Category: Asthma and Molds

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World Asthma Day Summary

On the day after World Asthma Day, May 3, 2022, we scanned the globe to find a statement that best sums up the current state of affairs regarding Asthma.

Kudos to tbe U.S National Institute of Environmental Health NIH Statement on World Asthma Day 2022: Toward Improved Asthma Care

Good enough of summary that we want to publish this in its entirety.

Asthma is a serious lung disease; causes chest tightness, wheezing, and coughing; can often be controlled with proper treatment.

Today (May 3, 2022) on World Asthma Day, the National Institutes of Health reaffirms its commitment to biomedical research aimed at preventing the onset of asthma, understanding its underlying causes, and improving the treatment of it. This chronic airway disease, which is characterized by periodic worsening of inflammation that can make it hard to breathe, affects more than 25 million people in the United States, including more than 5 million children. Left untreated, it can be life-threatening.

While scientists have made substantial progress in understanding asthma diagnosis, management, and treatment, therapies to permanently improve breathing for those who suffer from asthma remain elusive. Researchers around the globe are working steadily toward this goal while they seek to better understand and find new ways to manage the disease. They also are continuing research on the underlying causes of disparities in the incidence, care, and prevention of the disease. On the heels of recently updated management and treatment guidelines, researchers anticipate a brighter future for people living with asthma.

Three NIH institutes primarily support and conduct studies on asthma — the National Heart, Lung, and Blood Institute (NHLBI); the National Institute of Allergy and Infectious Diseases (NIAID); and the National Institute of Environmental Health Sciences (NIEHS). Other NIH Institutes and Centers also support and conduct asthma research. NIH scientists and grantees made important advances in understanding, treating, and managing asthma in 2021, which are briefly highlighted as follows:

Asthma and COVID-19

An NHLBI-funded study showed that during the pandemic, asthma attacks, also known as asthma exacerbations, significantly decreased in a large group of children and adolescents, compared to the year before the pandemic. The study also found that telehealth visits among these patients increased dramatically during this time. The study included nearly 4,000 participants aged 5-17 years with a prior diagnosis of asthma. Researchers believe a better understanding of the factors that contributed to these improved outcomes could lead to better asthma control in all children and adolescents, as researchers noted no racial or ethnic differences in health outcomes in this population.

A NIAID-funded study found that asthma does not increase the risk of becoming infected with SARS-CoV-2, the virus that causes COVID-19. This finding came from a six-month household survey of more than 4,000 children and adults conducted between May 2020 and February 2021.

Asthma Disparities

Researchers have known for decades that social determinants of health – conditions like housing, neighborhood, education, income, and healthcare access – can affect the quality of life and asthma-related health outcomes of people living with the disease. NIH scientists are now reporting new advances in understanding the relationship between social determinants of health and asthma.

Black and Hispanic children who live in low-income urban environments in the United States are at particularly high risk for asthma attacks. These children tend to be underrepresented in large trials of new biologic therapies for asthma.

In a recent NIAID-supported clinical trial, the monoclonal antibody mepolizumab decreased asthma attacks by 27% in Black and Hispanic children and adolescents who have a form of severe asthma, are prone to asthma attacks, and live in low-income urban neighborhoods.

In one study, NHLBI-funded investigators demonstrated the importance of housing interventions in improving the health of children with asthma. Poor quality housing is associated with a high level of asthma triggers – including mold, cockroach, mouse, and dust mite allergens – that can pose a health threat to children with asthma. The study showed the feasibility of using targeted interventions – including better pest management, improved ventilation, and moisture reduction – to achieve healthy housing. It showed that such interventions can result in reduced symptoms and hospitalizations due to asthma.

Environmental Exposures and Asthma

Researchers have known for years that asthma can be triggered by substances in the indoor and outdoor environment. New research shows that exposure to some asthma triggers might even occur before birth.

In an NIH-supported study that included grant support from NIEHS and the NHLBI, researchers reported that prenatal exposure to tiny air pollution particles significantly increased the risk for developing asthma in children. The study, which analyzed data from two different study cohorts, focused on a group of mothers and their children, mostly Black or Hispanic, in the Boston area who lived near major roadways with heavy traffic. It found that more than 18% of the children who were exposed to high levels of these so-called ultrafine particles in the womb developed asthma in their preschool years, compared to 7% of children overall in the United States.

An NIEHS clinical study will assess how environmental factors affect disease progression in non-smoking adults who have moderate or severe asthma. The study will focus on the microbiological and genetic factors associated with atopic asthma, also known as allergic asthma, which is triggered by pollen, dust mites, and other allergens. A better understanding of this data might lead to improved treatments for people with this type of asthma, researchers say.

Climate Change and Asthma

Studies have shown that climate change can increase air pollutants such as ground-level ozone, fine particulates, wildfire smoke, and dust, and that these pollutants can exacerbate asthma. Climate change can also affect the production, distribution, and severity of airborne allergens.

NIEHS, NHLBI, and other NIH institutes and centers are leading the NIH Climate Change and Health Initiative. This is a cross-cutting NIH effort to reduce health threats such as asthma that can develop or worsen because of climate change. The initiative will look at these threats across the lifespan and find ways to build health resilience in individuals, communities, and nations around the world. A strategic framework for the Initiative will help guide NIH investments in this area.

An NIEHS-funded study provides examples of how extreme weather events can affect asthma outcomes. For example, as heat waves and droughts become more frequent and prolonged, the risk of large wildfires will likely increase, resulting in poor air quality that makes it more difficult to control asthma. Other climate-change events can lead to longer and more intense pollen seasons, while mold and dampness in homes may cause asthma to develop or worsen preexisting cases.

