• Word on the Street
• Industry Tells Congressional Committee: Support HVAC Upgrades
• Is It Appropriate for the Same Person to Collect and Analyze Samples?
• New Evidence on the Health Effects of Poor Indoor Air
• To Have or Have Not Radon-Related Codes
• A Possible Link Between Depression and Water Damage
• How to Control Contamination During Health Care Facility Construction

HOUSING DOWNTURN CLAIMS ANOTHER VICTIM

American Mold Guard Inc. announced April 2 that as of April 7, it would formally cease conducting all operations and permanently terminate its business of providing decontamination and protective coating products and services. In connection with the termination of all of its operations, the company has closed all of its offices and has laid-off all remaining employees.

Mark Davidson, chief executive officer of American Mold Guard, said, “We are saddened and disappointed by the sudden discontinuation of American Mold Guard’s business operations. We and our employees worked extremely hard to avoid where we are today.”

“Unfortunately, the severe and unprecedented decline in the residential new construction market, combined with our inability to raise capital sufficient enough to effectuate a planned business strategy of making us less dependent on the residential new construction market for our revenues and cash flows, proved to be business conditions that we could not overcome.”

Prior to termination of its business operations, American Mold Guard had engaged in extensive discussions with a number of parties in an effort to obtain capital or identify opportunities that would have allowed it to continue operations.

However, despite its efforts, American Mold Guard could not continue operations.

NEW LEAD-BASED PAINT RULES

To further protect children from exposure to lead-based paint, EPA is issuing new rules for contractors who renovate or repair housing, child-care facilities or schools built before 1978.

Under the new rules, workers must follow lead-safe work practice standards to reduce potential exposure to dangerous levels of lead during renovation and repair activities.

“While there has been a dramatic decrease over the last two decades in the number of children affected by lead-poisoning, EPA is continuing its efforts to take on this preventable disease,” said James Gulliford, EPA’s Assistant Administrator for Prevention, Pesticides and Toxic Substances.

“Today’s new rules will require contractors to be trained and to follow simple but effective lead-safe work practices to protect children from dangerous levels of lead.”

The “Lead: Renovation, Repair and Painting Program” rule, which will take effect in April 2010, prohibits work practices creating lead hazards. Requirements under the rule include implementing lead-safe work practices and certification and training for paid contractors and maintenance professionals working in pre-1978 housing, child-care facilities and schools.

To foster adoption of the new measures, EPA will also conduct an extensive education and outreach campaign to promote awareness of these new requirements. The rule covers all rental housing and non-rental homes where children under six and pregnant mothers reside.

The new requirements apply to renovation, repair or painting activities where more than six square feet of lead-based paint is disturbed in a room or where 20 square feet of leadbased paint is disturbed on the exterior. The affected contractors include builders, painters, plumbers and electricians.

INDOOR ISSUES AT INTERIOR

The main building of the U.S. Department of the Interior is filled with dust and fumes and is making employees there sick, the Washington Post reported.

According to a survey by the Interior Department’s inspector general, 28 percent of respondents from the headquarters building “stated that serious health and safety deficiencies exist in their workplace.”

The report said “this high percentage” was probably caused by the modernization project, a multimillion-dollar upgrade of heating, air conditioning, plumbing and wiring in the building that is scheduled to be completed in 2012.

Departmental officials have tried to reassure the 1,700 employees at the building that they are monitoring the renovation.

Evaluations of health hazards were conducted in 2006 and 2007, and they produced recommendations to improve indoor air quality and address environmental problems.

Shane Wolfe, the department’s press secretary, said barriers have been installed to minimize dust from construction areas, and an industrial hygienist is monitoring air quality in the building.

Employees cited dirty air filters, inadequate building ventilation and falling brick dust in deteriorating buildings, the report said. Many respondents said they were concerned about mold, radon and asbestos. Others were concerned about being continuously exposed to rodent and insect infestations, the report said.

by Tom Scarlett

Going "green" with new HVACR equipment can have a positive impact on the bottom line for home owners, small businesses, and the overall economy, a representative of the Air Conditioning Contractors of America (ACCA) told a congressional panel recently,

Ellis Guiles of TAG Mechanical in Syracuse, New York, testified before the House Small Business Committee on behalf of ACCA, the nationwide association of heating, ventilation, air conditioning, and refrigeration (HVACR) contractors.  The hearing was on "The Role of Green Technologies in Spurring Economic Growth".

