Center here in Washington, D.C., also with us here in Studio 3A. And you deal with these kinds of questions all the time.

Dr. HEMANT SHARMA (Director, Food Allergy Program, Children’s National Medical Center): Absolutely. I was just dealing with them this morning, in fact, with several of our patients that came to see us.

And, you know, the concerns that families have when they come to see us as a specialist is, number one, making the diagnosis. Oftentimes, they come to us after having had various tests done and without much clarity as to whether their child really has a food allergy, and if they do, which foods are they really allergic to.

CONAN: And we’re talking children here, but are most allergies diagnosed in children?

Dr. SHARMA: Well, of the about 12 million people in the U.S. who have a food allergy, three million of them are estimated to be children. So there are a number of adults who have food allergy, some of whom had food allergy as kids and never outgrew them. And some adults develop food allergies later in life.

CONAN: So is that a separate category?

Dr. SHARMA: Not necessarily. They all work through the same mechanisms, and, you know, going back to what Dr. Fenton said, food allergies, by definition, involve the immune system.

And so most of the time, when it comes to a food allergy, that will happen early in childhood. However, for example with fish and shellfish, that allergy can develop anytime, later in adulthood.

CONAN: And is the testing still, well, we’ll give you a little of this and see what happens?

Dr. SHARMA: Not exactly, and I think that’s one of the strengths of the food allergy guidelines that we’re discussing is that they’re giving us a framework for the interpretation of these tests.

There are a number of tests that allergist, immunologists can do when a child or an adult comes to them with food allergy concerns. A skin test can be done. A blood test can be done. And sometimes those tests are not always accurate. There can be false positives, as we were discussing before.

So the job that we have in front of us is to take not only the test results but more importantly the history of what happened, the history of when your child or when you ate this food, what symptoms occurred, how soon did they occur. And we put all that together to help make a diagnosis.

CONAN: And especially in the case of children, of course, the parents are sometimes distraught because these reactions can sometimes be very scary.

Dr. SHARMA: Absolutely. I mean, food allergy for a parent is a very frightening thing to go through, particularly in young children. They have life-threatening reactions. These are not the kinds of allergy symptoms that we think of with hay fever, for example, a runny nose or itchy eyes. These symptoms can be a drop in blood pressure, a dangerous tightening or swelling involving the through. And they can be potentially fatal. And so for parents, this is a very, very scary prospect.

CONAN: As a practitioner, do you look at these new guidelines and say: Does this make sense to you? And does it clarify – did these definitions clarify procedures throughout the profession?

Dr. SHARMA: Absolutely. As an allergist-immunologist who treats people with food allergies, these guidelines have been incredibly helpful, number one in terms of getting us on the same page.

I think as Dr. Fenton was alluding to, there’s a wide variety of clinical practice when it comes to food allergy, and as practitioners, we all needed a set of common guidelines to help us to decide what we should do when a patient comes to us with a potential food allergy.

And then furthermore, for patients themselves, it gives us a set of guidelines to guide them in better understanding and managing their food allergies.

CONAN: Let’s get a caller in on the conversation, 800-989-8255. Email us, talk@npr.org. If you have a food allergy, or your child does, tell us how you and your doctor figured that out. Megan(ph) joins us on the line, calling from Mountain View in California.

MEGAN (Caller): Hi.

CONAN: Hi, Mega, you’re on the air. Go ahead, please.

MEGAN: So, I’ve been working actually from the opposite perspective of not necessarily thinking I have food allergies but having a lot of symptoms, and over the last year working with a naturopath until we ended up sending my blood in to get a comprehensive food panel. And they sent back a list of about 30 different foods, which I’m allergic to.

CONAN: And those include?

MEGAN: Oh my God, from lychee to soy to wheat to yeast to gluten. The list is really long. You probably don’t want me to read the whole one.

CONAN: And what does that leave you eating?

MEGAN: You know, it has left me learning to cook, because I can’t go to restaurants or even get the processed food or even the soups at Whole Foods because they’d have garlic in them. So I’ve been learning to cook and adapt recipes to leave out the ingredients. (Unintelligible) in the morning and soup at lunch.

CONAN: After getting this rather ferocious list, I wondered if you considered a second opinion.

MEGAN: So what I’m doing is, starting January 1st, for the past month, I cut out all of these 30, 40 different foods. And now each week, I’m going to introduce a new food and see what I’m actually reacting to. And if I don’t have a reaction, as I’m keeping a log, then I can put the food back in my diet.