About the National Institute of Allergy and Infectious Diseases (NIAID): NIAID conducts and supports research—at NIH, throughout the United States, and worldwide—to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID website.

About the National Heart, Lung, and Blood Institute (NHLBI): NHLBI is the global leader in conducting and supporting research in heart, lung, and blood diseases and sleep disorders that advances scientific knowledge, improves public health, and saves lives. For more information, visit www.nhlbi.nih.gov. For additional information about NHLBI’s asthma resources, visit https://www.nhlbi.nih.gov/BreatheBetter.

About the National Institute of Environmental Health Sciences (NIEHS): NIEHS supports research to understand the effects of the environment on human health and is part of the National Institutes of Health. For more information on NIEHS or environmental health topics, visit

About the National Institutes of Health (NIH): 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. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

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Asthma and Environmental Fungi – interview with Marie-Claire Arrieta Ph.D.

World Asthma Foundation “Defeating Asthma Series uncovers New Hope for Asthma Managementant

Our understanding of Asthma and the way we treat it may soon be radically different from what currently exists, due to new research on the human microbiome and how the microbiome affects asthma.

In this interview with Marie-Claire Arrieta Ph.D, Assistant Professor Depts. of Physiology and Pharmacology & Pediatrics Cumming School of Medicine University of Calgary Health Research Innovation Centre, Calgary, Alberta, Canada we learn that:

  • A significant proportion of asthmatics have severe asthma that also cannot be controlled easily with the current treatments
  • The microbiome is not only bacteria just like other ecosystems. Not only bacteria but they’re mix including environmental fungi
  • The microbiome is full of viruses as well

Interview

World Asthma Foundation: Dr. Arrieta, what prompted your research in this area?

Dr. Arrieta: As you know, asthma has no known cures. A significant proportion of asthmatics have severe asthma that also cannot be controlled easily with the current treatments, so we’re trying to figure out ways of improving both the prevention and the potential therapies for asthma. We also know that asthma has become an epidemic disease in Canada. At least it’s quadrupled in incidence over only 30 years, and we know that it’s mainly environmental factors that are explaining or possibly explaining this really great increase in incidence for asthma.

We’ve come to learn in the past 10 years that the microbiome is implicated. The gut microbiome is this very large community of microbes that we all harbor in our inner guts. However, The vast majority of these studies of the microbiome and asthma have only included bacteria, including studies that I have participated in before. This only provides a part of the view of this vast variety of microbes that we know inhabit this microbial ecosystem.

The microbiome is not only bacteria just like other ecosystems. Not only bacteria but they’re mixed, and they definitely include fungi. We thought that studying the role of fungi would be important because molds and environmental fungi are quite common triggers of asthma attacks in asthmatics, also for people with allergies. This, we thought, may suggest that the fungi in the microbiome, that no one has been studying much before, may be involved in some of the immune education that happens early in life that may later in childhood lead to this uncontrolled inflammation in the airways towards environmental fungi, along with other environmental triggers of asthma. That’s why we wanted to look at fungi.

World Asthma Foundation: Excellent. Great study. I’m most impressed. What are some of the key findings?

Dr. Arrieta: We found by giving specific species or types of fungi and/or bacteria to mice, and we used a specific type of mouse known as the germ-free mouse. These are mice that are kept completely devoid of microbes, so they’re like a blank state that you can associate with microbes in a way that would allow you to then make good conclusions from the experiment.

We found that fungi have a very important role in the way the microbiome establishes early in life. When I say microbiome, now I mean a combination of both bacteria and fungi. We also found that fungi are sensed by the immune system differently than bacteria in a way that they seem to amplify the immune response. For example, we found that mice that were colonized only with fungi were more susceptible to asthma.

World Asthma Foundation: Interesting. Along with that, what were some of the other key findings?

Dr. Arrieta: The story’s definitely developing. This study was certainly a proof of concept, but based on this work as well as others that are starting to look at fungi too, we think that when fungi in the intestine of babies bloom, for example, during an antibiotic treatment, this may change the way the immune system responds to this microbiome that is now higher in proportion with certain fungi. This may also increase the susceptibility to those immune alterations that can later lead to asthma in certain people.

World Asthma Foundation: Interesting. I noticed that you mentioned several references to Candida albicans. How does that fit into the mix?

Dr. Arrieta: We don’t know yet. We chose Candida because it’s a very common yeast in our guts. Virtually everyone would have some candida in their bodies, not just in their guts, but it’s a very common inhabitant. Because of that, we wanted to use a species that was common. We found that Candida certainly can outgrow during antibiotic treatments. It may be one of the species implicated, but we’re not there yet. We’re now trying more species of fungi. In fact, we started a new set of experiments based on an infant clinical study that we just completed that showed us exactly which are the yeast and fungal species that bloom when babies are given antibiotics.

This was an interesting clinical study. We ran it at the emergency department of one of our children’s hospitals where we enrolled babies under six months of age, that for one reason or another had to take an antibiotic. This is a very common occurrence for infants. Then what we did was that we followed the microbiome during this antibiotic treatment, and we were able to identify the most common yeasts that seem to outgrow during the antibiotic treatment. We’re focusing on those, and surprisingly, Candida is not one of those all the time. It seems that, of course, Candida is there, but there’s other fungi that are able to outcompete other ones including Candida. Those are the ones that we’re focusing on now.