Guiles' testimony focused on the expanding demand for innovative, higher efficiency HVACR equipment that lowers utility and maintenance costs, improves indoor air quality, and reduces greenhouse gas emissions.

"Increased efficiency is the low hanging fruit in the effort to reduce energy consumption, promote national security, and stimulate the national economy," said Guiles.

Chairwoman Nydia Velazquez (D-N.Y.) and Ranking Republican Steve Chabot (R-Ohio) have held a series of hearings on the role small businesses in emerging technologies, including energy efficiency and renewable energy.

Panelists at this hearing also included representatives from the National Electrical Contractors Association (NECA), the American Wind Energy Association (AWEA), the Solar Energy Industries Association (SEIA), the National Association of Home Builders (NAHB), and the Plumbing-Heating-Cooling-Contractors Association (PHCC).

Panelists Urge Tax Incentive

Each panelist stressed the importance of Congress passing a $50 billion tax package that renews critical tax incentives for home owners and building owners that invest in highly efficient technologies, including HVACR equipment.

"Cost is the greatest hurdle to these technologies for homeowners and small businesses," said Guiles. "The higher efficiency products cost more in upfront, due to higher component costs, installation requirements. However, the initial investment on a high efficiency appliance earns a shorter payback period with lower life cycle costs."

ACCA has urged Congress to extend and expand current and expired tax incentives for making high efficiency improvements to home and commercial buildings. These include the $500 tax credit for homeowners who install qualified high efficiency furnaces, air conditioners, heat pumps, and hot water heaters; and a $1.80 per square foot tax deduction to building owners who make a 30% improvement to overall building energy use.

In response to questions about the tax credits, Guiles said that consumers took advantage of the tax credits. "We found that 90% of the residential consumers would choose to go with the higher efficiency equipment because the tax credit allowed them to offset the higher costs. The consumer said if I can get the tax credit, why wouldn't I do this? Unfortunately those tax credits lapsed last year."

Highlighting that Guiles pointed out that "realizing a 15-20% reduction in energy consumed by residential and commercial buildings, using available technology, is not unreasonable. This would result in $28 billion in saved energy expenditures while creating a tremendous number of jobs within the HVACR industry as demand for more efficient equipment and its installation grows."

“The potential for America’s small businesses and the HVACR contractors that service those small businesses, for job creation, economic growth, and environmental protection are limitless,” Guiles said. “However, in order to turn this potential into reality, Congress needs to provide direction and assistance through tax incentives, increased public awareness, proper installation and maintenance, and code enforcement.”

Increased efficiency “is the low hanging fruit in the effort to reduce energy consumption, promote national security, and stimulate the economy,” he continued. According to the Department of Energy’s 2005 Buildings Energy Databook and the Energy Information Administration, residential buildings account for 22% of all US energy consumption. Of that, 30.7% goes toward space heating and 12.3% goes toward space cooling, with another 12.2% going toward water heating. Commercial buildings account another 18% of total US energy consumption.

Within those buildings, 14.2% of the energy consumed goes toward space heating, 13.1% goes toward space cooling, and 6% goes toward ventilation.
All told, nearly $142 billion was spent nationally in 2005 on space heating and cooling for both residential and commercial buildings combined.

According to the 2005 Residential Energy Consumption Survey, 39% of the residential central air conditioners and 60% of residential heating equipment were more than 10 years old. Since 1990, only 30% of commercial buildings have had their main heating equipment replaced, and only 37% have had their main cooling equipment replaced.

“Realizing a 15-20% reduction in energy consumed by residential and commercial buildings, using available technology, is not unreasonable,” the ACCA representative said. “This would result in $28 billion in saved energy expenditures while creating a tremendous number of jobs within the HVACR industry as demand for more efficient equipment and its installation occurs. There would also be an increase in tax revenues due to increased jobs and sales/installation of equipment providing a funding mechanism to allow for a balanced approach (tax revenues offsetting tax incentives) to funding tax incentives for individuals and businesses who want to take advantage of technologies available today.”

Guiles' full written testimony can be read at www.acca.org/testimony/.