CONAN: But have you considered going, trying another doctor and saying is this a reasonable approach?

MEGAN: I haven’t. I have three different friends who’ve done this, one who last year they, the medical doctors had diagnosed her with maybe having a brain tumor. And after she did the same medical test and cut these foods out, she – a lot of her symptoms went away.

CONAN: And she’s doing well?

MEGAN: She’s doing really well. So went from a possible brain tumor to really being about food allergies.

CONAN: Megan, thanks very much for the call. And good luck. And good luck with the cooking, as well.

I wonder, Dr. Sharma, is this a reasonable approach? I mean, that seems like an awfully strong reaction.

Dr. SHARMA: It’s – well, I guess I’ll resort back to the guidelines because that’s what we’re here focusing on today. The guidelines make it pretty clear that as practitioners, we really should avoid doing these indiscriminate panels of testing to a number of different foods. And the reason is that there can be false-positive results or what is other called sensitization.

Sensitization means that when they do the blood test to look for the IGE, the allergic antibody to the food, they find the IGE to the food, but it could be that that the IGE really is having no clinical consequence at all in terms of an allergy.

And so many of us are walking around with IGE antibody in our blood, to a number of different foods, but we’re not allergic to that food. And really, the only true diagnosis of a food allergy is what happens when you eat the food.

CONAN: So that approach, cut them all out and then introduce one at a time and see what happens?

Dr. SHARMA: It could be. I mean, the symptoms of a food allergy that involves IGE are very clear. If you have a food allergy involving IGE, it won’t be presenting vaguely, as this did.

CONAN: All right. Stay with us, if you would. We’re talking with Dr. Hemant Sharma and also with Dr. Matthew Fenton about food allergies and new guidelines on how they’re diagnosed and treated. If you or your child suffer from food allergies, how did you and your doctor figure that out? Tell us your story, 800-989-8255. Email talk@npr.org. Stay with us. I’m Neal Conan. It’s the TALK OF THE NATION from NPR News.

(Soundbite of music)

CONAN: This is TALK OF THE NATION, from NPR News. I’m Neal Conan.

We’re talking today about food allergies. About one in 20 children have them, one in 25 adults. Those numbers seem to be rising. As of this past December, those with food allergies have new guidelines for diagnosis and management.

If that includes you and your child, how did you and your doctor figure it out? Give us a call: 800-989-8255. Email us: talk@npr.org. You can also join the conversation at our website. That’s at npr.org. Click on TALK OF THE NATION.

Just before the break, we had a caller, Megan, who was describing a panel of tests that she had done, a blood screening. And Dr. Matthew Fenton, chief of the Asthma, Allergy and Inflammation Branch in the Division of Allergy, Immunology and Transplantation at the National Institute of Allergy and Infectious Diseases – I got through it that time – wanted to come back on that.

Dr. FENTON: I think the caller raised a very important issue that’s very commonly seen among people who have food allergy or suspect they have food allergy. But it’s important to put it into context.

Food allergy afflicts about five percent of Americans. But 50 percent of Americans actually have some detectable level of the allergic IGE antibody against a food. So, far more people have some state of allergic sensitization than actually have clinical disease.

So what these test panels show you, a blood test, a RAST test or a skin test, is – tells you about the foods you’re sensitized to. And the danger, especially in children with suspected food allergy, is to not restrict the diet to the point where your nutrition is harmed.

It’s important to identify the allergen that actually causes symptoms and then work from there. And to identify that allergen, we, in the guidelines, recommend something called the oral food challenge, to precisely identify the causative food.

CONAN: Here’s an email we have from Beth in Greenville, Wisconsin: I’m in my 40s, and something has always stymied me and others that I’ve spoken to about this topic. When I was a kid, I don’t remember anybody in my school class that had allergies to such things as peanut butter, peanuts.

What happened between now and then? Why are there now more kids that have a serious enough allergy to peanut products that they’re banned from sending peanut butter and jelly sandwiches in school lunches?

Dr. Fenton, would you address that?

Dr. FENTON: We think at this point that the increase in food allergy that’s been seen over the past few decades reflects a similar increase in allergic diseases across the board – so asthma, hay fever, for example. We’ve seem similar rises.

Now, why this is occurring is really still scientifically a mystery. There’s certainly factors in the environment, factors in our lifestyle, factors in our diet that are involved. And one hypothesis that’s been put forward to help explain this is something called the hygiene hypothesis, that says as our environments and lifestyles get cleaner, and we are less exposed to microbes, and we use higher – antibiotics at a higher frequency, that our immune systems, in a sense, are looking for something to do. They’re not able to do their normal job, which is to fight off pathogens in the environment, because we have such a clean environment.