World Asthma Foundation: Thank you for that. By outcompete, the suggestion or the inference would be that the imbalance of fungi and bacteria are what’s causing the inflammation process?

Dr. Arrieta: That could be that case. That will be the next step, but as I said, the story is very much developing. I think we’re one of the first ones, but we’re not the only ones interested in studying the fungal component of the microbiome and how it relates to allergies and asthma. I think that in the next couple of years we’re going to learn a lot more.

World Asthma Foundation: Fair enough. What implications are there for asthma? Asthma rates are on the rise. What would you like asthmatics to know about your study?

Dr. Arrieta: For now, because the study is developing, I think what we know for sure is that the gut microbiome during early life is extremely important when it comes to, in general, immune development. Because asthma, of course, is an immune disease, these changes in the gut microbiome can certainly determine a baby’s risk to develop this disease, especially as we now understand in families that have a familial history of asthma as well.

What is important to asthmatics to know? There are certain lifestyle, changes, or behaviors that are now being recommended, including natural birth if, of course, is safe and possible, the use of breast milk over formula if it is possible. One of the things that we’re learning more about is that one of the ways to foster a healthy microbiome early in life is when babies start eating solid foods to make the diet as healthy as possible, the way nutritionists have been asking as to do so for decades now because this will foster a varied microbiome.

World Asthma Foundation: Good point. A fair amount of adult asthmatics suffer from fungal issues relative to lung inflammation and infection. Any thoughts on that?

Dr. Arrieta: There’s a couple of clinical studies, and I wish I remember from the top of my head the name of the drug exactly, that is being tested right now. I’m by no means, involved in this. I have just been reading it with great interest because it is an immune modulator. It’s a biological drug that targets some of the immune mechanisms that we now know recognize fungi. It’ll be really interesting to see now from the point of view of these patients, both children, and adults, that have fungal asthma, if this is really going to change their treatment options because as you know, those asthma tend to be more severe and harder to treat as well.

World Asthma Foundation: What would you like the scientific community to know about your research?

Dr. Arrieta: That within this revolution of studying that microbiome, I think we’re missing out by only focusing on bacteria. There’s a great deal that I have learned from my colleagues in microbial ecology. I am not an ecologist, but I started to partner up with them because of the methods and the concepts, and scientific frameworks that they used to study the microbiome. The microbiome is an ecosystem, and we have experts that have been studying ecosystems for decades before biomedical researchers started to study ecosystems. The inclusion of fungi, I think, will get us more answers. Also, the inclusion of other microorganisms that very few people, if any, are considering right now in the context of asthma research, which are viruses, very popular of course now because we’re under a pandemic. The microbiome is full of viruses and children experience many viral infections during the first year of life or the first two years of life. How does the immune system react to that? How does it get educated? I think that using a broader, more ecologically informed approach to study the microbiome is a lesson that I have learned over the years and I hope that others follow suit too.

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Asthma and Mold

Preventive Mold Strategies for Asthmatics

Several molds that grow both indoors and outdoors, produce allergenic substances. These allergens can be found in mold spores and other fungal structures (e.g. hyphae). There is no definite seasonal pattern to molds that grow indoors. However outdoor molds are seasonal, first appearing in early spring and thriving until the first frost.

Indoor molds are found in dark, warm, humid and musty environments such as damp basements, cellars, attics, bathrooms and laundry rooms. They are also found where fresh food is stored, in refrigerator drip trays, garbage pails, air conditioners and humidifiers.

Outdoor molds grow in moist shady areas. They are common in soil, decaying vegetation, compost piles, rotting wood and fallen leaves.

Preventive Strategies

* Use a dehumidifier or air conditioner to maintain relative humidity below 50% and keep temperatures cool.
* Vent bathrooms and clothes dryers to the outside, and run bathroom and kitchen vents while bathing and cooking.
* Regularly check faucets, pipes and ductwork for leaks.
* When first turning on home or car air conditioners, leave the room or drive with the windows open for several minutes to allow mold spores to disperse.
* Remove decaying debris from the yard, roof and gutters.
* Avoid raking leaves, mowing lawns or working with peat, mulch, hay or dead wood. If you must do yard work, wear a mask and avoid working on hot, humid days.

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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.
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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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Why Does Flu Trigger Asthma?

Why Does Flu Trigger Asthma? Study suggests new therapeutic targets for virally-induced asthma attacks

When children with asthma get the flu, they often land in the hospital gasping for air. Researchers at Children’s Hospital Boston have found a previously unknown biological pathway explaining why influenza induces asthma attacks. Studies in a mouse model, published online May 29 by the journal Nature Immunology, reveal that influenza activates a newly recognized group of immune cells called natural helper cells – presenting a completely new set of drug targets for asthma.

If activation of these cells, or their asthma-inducing secretions, could be blocked, asthmatic children could be more effectively protected when they get the flu and possibly other viral infections, says senior investigator Dale Umetsu, M.D., Ph.D., of Children’s Division of Immunology.

Although most asthma is allergic in nature, attacks triggered by viral infection tend to be what put children in the hospital, reflecting the fact that this type of asthma isn’t well controlled by existing drugs.

“Virtually 100 percent of asthmatics get worse with a viral infection,” says Umetsu. “We really didn’t know how that happened, but now we have an explanation, at least for influenza.”

Natural helper cells were first, very recently, discovered in the intestines and are recognized to play a role in fighting parasitic worm infections as part of the innate immune system (our first line of immune defense).

“Since the lung is related to the gut – both are exposed to the environment – we asked if natural helper cells might also be in the lung and be important in asthma,” Umetsu says.