I think that having the same person collect and analyze samples introduces both bias and conflict of interest into investigations, neither of which is helpful for the client or the investigator, especially if the issue ultimately winds up in the legal system.

Bias occurs when an investigator wants or expects to find a specific result, either positive or negative. For example, if you see black mold on a wall and you think it is Stachybotrys, then you expect to find Stachybotrys on air samples.

The tendency is, then to collect lots of samples (because you have heard that Stachybotrys doesn’t easily become airborne), and/or to search the samples especially diligently for Stachybotrys. Collecting tape samples of obvious black growth and then interpreting the high numbers of spores on the tape to mean serious contamination is a form of bias that is made even worse if the person doing the sampling is the same one who counts the spores.

There is also the possibility of ignoring other things that could be on the wall and in the air. Sampling bias occurred in the Centers for Disease Control investigations of the hemosiderosis outbreak in Cleveland. The investigators collected many more samples in their case buildings than in the control buildings, making any real comparison between the two impossible.

Controlling sampling bias can be done using hypothesis-driven investigations in which you design the sampling protocol to try to disprove your hypothesis. In the CDC case, the investigators should have taken as many or more samples in the control houses to be absolutely sure that they were not missing any possible Stachybotrys spores. Controlling analytical bias is easy: send your samples to a third party lab for analysis.

Conflict of interest arises when the person doing the sampling charges for both sampling and analysis. In such a situation, there is the temptation to collect more samples than necessary because the resulting income will be higher.

I know you will say that you would never do that. However, even the appearance of conflict of interest can be detrimental if the case winds up being litigated.

I have not collected samples since I began working for EMLab P&K, a company whose business it is to analyze samples. I don’t think bias would be involved if I were to collect the samples because I am not in direct contact with the analysts, but conflict of interest would certainly be an issue. Also, our policy is not to collect samples, because we would then be in direct competition with our clients.

Finally, no one can be an expert in all areas. Being a great home or building investigator is challenging enough without taking on the task of being a good mycologist/microbiologist and analyzing samples under the supervision of a professional quality control specialist. Likewise, remediation should be done by people who specialize in plumbing, electrical work, dry wall installation, carpentry, etc. None of these trades learn to develop sampling strategies, nor do they know how to analyze field samples. Let’s leave each of these specialties (investigations, analysis, remediation) to the experts!

Study Finds Link between Indoor Air Pollution and Heart Disease

by Tom Scarlett

      A recent study that concluded poor indoor air quality adversely affects the performance of blood vessels in humans is only the most recent of several studies finding a link between indoor air pollution and cardiovascular disease – the number one killer in America.

      The latest study, conducted by a team of scientists from Denmark and Sweden, found that tiny particles of indoor air pollution that are inhaled and get into the bloodstream affect the performance of blood vessels, and potentially increase the risk of cardiovascular disease, particularly among the elderly. The study was published in the American Journal of Respiratory and Critical Care Medicine.

      The scientists investigated the effect of air particles on three indicators of blood vessel health on 21 nonsmoking elderly couples, studied in their homes. The study also found that when the air quality was improved using filters, the subjects' blood vessels functioned better.

      Physicians and scientists have known for years that exposure to air pollutants – such as the microscopic particles emitted in various types of vehicle, industrial and power plant exhaust fumes – increased risk factors for cardiovascular disease. This is because the endothelial cells that line the walls of all blood vessels become damaged by the tiny particles once they get into the bloodstream. The new study is the first major project to extend this inquiry to indoor air quality.

"Reduction of particle exposure by filtration of re-circulated air for only 48 hours improved the microvascular function (MVF) in healthy citizens," said Professor Steffen Loft, M.D., of the Institute of Public Health in Copenhagen, who led the team that conducted the study. "This suggests that indoor air filtration represents a feasible means of reducing cardiovascular risk."

The researchers found that HEPA filtration removed about 60 percent of the ultrafine, fine and coarse air particles in homes, and was associated with an 8.1 percent improvement in individual MVF.

"We expected that removing air particles with the HEPA filters would result in improvement of MVF but we were heartened and surprised by the extent it did, considering the modest levels of particles in the indoor air of the homes of the elderly," said Loft.

The researchers investigated the effect of air particles on three benchmarks of blood vessel health: microvascular function, oxidative stress, and inflammation. They recruited a total of 21 non-smoking elderly couples, aged between 60 and 75, to take part in a randomized, double blind, crossover study of two exposure episodes lasting 48 hours each, both in their homes.