Now, that’s a somewhat naive hypothesis, but there are some very strong points to that that are likely to underlie the connection between the cleaner environment, the trend in increased allergic diseases and our immune system looking for something to do.

CONAN: Let’s introduce another voice in the conversation: Julia Bradsher, chief executive officer of the Food Allergy Anaphylaxis Network, a group that supports awareness and research on this subject. She also joins us here in Studio 3A.

Nice to have you with us today.

Ms. JULIA BRADSHER (Chief Executive Officer, Food Allergy Anaphylaxis Network): Thank you.

CONAN: And yours was one of the groups that urged the conduct of this new guideline?

Ms. BRADSHER: Yes, FAAN, the Food Allergy Anaphylaxis Network, was very instrumental in pushing for these guidelines so that families with food allergies could be better supported.

CONAN: And if there’s one misconception that people have about allergies, what would it be?

Ms. BRADSHER: I guess one of the greatest misconceptions is something that Dr. Fenton mentioned earlier, which is that people think that a food allergy is, you know, basically a sneeze or, you know, a cough: You eat something, and you sneeze.

But it’s really a potentially life-threatening condition. And, you know, people are walking around, you know, being exposed on a daily basis to a potential allergen that, if they consume it, it could be fatal.

CONAN: And just given the numbers that we were talking about earlier, is that emailer right? I mean, you know, entirely possible that 40 years ago, when she was in school, this didn’t seem to be a problem, and now it is.

Ms. BRADSHER: I talk to people all the time about food allergies, and one of the things I hear frequently is: When my child started, there was one child, mine, in a classroom. And today – you know, that was in kindergarten. Today, my child’s in the fifth grade, and there’s 10 children. So we hear this anecdotally all the time.

CONAN: President Obama signed the Food Allergy and Anaphylaxis Management Act into law at the beginning of last month, after five years pending in Congress. What changes is that going to portend?

Ms. BRADSHER: Well, the wonderful thing about getting the FAAMA passed and getting it signed into law is that we now have guidelines for the country for schools to manage food allergies in the schools.

CONAN: And that means we’re not going to see peanut butter in the cafeteria?

Ms. BRADSHER: What it means is that schools now have – no matter if it’s a school in California or a school in Virginia, those schools have uniform guidelines that they can go to to learn how to manage the food allergies in schools.

CONAN: All right, let’s get another caller on the line. And this is Derrick(ph), Derrick with us from Louisville.

DERRICK (Caller): Yeah, it’s Louisville, actually, west of the Mississippi.

CONAN: Oh, the wrong Louisville. I apologize. Louisville in Colorado. Go ahead.

DERRICK: That’s okay. Yeah, my son has a Latex allergy, and we discovered it when he was a baby, about 18 months old, and when he was doing an eczema study for some topical medication and his arms swelled up like a balloon right in front of our eyes at the doctor’s office. And it turned out it was because of the Latex gloves the nurses were wearing when they were taking blood draws.

And – so because it was a part of a study, we had to find out what exactly it was. It turns out, it was the Latex. And because of that, that protein crosses over into foods like bananas and cantaloupe and honeydew and kiwi and a whole list. And things we know, like bananas, he can’t really even touch without having an allergic reaction. It’s not about eating it. It’s just about coming into contact with it.

CONAN: Mm-hmm. And how does that change his life?

DERRICK: Well, he’s got an EpiPen that he’s got to have with him everywhere, and…

CONAN: That’s in case he needs an injection to save his life.

DERRICK: Yeah, right, right. Balloons for parties in the classroom, you know, Latex balloons, especially if they have a little powder inside of it, if it pops, then it floats around in the air. Or, you know, the foods that are mixed in a fruit salad. Usually, he can’t even touch a fruit salad, even though there may be, say, a strawberry that he could eat, but the cross-contamination is there.

So it’s – he’s really had to educate and be an activist – or not an activist, but, you know, speak up for himself and say, you know, I can’t eat that. I can’t touch that. And this needs to not be in my classroom because I don’t want to use my EpiPen.

CONAN: Yeah. Dr. Sharma, is this all too common?