Subsequent experiments, led by first authors Ya-Jen Chang, Ph.D., and Hye Young Kim, Ph.D., in Umetsu’s lab, showed that the cells are indeed in the lung in a mouse model of influenza-induced asthma, but not in allergic asthma. The model showed that influenza A infection stimulates production of a compound called IL-33 that activates natural helper cells, which then secrete asthma-inducing compounds.

“Without these cells being activated, infection did not cause airway hyperreactivity, the cardinal feature of asthma,” Umetsu says. “Now we can start to think of this pathway as a target – IL-33, the natural helper cell itself or the factors it produces.”

Personalized medicine in asthma?

The study adds to a growing understanding of asthma as a collection of different processes, all causing airways to become twitchy and constricted. “In mouse models we’re finding very distinct pathways,” Umetsu says.

Most asthma-control drugs, such as inhaled corticosteroids, act on the best-known pathway, which involves immune cells known as TH2 cells, and which is important in allergic asthma. However, Umetsu’s team showed in 2006 that a second group of cells, known as natural killer T-cells (NKT cells), are also important in asthma, and demonstrated their presence in the lungs of asthma patients. NKT cells, they showed, can function independently of TH2 cells, for example, when asthma is induced with ozone, a major component of air pollution. Compounds targeting NKT cells are now in preclinical development.

The recognition now of a third pathway for asthma, involving natural helper cells, may reflect the diversity of triggers for asthma seen in patients.

“Clinically, we knew there were different asthma triggers, but we thought there was only one pathway for asthma,” Umetsu says, adding that all of the identified pathways can coexist in one person. “We need to understand the specific asthma pathways present in each individual with asthma and when they are triggered, so we can give the right treatment at the right time.”

The study was funded by the National Institutes of Health.

Children’s Hospital Boston is home to the world’s largest research enterprise based at a pediatric medical center, where its discoveries have benefited both children and adults since 1869. More than 1,100 scientists, including nine members of the National Academy of Sciences, 12 members of the Institute of Medicine and 13 members of the Howard Hughes Medical Institute comprise Children’s research community. Founded as a 20-bed hospital for children, Children’s Hospital Boston today is a 395 bed comprehensive center for pediatric and adolescent health care grounded in the values of excellence in patient care and sensitivity to the complex needs and diversity of children and families. Children’s also is the primary pediatric teaching affiliate of Harvard Medical School. For more information about research and clinical innovation at Children’s, visit: http://vectorblog.org.

CONTACT:
Erin McColgan
Children’s Hospital Boston
617-919-3110
erin.mccolgan@childrens.harvard.edu

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Asthma and Fungai

Anti-Fungal Drug Offers Great Benefits to Some with Severe Asthma

January 1, 2009 — Some patients with severe asthma who also have allergic sensitivity to certain fungi enjoy great improvements in their quality of life and on other measures after taking an antifungal drug, according to new research from The University of Manchester in England.

The findings were reported in the first issue for January of the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.

“We knew that many people with severe asthma are sensitized to several airborne fungi which can worsen asthma without overt clinical signs. The question was: does antifungal therapy provide any clinical benefit,” said David Denning, F.R.C.P., F.R.C.Path., professor of medicine and medical mycology at The University of Manchester and lead investigator of the study.

In 2006, the most recent year for which official statistics are available, there were more than 16 million adults with self-reported asthma in the U.S.; about 20 percent of them have severe asthma.

A small number of severe asthmatics—about one percent— are known to have a syndrome called allergic bronchopulmonary aspergillosis, an extreme allergy to Aspergillus fumigatus fungus that is associated with the long-term colonization of their respiratory tracts with the fungus. But many more — 20 to 50 percent— are sensitized to a variety of fungi without showing overt clinical signs or demonstrable colonization. It is these patients with severe asthma with fungal sensitization, or “SAFS”, as the researchers named the syndrome, who are most likely to enjoy marked improvement with the antifungal therapy.

In the prospective double-blind study, 58 patients with severe asthma and allergic sensitivity to at least one of seven different common fungi (confirmed by a skin-prick test and/or an IgE blood test for the study) were randomized to receive either an oral dose of itraconazole (200mg twice a day) or a placebo.

After 32 weeks of treatment, 18 of the 29 patients (62 percent) who were randomized to receive the drug experienced significant improvements on their Asthma Quality of Life Questionnaires, and in runny nose and morning lung function. However, 11 of the patients who received the drug left the trial before completion, some citing side effects that included nausea, breathlessness and muscle weakness. Unfortunately, four months after stopping antifungal treatment, symptoms had returned.

“This study indicates that fungal allergy is important in some patients with severe asthma, and that oral antifungal therapy is worth trying in difficult-to-treat patients. Clearly itraconazole will not suit everyone and is not always helpful, but when it is the effect is dramatic,” said Dr. Denning. “These findings open the door to a new means of helping patients with severe asthma, and raise intriguing questions related to fungal allergy and asthma.”

John Heffner, M.D., past president of the ATS, reflected that the recent Severe Asthma Research Program report describes severe asthma as a entirely different form of the disease. “Patients with severe asthma may have unique triggers for bronchospasm, which remain unidentified. This study suggests that colonization with fungal species may generate immunologic responses in patients with asthma that perpetuate airway inflammation and blunt the effectiveness of drug therapy. One can’t help but wonder if antifungal therapy would benefit all severe asthmatics regardless of sensitivity to fungi.”

A press release provided by the American Thoracic Society — the world’s leading medical association dedicated to advancing pulmonary, critical care and sleep medicine.