This meant the couples were randomly selected to be exposed either to filtered air first and then to non-filtered air, or the other way around. All the couples were in good health and lived near busy roads. The exposure was controlled by putting air purifiers in their homes, with and without an air filter fitted inside.

The results showed that:

·         Filtered air significantly improved MVF by 8.1 per cent.

·         The diameter of the air particles (smaller than 2.5 micrometers) and their mass, had a greater effect than their total number concentration.

·         MVF was also significantly linked to being exposed to particles containing iron, potassium, copper, zinc, arsenic, and lead.

·         After applying a test of statistical significance, none of the other biomarkers (oxidative stress and inflammation) varied significantly with particle exposure.

The researchers concluded that: “Reduction of particle exposure by filtration of recirculated indoor air for only 48 hours improved MVF in healthy elderly citizens, suggesting that this may be a feasible way of reducing the risk of cardiovascular disease.

Endothelial cells line the walls of all blood vessels throughout the body from the smallest capillary to the largest artery. They are involved in lots of important jobs from controlling blood flow, reducing clotting, keeping arteries clear, reducing swelling and forming new blood vessels. They also control the movement of blood materials like white blood cells into and out of the bloodstream, and in some organs like the kidneys and the brain; they act as a blood filter.

Endothelial dysfunction therefore affects all these aspects of the cardiovascular system, and often results in atherosclerosis, where arteries get clogged up with plaques and then swell (and sometimes burst) with the resulting inflammation. This also narrows the arteries and stops the blood getting to the organ concerned, for instance

as in a heart attack.”

Reaction

      Carl Grimes of Healthy Habitats believes that “we need more interface between the medical community and the IAQ world on the specific health effects of indoor air quality.” As more studies of this kind emerge, the focus will increasingly shift away from pure measurements to environmental health concerns, he said.

      Grimes noted that several recent studies have found a link between ozone concentrations and cholesterol levels, as well as research showing a connection between endotoxins and diesel particulates.

            Asked whether the new evidence linking IAQ and heart disease would lead to more research funding on indoor air issues, Grimes said, “I certainly hope so.”

Other Studies of Health Effects

      The Denmark-Sweden study is only the latest to find a link between indoor air quality and cardiovascular health. A 2006 study showed how ozone's byproducts in the body can harden arteries and cause heart disease. Chemist Paul Wentworth, Jr., of the Scripps Research Institute and his colleagues tested such byproducts--known as atheronals--in vitro. These molecules form when ozone and cholesterol interact. "Cholesterol makes up 40 percent of most of your membranes, including those in your lungs," Wentworth explained. "If you inspire smog, there directly is the interaction."

The team's previous research had shown that the white blood cells responsible for inflaming arterial walls also produce ozone and, ultimately, the atheronals: atheronal-a and atheronal-b. These compounds are present in the plaque removed from clogged arteries. The new research shows that when the atheronals interact with various blood cells, they produce some of the effects known to lead to heart disease, such as causing a malfunction in the cells that line arterial walls. "The atheronals can actually cause all the relative aspects that are known to promote cardiovascular disease," Wentworth noted.

      Additionally, a 2007 study found a link between fine particulate air pollution and mortality in several California counties.

      Several epidemiologic studies had provided evidence of an association between mortality and particulate matter of relatively large diameter (PM2.5). The researchers found “a definite connection” between increases in particulate matter in the atmosphere and multiple mortality categories, “especially cardiovascular deaths.” Stronger associations were observed between mortality and additional pollutants, including sulfates and several metals, during the cool season.

In February I had the opportunity to attend an educational conference sponsored by a local chapter of the International Code Council, a meeting that was attended by over 1,800 building officials and inspectors from jurisdictions all over the country. Linda Bartisch of the Colorado Department of Public Health and Environment and I had an opportunity to discuss the pros and cons of adopting building codes relating to radon-resistant new home construction.

The purpose of our having an exhibition

booth at the conference was to focus specifically on the elements of Appendix F of the 2003 and 2006 International Residential Code, which details methods for installing passive radon control systems in homes being constructed in high radon potential areas. Although many jurisdictions in the country have adopted these revised versions of the code, they may or may not have adopted Appendix F, which is, as the name suggests, an Appendix rather than an element within the body of the code.