Dr. SHARMA: It is. And what you’re describing, Derrick, is you used the exact right term. It’s cross-reactivity. And so there are – our bodies, oftentimes, our immune system will see proteins that are similar structurally in the same way. So the Latex protein that your son is reacting to is similar to some of the proteins that are present in these other fruits, like banana, kiwi, avocado, mango.

And so even touching a food can, in some children, cause a reaction. The route of exposure that most commonly will cause a reaction is ingestion, actually eating the food, but reactions can also occur through contact and, in rare cases, even through inhalational exposure.

CONAN: And Julie Bradsher, I wanted to ask you: That part about becoming his own advocate, that’s what your organization talks a lot about, too.

Ms. BRADSHER: Yeah. We do – we spend a lot of time talking with families about how to advocate for themselves, whether it’s in the school, in a restaurant, on an airline. You know, we – that’s an important factor. And for kids in particular, they really have to learn how to speak up for themselves. And, you know, I’ve met many parents, many children where the kids are actually very resilient. They’re incredibly great advocates for themselves.

CONAN: Derrick, how old is your son now?

DERRICK: He’s going to be 14 in two weeks. But – so he’s grown up with this, and, you know, being an advocate for himself, he’s really done well.

CONAN: And is this something he’s likely to grow out of? Is that what you’re told?

DERRICK: No. We’re told it’s a lifetime thing that he needs to be, you know, always watchful of.

CONAN: Well, we wish you and him the best of luck. Thanks very much for the call.

DERRICK: Yeah.

CONAN: There’s an email from Amy in Cincinnati: On a recent mission trip with my church to a township in South Africa, we were doing a children’s program and provided a snack. The snack the locals provided was a raisin-peanut trail mix. We immediately voiced our concern for peanut allergies with the kids, and the moms laughed at us. They’d never heard of such a thing. Are allergies more common in certain countries? Why is there not a peanut allergy problem in South Africa?

Dr. Fenton, is that the peck-of-dirt syndrome that we were talking about before?

Dr. FENTON: Well, that may be part of it in certain areas. But this geographical restriction of food allergies is really a fascinating phenomena. And clearly, if you take Africa as a whole, the continent has far less food allergies and far less asthma than the United States or Europe.

There was an interesting study that was completed last year in Europe called the EUROPREVAL study, which looked at allergies on a country by country basis. And what was really surprising was even within Europe, Western Europe, with a lot of commerce between various countries and the close geographic proximity, there was a huge variation from country to country, even within country, where one part of a country would have a particularly high incidence of peanut or soy allergy, and that would be very different from the adjoining country or even different parts of the same country.

So there are a lot of factors involved. Again, the environment, genetics, pollution, so many – and diet. So many different factors can play a role.

CONAN: Let’s go next to Melissa, Melissa with us from Brick Township in New Jersey.

MELISSA (Caller): Hi. Good afternoon.

CONAN: Good afternoon. Go ahead, please.

MELISSA: Yeah. I had a question for the doctor. My daughter is one. I have four children. And about six months ago, I gave her an egg to eat, and I noticed that her ears were turning up purplish. And, of course, I called the pediatrician. And it looks like hives, so she ordered a blood panel of, I guess, food allergy test (unintelligible) drew serums. And they found out that she was not allergic to eggs, but she was allergic to peanuts and tuna fish, which I had never exposed her to and – so it must have been a fluke thing of why her ears, you know, had broken out in that rash.

But my concern is the sensitivity level. She marked that it wasn’t severe. I think she said it was level two, if I remember. I don’t know how it’s actually measured. But is this something that if I keep her away from it, she’s likely to grow out of in the future, or is this something that, you know, if I keep her from being around anything with peanuts in it…

CONAN: Mm-hmm. Melissa, I’m going to refer your question to Dr. Sharma. But we have to say he can’t diagnose your daughter on the radio. This is very broad, generalized response.

MELISSA: Yeah.

CONAN: But, Dr. Sharma.

Dr. SHARMA: Thanks. Well, Melissa, unfortunately, I can’t speak more than in general terms. But these blood tests are helpful both at the time of diagnosis as well as in terms of giving some information about prognosis. And so oftentimes, we will repeat blood tests annually, perhaps more frequently depending on a specific circumstance, to look at the trend in the level and that can sometimes give us some information about whether a child is outgrowing given food allergy or whether it’s persisting. And the gold standard as Dr. Fenton had already alluded to is to do an oral food challenge in a supervised setting where that food is actually fed to the child and you observe for any signs of a reaction.

CONAN: All right. And Dr. Fenton.