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Asthma and Molds

<'h2>Asthma and Molds – Potential health effects and symptoms associated with mold exposures include allergic reactions, asthma, and other respiratory complaints.

Mold Resources

The publication, “A Brief Guide to Mold, Moisture, and Your Home”, is available in HTML and PDF (PDF, 20 pp, 278KB About PDF) [EPA 402-K-02-003]

Una Breve Guía para el Moho, la Humedad y su Hogar está disponible en el formato PDF (PDF, 20 pp, 796KB About PDF). [Documento de la agencia EPA número 402-K-03-008]

The publication, “Mold Remediation in Schools and Commercial Buildings”, is available in HTML and PDF (PDF, 54 pp, 5MB About PDF) [EPA 402-K-01-001, March 2001]

Resource: WHO Guidelines for Indoor Air Quality: Dampness and Mould (PDF) (248 pp., 2.65 M) exiting epa World Health Organization, 2009

EPA’s Office of Research and Development Fact Sheet: The Environmental Relative Moldiness Index

Order publications from EPA’s NSCEP. Use the EPA Document Number when ordering.

Contents

* Introduction to Molds
* Basic Mold Cleanup
* Ten Things You Should Know About Mold
* Asthma and Mold
* Floods/Flooding
* Health and Mold
* Homes and Mold
* Indoor Air Regulations and Mold
* Large Buildings and Mold
* Schools and Mold and Indoor Air Quality
* How to Order Publications

Introduction to Molds

Molds produce tiny spores to reproduce. Mold spores waft through the indoor and outdoor air continually. When mold spores land on a damp spot indoors, they may begin growing and digesting whatever they are growing on in order to survive. There are molds that can grow on wood, paper, carpet, and foods. When excessive moisture or water accumulates indoors, mold growth will often occur, particularly if the moisture problem remains undiscovered or un-addressed. There is no practical way to eliminate all mold and mold spores in the indoor environment; the way to control indoor mold growth is to control moisture.

* See also: An Introduction to Molds and Related Links

Basic Mold Cleanup

The key to mold control is moisture control. It is important to dry water damaged areas and items within 24-48 hours to prevent mold growth. If mold is a problem in your home, clean up the mold and get rid of the excess water or moisture. Fix leaky plumbing or other sources of water. Wash mold off hard surfaces with detergent and water, and dry completely. Absorbent materials (such as ceiling tiles & carpet) that become moldy may have to be replaced.

Ten Things You Should Know About Mold

1. Potential health effects and symptoms associated with mold exposures include allergic reactions, asthma, and other respiratory complaints.
2. There is no practical way to eliminate all mold and mold spores in the indoor environment; the way to control indoor mold growth is to control moisture.
3. If mold is a problem in your home or school, you must clean up the mold and eliminate sources of moisture.
4. Fix the source of the water problem or leak to prevent mold growth.
5. Reduce indoor humidity (to 30-60% ) to decrease mold growth by: venting bathrooms, dryers, and other moisture-generating sources to the outside; using air conditioners and de-humidifiers; increasing ventilation; and using exhaust fans whenever cooking, dishwashing, and cleaning.
6. Clean and dry any damp or wet building materials and furnishings within 24-48 hours to prevent mold growth.
7. Clean mold off hard surfaces with water and detergent, and dry completely. Absorbent materials such as ceiling tiles, that are moldy, may need to be replaced.
8. Prevent condensation: Reduce the potential for condensation on cold surfaces (i.e., windows, piping, exterior walls, roof, or floors) by adding insulation.
9. In areas where there is a perpetual moisture problem, do not install carpeting (i.e., by drinking fountains, by classroom sinks, or on concrete floors with leaks or frequent condensation).
10. Molds can be found almost anywhere; they can grow on virtually any substance, providing moisture is present. There are molds that can grow on wood, paper, carpet, and foods.

If you have IAQ and mold issues in your school, you should get a copy of the IAQ Tools for Schools Action Kit. Mold is covered in the IAQ Reference Guide under Appendix H – Mold and Moisture.

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Asthma and Mold

Molds can trigger asthma episodes in sensitive individuals with asthma. People with asthma should avoid contact with or exposure to molds.

EPA’s Asthma Website

Additional Resources:

* Allergy & Asthma Network/Mothers of Asthmatics (AAN/MA): (800) 878-4403 begin_of_the_skype_highlighting (800) 878-4403 end_of_the_skype_highlighting; www.aanma.org exiting EPA
* American Academy of Allergy, Asthma & Immunology (AAAAI): www.aaaai.org exiting EPA
* American Lung Association: 1-800-LUNG-USA begin_of_the_skype_highlighting 1-800-LUNG-USA end_of_the_skype_highlighting (1-800-586-4872 begin_of_the_skype_highlighting 1-800-586-4872 end_of_the_skype_highlighting); www.lungusa.org exiting EPA
* Asthma & Allergy Foundation of America: (800) 7ASTHMA begin_of_the_skype_highlighting (800) 7ASTHMA end_of_the_skype_highlighting; www.aafa.org exiting EPA
* Canada Mortgage & Housing Corporation “Fighting Mold – The Homeowner’s Guide” www.cmhc-schl.gc.ca/en/co/maho/yohoyohe/momo/momo_005.cfm exiting EPA
* National Institute of Allergy and Infectious Diseases: www.niaid.nih.gov
* National Jewish Medical and Research Center: (800) 222-LUNG begin_of_the_skype_highlighting (800) 222-LUNG end_of_the_skype_highlighting (5864); www.njc.org exiting EPA

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Floods/Flooding

Mold growth may be a problem after flooding. EPA’s Fact Sheet: Flood Cleanup: Avoiding Indoor Air Quality Problems – discusses steps to take when cleaning and repairing a home after flooding. Excess moisture in the home is cause for concern about indoor air quality primarily because it provides breeding conditions for microorganisms. This fact sheet provides tips to avoid creating indoor air quality problems during cleanup. U.S. EPA, EPA Document Number 402-F-93-005, August 1993.