Having been at this same conference last year, we noted a higher frequency of representatives from jurisdictions around the country indicating they either had adopted Appendix For were considering doing so. Unfortunately, this was not true of most comments, with many statements made along the lines of “We really didn’t consider it during the last code adoption process.” After hearing this several times, I began to wonder what the liability implications of this might be.

What Are The Responsibilities

for Adopting Radon-Related

Building Codes?

First, let’s explore what Appendix F is. It’s a prescriptive code that details installation techniques for the installation of passive radon control systems in new homes. They are passive in that they consist of a means of collecting radon-laden soil gas from beneath a foundation and providing a pathway (pipe) to where they can find their way into the atmosphere above the roof, without the aid of a mechanical fan.

If the new occupant of the home tests and determines that radon levels are higher than they would prefer, a mechanical fan can easily be installed to reduce the indoor radon levels as provisions are made during the construction to allow for this.

This summary is probably no surprise to those who read this monthly column. The benefits of doing so – such as aesthetics, cost-effectiveness and health risk reductions – would also not be a surprise. However, in considering the elements of Appendix F, it occurred to me that there may be an additional element to consider, which is the liability connected with consciously not adopting this Appendix.

It is up to the local code official or his/her governing body to adopt or not adopt Appendix F. To aid the local building department in determining if such an adoption is warranted, Appendix F clearly lists all of the counties that are felt to have a high potential for elevated radon, where adoption of the appendix would be recommended. In addition to the listing of counties, there is also a map showing the same information visually. The scope of the Appendix reads as follows:

“Inclusion of this appendix by jurisdictions shall be determined through the use of locally available data or determination of Zone 1 designation in Figure AF101. (AF101 is the Zone

map cited above).

With such clear indications of relevance, it presumably would be diffi cult for a building official familiar with the code and also located within a Zone 1 area to ignore consideration of Appendix F. However, during the conference we heard many comments from building department representatives who said that no discussion of this appendix occurred during the last code review cycle, even though they were ndeed located within a Zone 1 area.

A number of years ago, one could argue that omission of this appendix could be excusable due to a general lack of awareness of the issue.

However, with the increasing number of stories about radon in the media, it is becoming harder and harder to deny awareness of the clear and present risk that radon can present, especially in those areas identified as high potential areas within Appendix F.

Sovereign Immunity or Doing the Right Thing?

However, after discussing this potential liability with two respected attorneys, I was reminded that sovereign immunity is alive and well in many governmental agencies. I was also reminded that linking a case of lung cancer to radon exposure and then further establishing that exposure would have been prevented by adoption of a prescriptive building code standard would be difficult.

So, perhaps sovereign immunity may shield a jurisdiction from their conscious decision not to adopt this appendix. But it still is not a reason for a building offi cial or an elected official not to perform their duty of protecting the public from known dangers. If not for liability protection, then how about doing it because it is the right thing to do?

Hopefully, things are turning around. The increased number of positive comments was encouraging; but even more encouraging was the number of building officials asking for coupons to allow them to test their own homes. Perhaps, the consciousness or outrage over not having had this issue dealt with during construction will start at home – their homes!

As always who says there is nothing new in radon?

Cassidy Kuchenbecker
Project Scientist
Michaels Engineering
La Crosse, WI 

In the summer of 2007, Brown University issued a study headed by epidemiologist Edmond Shenassa, Ph.D. that found a statistical link between depressive symptoms and indoor fungal growth (mold) and dampness.  The study was later published in the October 2007 edition of the American Journal of Public Health.   Reportedly, it was the first such statistical study focusing on this potential association. 

The study generated numerous headlines and rippled through the general and indoor air quality (IAQ) communities.  Many IAQ practitioners and restoration contractors hail this study as a positive step toward increased public awareness of the adverse health effects from exposure to damp indoor spaces.  However, like many studies, it is not without its critics. 

The study concluded that contaminants released from water-damaged building materials may induce depressive symptoms.  This conclusion, of course, takes into account plausible confounders and mediators.  Findings by the Brown team may seem like a shocking revelation to many.  However, several immunology, physiology, and physician researchers have been producing evidence for over a decade that, when taken together, provides probable mechanisms behind the induced depressive symptoms.      