Dr. FENTON: I wanted to follow up on what Dr. Sharma was mentioning because it seems to make common sense to most people that avoiding a food for a child who might have an allergic sensitization is the right thing to do.

But actually there is a lot of evidence to support that early consumption of those foods can actually prevent a food allergy. For example, in Israel, a country where young children are traditionally given a peanut-containing snack called Bamba, these children have an amazingly low rate of peanut allergy compared to other countries.

So we’ve actually taken a look at that, and the NIAID is funding a study that is looking at whether consumption or avoidance of peanut in early life is more protective against the eventual development of peanut allergy.

CONAN: Melissa, good luck with your daughter. Appreciate it.

MELISSA: Thank you. Thank you.

CONAN: Here’s an email. This is from Karen. Thirty years ago, I had a massive anaphylactic reaction within 10 to 15 minutes after consuming shrimp. My husband rushed me to a nearby hospital that he worked for. We were met in the parking lot by staff with the epinephrine in hand. I had airway compromise, massive hives over my entire body, including face and oral mucosa. Of course, I went for allergy testing following this episode. And the allergist at the University of Cincinnati decided after an exhaustive period of testing, I was likely allergic to what the shrimp ate. I carried an EpiPen for years but no longer do, and I eat shrimp often.

The exhaustive series of tests, and Dr. Sharma, so many patients complain about that. Why can’t we find out what the diagnosis is more easily?

Dr. SHARMA: It’s a great question. And the testing is moving forward. And I think with funding from organizations like the NIAID, we’re getting more refined diagnostic testing. And, eventually, we will have testing that has greater sensitivity and specificity. The specific question regarding this food; hard to know what exactly happened. There are cases of anaphylaxis which we call idiopathic. That means that it wasn’t related to anything that was eaten or in the environment, and the immune system just did it on its own. But it certainly – our hope is that, with time, we’ll have even better diagnostic tools.

CONAN: Let’s go next to Nathan, Nathan with us from Berkeley.

NATHAN (Caller): Hi. Yeah. I have an awful lot of questions. But if I restrict myself to one, the symptoms that I get – I talked to various doctors at various times and they don’t even have a name for this reaction. And, you know, in my case, I get bleeding blisters in my sinuses in my nose. Or from cranberries, I get blisters on the back of my neck and the back of my hands. And I was wondering, is this something that is just completely unfamiliar to physicians?

CONAN: Dr. Fenton, has this come up in your experience?

Dr. FENTON: Well, I think I’ll pump that one to Dr. Sharma since I’m not a physician.

CONAN: All right.

Dr. SHARMA: It’s often that we’ll see patients who have a variety of vague complaints. And they’re wondering, or sometimes worrying that they might have a food allergy. And so sometimes our job is to say that we don’t think this is a food allergy. And oftentimes that happens more in adults because it is unusual if we would have a new onset of food allergy with the exception, perhaps, of fish – to fish or shellfish later in adulthood. But these kinds of vague complaints, it’s difficult to connect them directly to food allergy.

CONAN: Is it vague to say, every time I eat cranberries I get hives at the back of my hands and at the back of my neck?

Dr. SHARMA: Well, that particular reaction I wasn’t referring to. But the bleeding and the oral ulcers, that’s not something that we commonly see with any particular kind of immune media, that food allergy. Hives certainly are one sign of a food allergic reaction where the allergic cells under the skin are releasing their chemicals causing the hives. And that can happen after certain foods. Cranberries are not one of the top eight food allergens. And groups like the NIAID and FAAN, we really try to focus our emphasis on the top eight food allergens, which are responsible for more than 90 percent of food allergies.

CONAN: And those eight are?

Dr. SHARMA: So milk, eggs, soy, wheat, peanut, tree nuts, fish and shellfish.

CONAN: Okay. It sounds like you got that list memorized. Thank you very much for the call, Nathan. And good luck at Thanksgiving.

In any case, thanks to Dr. Sharma – Dr. Hemant Sharma of the Food Allergy Program at the Children’s National Medical Center in Washington, D.C. Matthew Fenton, I’m not going to read your title again. But he’s with the National Institute of Allergy and Infectious Diseases, and Julia Bradsher of the Food Allergy Anaphylaxis Network.

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Why Are Asthma Rates Soaring?

Why Are Asthma Rates Soaring? Researchers once blamed a cleaner world. Now they are not so sure

Research into varying causes of asthma may eventually lead to new ideas on how to manage the condition.