Additional Resources:

* Federal Emergency Management Agency (FEMA): (800) 480-2520 begin_of_the_skype_highlighting (800) 480-2520 end_of_the_skype_highlighting; www.fema.gov Flood information – www.fema.gov/hazard/flood/index.shtm

* U.S. Department of Health and Human Services (HHS), Centers for Disease Control and Prevention’s (CDC) Emergency Preparedness and Response page on “Protect Yourself from Mold” – www.bt.cdc.gov/disasters/mold/protect.asp and Key Facts About Hurricane Recovery – www.bt.cdc.gov/hurricanes/index.asp

* University of Minnesota, Department of Environmental Health and Safety – www.dehs.umn.edu/iaq.htm exiting EPA Flood Information – www.dehs.umn.edu/iaq_fi.htm exiting EPA

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Health and Mold

How do molds affect people?

Some people are sensitive to molds. For these people, exposure to molds can cause symptoms such as nasal stuffiness, eye irritation, wheezing, or skin irritation. Some people, such as those with serious allergies to molds, may have more severe reactions. Severe reactions may occur among workers exposed to large amounts of molds in occupational settings, such as farmers working around moldy hay. Severe reactions may include fever and shortness of breath. Some people with chronic lung illnesses, such as obstructive lung disease, may develop mold infections in their lungs.

EPA’s publication, Indoor Air Pollution: An Introduction for Health Professionals, assists health professionals (especially the primary care physician) in diagnosis of patient symptoms that could be related to an indoor air pollution problem. It addresses the health problems that may be caused by contaminants encountered daily in the home and office. Organized according to pollutant or pollutant groups such as environmental tobacco smoke, VOCs, biological pollutants, and sick building syndrome, this booklet lists key signs and symptoms from exposure to these pollutants, provides a diagnostic checklist and quick reference summary, and includes suggestions for remedial action. Also includes references for information contained in each section. This booklet was developed by the American Lung Association, the American Medical Association, the U.S. Consumer Product Safety Commission, and the EPA. EPA Document Reference Number 402-R-94-007, 1994.

Allergic Reactions – excerpted from Indoor Air Pollution: An Introduction for Health Professionals section on: Animal Dander, Molds, Dust Mites, Other Biologicals.

“A major concern associated with exposure to biological pollutants is allergic reactions, which range from rhinitis, nasal congestion, conjunctival inflammation, and urticaria to asthma. Notable triggers for these diseases are allergens derived from house dust mites; other arthropods, including cockroaches; pets (cats, dogs, birds, rodents); molds; and protein-containing furnishings, including feathers, kapok, etc. In occupational settings, more unusual allergens (e.g., bacterial enzymes, algae) have caused asthma epidemics. Probably most proteins of non-human origin can cause asthma in a subset of any appropriately exposed population.”

Damp Buildings and Health

For information on damp buildings and health effects, see the 2004 Institute of Medicine Report, Damp Indoor Spaces and Health, published by The National Academies Press in Washington, DC. You can read a description of the report and purchase a copy at http://fermat.nap.edu/catalog/11011.html exiting EPA

The Center for Disease Control and Prevention (CDC’s) National Center for Environmental Health (NCEH) has a toll-free telephone number for information and FAXs, including a list of publications: NCEH Health Line 1-888-232-6789 begin_of_the_skype_highlighting 1-888-232-6789 end_of_the_skype_highlighting.

* CDC’s “Molds in the Environment” Factsheet – www.cdc.gov/mold/faqs.htm
* Stachybotrys or Stachybotrys atra (chartarum) and health effects – www.cdc.gov/mold/stachy.htm

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Homes and Molds

The EPA publication, “A Brief Guide to Mold, Moisture, and Your Home”, is available here in HTML and PDF formats in English (PDF, 20 pp, 257KB About PDF) and Spanish (PDF, 20 pp, 796KB About PDF). This Guide provides information and guidance for homeowners and renters on how to clean up residential mold problems and how to prevent mold growth.

Biological Pollutants in Your Home – This document explains indoor biological pollution, health effects of biological pollutants, and how to control their growth and buildup. One third to one half of all structures have damp conditions that may encourage development of pollutants such as molds and bacteria, which can cause allergic reactions — including asthma — and spread infectious diseases. Describes corrective measures for achieving moisture control and cleanliness. This brochure was prepared by the American Lung Association and the U.S. Consumer Product Safety Commission. The publication was updated by CPSC in 1997 www.cpsc.gov/cpscpub/pubs/425.html

Moisture control is the key to mold control, the Moisture Control Section from Biological Pollutants in Your Home follows:

Moisture Control

Water in your home can come from many sources. Water can enter your home by leaking or by seeping through basement floors. Showers or even cooking can add moisture to the air in your home. The amount of moisture that the air in your home can hold depends on the temperature of the air. As the temperature goes down, the air is able to hold less moisture. This is why, in cold weather, moisture condenses on cold surfaces (for example, drops of water form on the inside of a window). This moisture can encourage biological pollutants to grow.