The Brown study retrospectively assessed data from the Large Analysis and Review of European Housing and Health Status (LARES) project that was completed in 2002-2003 in eight European cities by the World Health Organization (WHO).  Trained interviewers assessed the condition of homes and surrounding environments, and the occupants completed self-reported health and indoor mold/dampness questionnaires.    Data from the LARES project has been used in several past, non-related statistical studies by other research groups. 

Four symptoms of depression were indexed in this study: sleep disturbances, decreased interest in activities, low self-esteem, and decreased appetite during the two weeks prior to the interview.  Occupants with three or four of the symptoms were classified as depressed.  This classification was based on other published studies of major depression.  A secondary criterion included whether a physician made the diagnosis of anxiety or depression during the twelve months preceding the interview.  Indexing of data on indoor mold/dampness was from reports by both the interviewer and the occupants, whose data correlated fairly well.  In total 5,882 individuals from 2,982 residences were used in this particular statistical analysis.  While some stones have been cast concerning study design issues, overall it was a solid start to what will hopefully be a series of studies by this group and others.   

The purpose of this article is not to dissect the study, but instead to look at the possible mechanisms between damp spaces and depression.  For the remainder of this article, the term water-damaged buildings (WDBs) will be used to describe both damp spaces and those that experienced bulk water damage. 

So what is the connection between depression and WDBs?  The authors of the Brown study indicate a statistical association between depression and the perceived lack of control over one's environment may partially mediate the association between dampness and depression.  A stronger mediator found in this study was an association between chronic respiratory distress and depression, which can be induced by contaminants released in WDBs.  In other words, people who have chronic respiratory distress may feel depressed because of their ailments. 

However, even with the additive effect of these two mediators, not all of the association between WDBs and depression was accounted for.  The authors indicate that this finding "suggests the possibility of a direct pathological effect of mold exposure."  This is a bold statement, one that is sure to stir controversy among researchers and practitioners alike.

Many readers of this article have likely formed one of the following opinions:  1) Mold doesn't cause health effects beyond respiratory ailments and allergies.  The National Institutes of Health committee that developed the 1994 publication, "Damp Indoor Spaces and Health" didn't find any additional significant associations.  Or, 2) It’s an effect of the mold toxins, of course.   However, experimental and observational evidence do not fully support either of these paradigms.

More than a decade before the Brown University study, in vivo and in vitro evidence was published that strongly suggested many depressive symptoms are the result of chronic activation of the immune system ("chronic inflammation").  That's right: Those little white blood cells that have diligently kept you alive can also affect your mood.  Research is also showing that obesity and uncontrolled weight gain can be a byproduct of chronic inflammation.  Ever ask a client if they have been depressed or recently gained weight following a water-damage event?  After you get past the uncomfortable, momentary silence, you may be surprised by what you hear. 

In the 1990s, research began to correlate depression with elevated levels of pro-inflammatory cytokines.  Cytokines are proteins released primarily by immune cells and adipose tissue that regulate the actions of other immune cells.  There are both pro-inflammatory and anti-inflammatory cytokines.  For the remainder of this article, the term cytokines will only refer to those that induce inflammation. 

At first, researchers were uncertain if elevated levels of cytokines (and thus chronic inflammation) were the cause or result of depression.  Subsequent studies showed that cytokine levels significantly decreased when patients began taking certain classes of antidepressants.  Specifically, patients taking drugs in the classes of selective serotonin reuptake inhibitors (i.e., Zoloft and Paxil) and tricyclic antidepressants (i.e., Tofranil and Anafranil) were shown to have significantly decreased levels of two important pro-inflammatory cytokines following treatment.  When immune cells in the lab were exposed to these antidepressants, their cytokine production was slowed and, in some cases, ceased! 

Where does that leave us?  It can be said with reasonable confidence that elevated levels of cytokines are the likely cause of some forms of depression.  It is generally believed that the cytokines either directly affect portions of the brain, or indirectly cause depression by their documented disruption of many processes of the hypothalamus-pituitary-adrenal system.

To recap, I just stated that depressive symptoms are statistically correlated with exposure to WDBs.  Next, I noted that many forms of depression are the result of chronic inflammation.  Can you guess where I’m going next?  That's right, evidence shows that chronic inflammation, which causes depression, can be induced by exposure to WDBs. 