According to an article published in the Scientific American, Asthma rates have been surging around the globe over the past three decades, and for a long time researchers thought they had a good idea of what might be fueling the increase: the world we live in is just a little too clean. According to this notion—known as the hygiene hypothesis—exposure in early childhood to infectious agents programs the immune system to mount differing highly effective defenses against disease-causing viruses, bacteria and parasites. Better sanitary conditions deprive the immune system of this training, so that for reasons that are still unclear, the body pounces on harmless particles—such as dust and ragweed—as if they were deadly threats. The resulting allergic reaction leads to the classic signs of asthma: chronic inflammation or swelling of the airways and acute spasms of those passageways.

Or so the thinking went. Although a lot of data support the hygiene hypothesis for allergies, the same cannot be said for asthma. Contrary to expectations, asthma rates have skyrocketed in urban areas in the U.S. that are not particularly clean. Moreover, the big increase in asthma rates in developed countries did not kick off until the 1980s—well after general sanitary conditions in the richer parts of the world had improved. And some studies are beginning to show that far from protecting children from asthma, respiratory infections in early childhood may actually be a risk factor for it.

The collapse of the hygiene hypothesis as a general explanation for the startling jump in asthma rates has led physicians and scientists to a new realization: asthma is a much more complex condition than anyone had truly appreciated. Indeed, it may not be even be a single disease. Studies now suggest that only half of asthma cases have an allergic component.

The prevention and treatment implications are significant. If, for instance, it is true that allergy is not a fundamental cause of asthma in many people, then an alternative mix of treatments may be more effective for those individuals. To root out asthma’s cause (or causes) and properly treat the burgeoning number of people who are affected—300 million globally at last count—scientists will have to come to grips with the biology of its various forms.

Balancing Act
The hygiene hypothesis was first described in 1989 by David P. Strachan, a British epidemiologist who was studying hay fever. The more children in a family, he noticed, the lower the rates of hay fever and eczema, an allergic skin condition. Children in large families tend to swap colds and other infections more often than children with fewer siblings. Could it be that increased exposure to pathogens from their many siblings was protecting children from large families against allergies?

That same year Erika von Mutius, an epidemiologist at Munich University, was looking into the effect of air pollution on asthma in what was then East and West Germany. Children from dirtier East Germany, she was shocked to find, had dramatically less asthma than their West German counterparts living in cleaner, more modern circumstances. The East German children, unlike their Western counterparts, had spent more time in day care and thus had likely been exposed to many more viruses and bacteria. “That was astonishing,” she recalls, and led to “a major shift” in thinking.

These findings sparked intense debate among scientists. What is it about unhygienic living that might protect against asthma? One of the more popular explanations in the following decades entailed a balance between the immune cells that are involved in the body’s reaction to most viruses and bacteria and those that are involved in the reaction to most parasites and allergens. These two groups of cells produce chemicals that inhibit each other. Early-childhood exposure to bacteria and viruses would cause the infection-related cells to become active, keeping the allergy- and parasite-related cells in check. Without that interplay, the allergy-related cells would later become over­reactive, starting an allergic chain reaction that became chronic and ended in constricted airways, asthmatic spasms and labored breathing.

Inconvenient Facts
There was only one problem. As more data came in, they failed to tell the same story as the hygiene hypothesis. Children in Latin America with high rates of supposedly protective infection have even higher rates of asthma than children in western Europe. Inner-city children in Chicago and New York have quite high rates of asthma, despite unhygienic living. And the rates of asthma varied among countries with very similar histories of cleanliness—indicating that there was more to it than tidiness. For example, by 2004 Sweden’s asthma cases had increased to 10 percent, according to one international study, while the number of cases in the U.K. had soared to 20 percent.

In addition, research showed that the relation between asthma and allergy is not at all straightforward. Some cases of asthma are indeed triggered by allergies, although the consensus among researchers over the past decade is that the connection is probably not as clear-cut as the hygiene hypothesis would suggest. Still other layers of immune regulation must be involved. Maria Yazdanbakhsh, a parasitologist at Leiden University in the Netherlands, has shown that people infected with parasitic worms have very high levels of the allergy-related immune cells but very low rates of asthma, disproving a direct connection between allergy and asthma in these cases at least.

What is more, a landmark review of asthma studies in 1999 by Neil Pearce, now at the London School of Hygiene and Tropical Medicine, demonstrated that at least half of asthma cases in the general population have no connection to allergic reactions at all. These could never be explained by the hygiene hypothesis.