There are many ways to control moisture in your home:

* Fix leaks and seepage. If water is entering the house from the outside, your options range from simple landscaping to extensive excavation and waterproofing. (The ground should slope away from the house.) Water in the basement can result from the lack of gutters or a water flow toward the house. Water leaks in pipes or around tubs and sinks can provide a place for biological pollutants to grow.
* Put a plastic cover over dirt in crawlspaces to prevent moisture from coming in from the ground. Be sure crawlspaces are well-ventilated.
* Use exhaust fans in bathrooms and kitchens to remove moisture to the outside (not into the attic). Vent your clothes dryer to the outside.
* Turn off certain appliances (such as humidifiers or kerosene heaters) if you notice moisture on windows and other surfaces.
* Use dehumidifiers and air conditioners, especially in hot, humid climates, to reduce moisture in the air, but be sure that the appliances themselves don’t become sources of biological pollutants.
* Raise the temperature of cold surfaces where moisture condenses. Use insulation or storm windows. (A storm window installed on the inside works better than one installed on the outside.) Open doors between rooms (especially doors to closets which may be colder than the rooms) to increase circulation. Circulation carries heat to the cold surfaces. Increase air circulation by using fans and by moving furniture from wall corners to promote air and heat circulation. Be sure that your house has a source of fresh air and can expel excessive moisture from the home.
* Pay special attention to carpet on concrete floors. Carpet can absorb moisture and serve as a place for biological pollutants to grow. Use area rugs which can be taken up and washed often. In certain climates, if carpet is to be installed over a concrete floor, it may be necessary to use a vapor barrier (plastic sheeting) over the concrete and cover that with sub-flooring (insulation covered with plywood) to prevent a moisture problem.
* Moisture problems and their solutions differ from one climate to another. The Northeast is cold and wet; the Southwest is hot and dry; the South is hot and wet; and the Western Mountain states are cold and dry. All of these regions can have moisture problems. For example, evaporative coolers used in the Southwest can encourage the growth of biological pollutants. In other hot regions, the use of air conditioners which cool the air too quickly may prevent the air conditioners from running long enough to remove excess moisture from the air. The types of construction and weatherization for the different climates can lead to different problems and solutions.

Moisture On Windows

Your humidistat is set too high if excessive moisture collects on windows and other cold surfaces. Excess humidity for a prolonged time can damage walls especially when outdoor air temperatures are very low. Excess moisture condenses on window glass because the glass is cold. Other sources of excess moisture besides overuse of a humidifier may be long showers, running water for other uses, boiling or steaming in cooking, plants, and drying clothes indoors. A tight, energy efficient house holds more moisture inside; you may need to run a kitchen or bath ventilating fan sometimes, or open a window briefly. Storm windows and caulking around windows keep the interior glass warmer and reduce condensation of moisture there.

Humidifiers are not recommended for use in buildings without proper vapor barriers because of potential damage from moisture buildup. Consult a building contractor to determine the adequacy of the vapor barrier in your house. Use a humidity indicator to measure the relative humidity in your house. The American Society of Heating and Air Conditioning Engineers (ASHRAE) recommends these maximum indoor humidity levels.

Outdoor Recommended Indoor Temperature Relative Humidity
+20o F. 35%
+10o F. 30%
0o F. 25%
-10o F. 20%
-20o F. 15%

Source: Anne Field, Extension Specialist, Emeritus, with reference from the Association for Home Appliance Manufacturers (www.aham.orgexiting EPA).

How to Identify the Cause of a Mold and Mildew Problem

Mold and mildew are commonly found on the exterior wall surfaces of corner rooms in heating climate locations. An exposed corner room is likely to be significantly colder than adjoining rooms, so that it has a higher relative humidity (RH) than other rooms at the same water vapor pressure. If mold and mildew growth are found in a corner room, then relative humidity next to the room surfaces is above 70%. However, is the RH above 70% at the surfaces because the room is too cold or because there is too much moisture present (high water vapor pressure)?

The amount of moisture in the room can be estimated by measuring both temperature and RH at the same location and at the same time. Suppose there are two cases. In the first case, assume that the RH is 30% and the temperature is 70oF in the middle of the room. The low RH at that temperature indicates that the water vapor pressure (or absolute humidity) is low. The high surface RH is probably due to room surfaces that are “too cold.” Temperature is the dominating factor, and control strategies should involve increasing the temperature at cold room surfaces.

In the second case, assume that the RH is 50% and the temperature is 70oF in the middle of the room. The higher RH at that temperature indicates that the water vapor pressure is high and there is a relatively large amount of moisture in the air. The high surface RH is probably due to air that is “too moist.” Humidity is the dominating factor, and control strategies should involve decreasing the moisture content of the indoor air.

Should You Have the Air Ducts in Your Home Cleaned? – excerpt on duct cleaning and mold follows, please review the entire document for additional information on duct cleaning and mold.

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.

Additional Resource

* U.S. Dept. of Agriculture, Food Safety and Inspection Service fact sheet – Safe Food Handling- Molds on Foods: Are They Dangerous? www.fsis.usda.gov/FactSheets/Molds_On_Food/index.asp September 2005

* A Brief Guide to Mold in the Workplace, U.S. Dept. of Labor, Occupational, Safety and Health Administration, Safety and Health Bulletin 03-10-10

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Indoor Air Regulations and Mold

Standards or Threshold Limit Values (TLVs) for airborne concentrations of mold, or mold spores, have not been set. Currently, there are no EPA regulations or standards for airborne mold contaminants.