In fact, the same factors that the hygiene hypothesis suggests protect people from developing allergic asthma may cause them to develop nonallergic asthma. “We think that dirt protects against allergic asthma, as foretold by the hygiene hypothesis, but increases the risk of having a nonallergic form,” says Laura Rodrigues of the London School of Hygiene and Tropical Medicine, who studies asthma in Latin America. Pollutants in the air can irritate the airways and cause inflammation that leads to constricted breathing. Childhood colds, which the hygiene hypothesis suggested might help prevent development of asthma, can actually be a risk factor for asthma, especially if severe, says James E. Gern, a pediatrician who studies colds and asthma at the University of Wisconsin–Madison. “Early-life infections are an indicator of asthma risk rather than protective in any way,” he says.

Besides the hygiene hypothesis, what can explain the increase in asthma rates? Other suggested causes include a rise in sedentary lifestyle, which could affect lung strength, and the rise in obesity, which increases inflammation throughout the body. A reworking of the hygiene hypothesis that focuses on changes in the normal nondisease-causing bacteria that live inside and on the body (in the intestines or the airways or on the skin) has promise. Studies by von Mutius and others have shown that children who live on farms where cows or pigs are raised and where they drink raw milk almost never have asthma, allergic or otherwise. Presumably because the children drank unpasteurized milk and handled livestock, they have different strains of normal bacteria in their airways that are somehow more protective than those found in city kids.

But the short answer to the question of why asthma has increased, according to Pearce, von Mutius, Rodrigues and many others, is, “We don’t know.” Pearce, in particular, wonders whether modernization in general or westernization in particular may play a role. “There is something about westernization that means people’s immune systems function in a different way,” he says. “But we don’t know what the mechanism is.”

Getting at the true underlying cause of the climb will require better ways of distinguishing among various possible types of asthma. Major asthma research networks supported by the National Institutes of Health have begun recording the details of thousands of individuals’ symptoms and treatments. As the results are gathered and analyzed, researchers hope to identify clusters of asthma cases that have different causes and respond to different treatments. The hope is that “if you come in with these characteristics in asthma, we can anticipate what the prognosis is going to be and what the most effective treatment for you is going to be,” says William W. Busse of the University of Wisconsin School of Medicine and Public Health, who is part of one such network.
It will take years to understand fully whether microbial exposure, lifestyle changes or the obesity epidemic is more important in explaining the continuing increase in asthma rates. But one thing is clear: the hygiene hypothesis was just the beginning.

To subscribe to the Scientific American and for more information about the Asthma article visit http://www.scientificamerican.com/article.cfm?id=why-are-asthma-rates-soaring&page=3

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Richmond is Top U.S. “Asthma Capital”

Richmond is Top U.S. “Asthma Capital” Again says Annual Report Names the 100 Most Challenging Places to Live with Asthma

For the second year in a row, Richmond, VA, has been ranked as the No.1 Asthma Capital – the most challenging place to live with asthma in the U.S. – according to the Asthma and Allergy Foundation of America (AAFA), which conducted the study. The ranking was determined based on an analysis and scoring of a variety of factors in the 100 largest U.S. metro areas.

For eight years, AAFA has scientifically researched and evaluated conditions in metropolitan areas in America and ranked them based on quality of life for people with asthma. The Foundation reviews 12 factors including: crude death rate for asthma; estimated prevalence of adult and pediatric asthma; risk factors, such as air pollution, pollen counts and public smoking bans; and medical factors, such as the number of asthma medications used per patient and the number of asthma specialists in the area. The full report showing all 100 metro areas is available for free at www.AsthmaCapitals.com.

Going South

Up from number fourteen in 2009, to number 1 in 2010, Richmond is again ranked as the top Asthma Capital in the 2011 report. The dubious honor for Richmond is due to a number of factors including a higher than average pollen score, continued poor air quality, a lack of public smoking bans, high poverty and uninsured rates, and other factors.

In fact, 14 cities in the top 25 of this year’s rankings are located in the south. The poor ranking of southern cities this year may be due in part to the slow adoption of “100% smoke-free” laws in southern tobacco-producing states and cities, as well as continued high levels of air pollution and ozone days, all considered major risk factors for people with asthma.

Don’t Move – Improve

More than 20 million children and adults live with asthma all over the U.S., making it one of the most common and costly diseases. Experts agree that people can’t move away from their asthma since every city in America has a variety of risk factors. Instead, people should work with an asthma specialist to improve their overall asthma management plan no matter where they live.

“Although Richmond is a particularly difficult place for people with asthma to live, asthma triggers are present in every American city,” says Mike Tringale, AAFA’s Vice President of External Affairs. “There is no way for asthma patients to escape their disease, but no matter where they live, patients can work with their physicians to find ways to control their symptoms better.”

This Year’s Top 10

The top 10 Asthma Capitals for 2011 are:

1. Richmond, VA
2. Knoxville, TN
3. Memphis, TN
4. Chattanooga, TN
5. Tulsa, OK
6. St. Louis, MO
7. Augusta, GA
8. Virginia Beach, VA
9. Philadelphia, PA
10. Nashville, TN

Find the full rankings and complete data for all 100 cities at www.AsthmaCapitals.com.

About Asthma

Asthma is a condition characterized by inflammation of airways in the lungs resulting in chronic wheezing, coughing and difficulty breathin

• More than 4,000 deaths annually

• More than 500,000 hospitalizations annually
• Over 12 million missed days of school for children each year
• Over 10 million missed days of work for adults each year
• 1.8 million emergency room visits each year
• $18 billion in medical expenses and indirect costs each year

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Asthma and Food Allergies

Asthma and Food Allergies: Children, Males and Blacks are at increased risk for Food Allergies says new NIH Study

A new study estimates that 2.5 percent of the United States population, or about 7.6 million Americans, have food allergies. Food allergy rates were found to be higher for children, non-Hispanic blacks, and males, according to the researchers. The odds of male black children having food allergies were 4.4 times higher than others in the general population.

The research, which was funded by the National Institutes of Health and appears in the Journal of Allergy and Clinical Immunology, is the first to use a nationally representative sample, as well as specific immunoglobulin E (IgE) or antibody levels to quantify allergic sensitization to common foods, including peanuts, milk, eggs, and shrimp. The hallmark of food allergy is production of IgE antibodies to a specific food protein. Once IgE antibody is made, further exposure to the food triggers an allergic response. IgE levels are often high in people with allergies.

“This study is very comprehensive in its scope. It is the first study to use specific blood serum levels and look at food allergies across the whole life spectrum, from young children aged 1 to 5, to adults 60 and older,” said Darryl Zeldin, M.D., acting clinical director at the NIH’s National Institute of Environmental Health Sciences (NIEHS) and senior author on the paper. “This research has helped us identify some high risk populations for food allergies.” In addition to the identification of race, ethnicity, gender, and age as risk factors for food allergies, the researchers also found an association between food allergy and severe asthma.

Food allergy rates were highest (4.2 percent) for children 1 to 5 years. The lowest rates (1.3 percent) were found in adults over the age of 60. The prevalence of peanut allergies in children aged 1 to 5 was 1.8 percent and in children aged 6 to19, it was 2.7 percent. In adults, the rate was 0.3 percent.

The odds of patients with asthma and food allergies experiencing a severe asthma attack were 6.9 times higher than those without clinically defined food allergies.

“This study provides further credence that food allergies may be contributing to severe asthma episodes, and suggests that people with a food allergy and asthma should closely monitor both conditions and be aware that they might be related,” said Andrew Liu, M.D., of National Jewish Health and the University of Colorado School of Medicine, Denver, and lead author on the paper.

The data used for the study comes from the National Health and Nutrition Examination Survey (NHANES) 2005-2006. NHANES is a large nationally representative survey conducted by the National Center for Health Statistics, a part of the Centers for Disease Control and Prevention.

Zeldin and Liu note more research is needed to understand why certain groups are at increased risk for food allergy. The authors comment in the paper that food allergies may be under-recognized in blacks, males, and children, because previous studies relied on self-reporting and not food-specific serum IgE levels.

“Having an accurate estimate of the prevalence of food allergies is helpful to public health policy makers, schools and day care facilities, and other care providers as they plan and allocate resources to recognize and treat food allergies,” said Linda Birnbaum, Ph.D., NIEHS director.

The National Institutes of Health (NIH) — The Nation’s Medical Research Agency — includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases.

Reference: Liu AH, Jaramillo R, Sicherer SH, Wood RA, Bock SA, Burks AW, Massing M, Cohn RD, Zeldin DC. National prevalence and risk factors for food allergy and relationship to asthma: Results from the National Health and Nutrition Examination Survey 2005-2006. J Allergy Clin Immunol. DOI: 10.1016/j.jaci.2010.07.026.