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Large Buildings and Mold

EPA has a number of resources available, you can start with the Indoor Air Quality Building Evaluation and Assessment Model (I-BEAM). I-BEAM updates and expands EPA’s existing Building Air Quality guidance and is designed to be comprehensive state-of-the-art guidance for managing IAQ in commercial buildings. This guidance was designed to be used by building professionals and others interested in indoor air quality in commercial buildings. I-BEAM contains text, animation/visual, and interactive/calculation components that can be used to perform a number of diverse tasks. See www.epa.gov/iaq/largebldgs/i-beam/index.html

See also “Building Air Quality: A Guide for Building Owners and Facility Managers”.

Excerpt from the Building Air Quality: A Guide for Building Owners and Facility Managers, Appendix C – Moisture, Mold and Mildew:

How to Identify the Cause of a Mold and Mildew Problem.

Mold and mildew are commonly found on the exterior wall surfaces of corner rooms in heating climate locations. An exposed corner room is likely to be significantly colder than adjoining rooms, so that it has a higher relative humidity (RH) than other rooms at the same water vapor pressure. If mold and mildew growth are found in a corner room, then relative humidity next to the room surfaces is above 70%. However, is the RH above 70% at the surfaces because the room is too cold or because there is too much moisture present (high water vapor pressure)?

The amount of moisture in the room can be estimated by measuring both temperature and RH at the same location and at the same time. Suppose there are two cases. In the first case, assume that the RH is 30% and the temperature is 70oF in the middle of the room. The low RH at that temperature indicates that the water vapor pressure (or absolute humidity) is low. The high surface RH is probably due to room surfaces that are “too cold.” Temperature is the dominating factor, and control strategies should involve increasing the temperature at cold room surfaces.

In the second case, assume that the RH is 50% and the temperature is 70oF in the middle of the room. The higher RH at that temperature indicates that the water vapor pressure is high and there is a relatively large amount of moisture in the air. The high surface RH is probably due to air that is “too moist.” Humidity is the dominating factor, and control strategies should involve decreasing the moisture content of the indoor air.

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Schools and Mold and Indoor Air Quality

The Agency’s premier resource on this issue is the Indoor Air Quality Tools for Schools kit. Our schools-related resources on the web start at: www.epa.gov/iaq/schools.

The asthma companion piece for the IAQ Tools for Schools Action kit, is Managing Asthma in the School Environment – www.epa.gov/iaq/schools/managingasthma.html. This publication has a section entitled Clean Up Mold and Moisture Control: An excerpt follows:

Common Moisture Sources Found in Schools

Moisture problems in school buildings can be caused by a variety of conditions, including roof and plumbing leaks, condensation, and excess humidity. Some moisture problems in schools have been linked to changes in building construction practices during the past twenty to thirty years. These changes have resulted in more tightly sealed buildings that may not allow moisture to escape easily. Moisture problems in schools are also associated with delayed maintenance or insufficient maintenance, due to budget and other constraints. Temporary structures in schools, such as trailers and portable classrooms, have frequently been associated with moisture and mold problems.

Suggestions for Reducing Mold Growth in Schools

Reduce Indoor Humidity

* Vent showers and other moisture-generating sources to the outside.
* Control humidity levels and dampness by using air conditioners and de-humidifiers.
* Provide adequate ventilation to maintain indoor humidity levels between 30-60%.
* Use exhaust fans whenever cooking, dishwashing, and cleaning in food service areas.

Inspect the building for signs of mold, moisture, leaks, or spills

* Check for moldy odors.
* Look for water stains or discoloration on the ceiling, walls, floors, and window sills.
* Look around and under sinks for standing water, water stains, or mold.
* Inspect bathrooms for standing water, water stains, or mold.
* Do not let water stand in air conditioning or refrigerator drip pans.

Respond promptly when you see signs of moisture and/or mold, or when leaks or spills occur

* Clean and dry any damp or wet building materials and furnishings within 24-48 hours of occurrence to prevent mold growth.
* Fix the source of the water problem or leak to prevent mold growth.
* Clean mold off hard surfaces with water and detergent, and dry completely.
* Absorbent materials such as ceiling tiles, that are moldy, may need to be replaced.
* Check the mechanical room and roof for unsanitary conditions, leaks, or spills.

Prevent moisture condensation

* Reduce the potential for condensation on cold surfaces (i.e., windows, piping, exterior walls, roof, or floors) by adding insulation.

Floor and carpet cleaning

* Remove spots and stains immediately, using the flooring manufacturer’s recommended techniques.
* Use care to prevent excess moisture or cleaning residue accumulation and ensure that cleaned areas are dried quickly.
* In areas where there is a perpetual moisture problem, do not install carpeting (i.e., by drinking fountains, by classroom sinks, or on concrete floors with leaks or frequent condensation).

How to Order Publications

You can order Indoor Air Quality publications from EPA’s National Service Center for Environmental Publications (NSCEP):

U.S. Environmental Protection Agency
National Service Center for Environmental Publications (NSCEP)
P.O. Box 42419
Cincinnati, OH 45242-0419
Website: www.epa.gov/nscep
Fax: (301) 604-3408
E-mail: nscep@bps-lmit.com

NSCEP operates a Toll-free phone service for EPA Publication Assistance with live customer service representative assistance Monday through Friday from 9:00am-5:30pm eastern time. Voice Mail is available after operating hours. You can fax or e-mail your publication requests. For technical assistance with NSCEP web pages, write to: nscep_nepis.tech@epa.gov

Please use the EPA Document Number, which is usually bolded or highlighted, when ordering from NSCEP.