Recently published studies measuring blood markers provide evidence that exposure to WDBs results in chronic activation of the immune cells (and possibly the adipose tissue) and release of cytokines in genetically susceptible people.  To shorten that sentence: exposure to WDBs results in chronic inflammation in susceptible people.  Multiple chemicals and biological agents that are released from water-damaged building materials act as inflammagens - agents that cause inflammation.  As a side note, this is the reason why it is incorrect to only consider fungal growth when dealing with water damage.   Multiple immune pathways to inflammation are activated when exposed to the mixed levels of these agents.   Most notably, the innate immune system can go rampant. 

The innate immune system is found in very primitive vertebrates, suggesting it was one of the earliest immune mechanisms to develop.  Cells of the innate immune system are the first on scene to fight infections and other foreign invaders.  

One well-documented innate reaction is the binding of lipopolysaccharide (LPS), found on the membranes of Gram-negative bacteria, to receptors on the innate immune cells and adipose cells.  The binding of LPS to the cell receptors triggers the cell to go into “attack mode”, resulting in an immediate inflammatory reaction.  While it has yet to be proven, some researchers hypothesize that other biological and chemical agents may bind in a comparable to similar, but yet unidentified, receptors. 

Besides the innate immune system, another prominent inflammatory pathway being considered is the over-activation of T-helper 1 (Th1) cells, which causes delayed-type hypersensitivity (DTH).  A DTH reaction is similar to classical allergies, except that it requires a day or two to develop.  Allergists can screen for DTH reactivity by providing the typical scratch test used for immediate reactions, but then also recording the swelling reaction ("wheal and flare") two days following the visit.  Practitioners at Allergy Associates of La Crosse have observed unexplainable decreases in symptoms associated with chronic inflammation and the successful desensitization of the DTH reaction following immunotherapy.  The significance of DTH reactions in WDB exposures is still poorly understood as few studies have been completed.

 T-cells are the "masterminds" of the cellular (vs. innate) immune system.  These are the cells that tell all the other cells what to do.  T-helper cells orchestrate antibody production by other immune cells.  HIV (which leads to AIDS) attacks and kills T-helper cells, leading to immunodeficiency.  T-helper 2 (Th2) cells generally lead to production of the IgE antibody class.  IgE antibodies trigger immediate allergic responses.  T-helper 1 (Th1) cells generally lead to IgG antibody production.  Typically, IgG antibodies are the primary weapons made against bacterial infections. 

As a side note, the "hygiene hypothesis" basically suggests that a lack of exposure to bacteria (evoking Th1 and IgG responses) while young allows a shift to Th2, resulting in more IgE and more allergies.  Although reasons are not clearly defined, the Th1 cells are sometimes over-activated.  Instead of eliciting the normal production of IgG, they release cytokines that result in an influx of other immune cells.  The incoming immune cells further stimulate the Th1 cells, resulting in a snowball effect.  This snowball effect results in the copious release of cytokines that, hypothetically, may result in depressive symptoms.  

Still others support hypotheses that chemoreceptors, which directly and quickly activate immune processes, may be bound by these agents, resulting in chronic inflammation.  Such pathways are currently being strongly considered in the development of multiple chemical sensitivities (MCS).

If a person is susceptible to inflammation induced by exposure to WDBs, he or she can blame genetic make-up.  In the case of activation of the innate immune system, it appears that some people are not able to clear the inflammagens from their system.  Very convincing published studies provide strong evidence showing that the use of chelators, most notably cholestyramine, is able to bind these inflammagens, removing them from the system.  Actually, it was this accidental observation that led to the numerous works by the Shoemaker and Hudnell group. 

Two lines of reasoning have been put forth to explain the lack of ability to naturally remove inflammagens.  The first line of thought indicates that susceptible people do not have the genetic capacity to produce antibodies to clear the inflammagens from the system.  Antibodies are proteins that are produced by immune cells that "stick" to very specific targets.  For example, if a person has an infection with the bacteria Staphylococcus aureus  ("Staph infection"), then the immune cells make antibodies that seek out and destroy this bacterium, while bypassing other bacteria. 

Another line of thought points to genetic statistical studies that indicate people sensitive to certain classes of chemicals have mutations in specific genes that produce liver enzymes.  It is thought that these mutated enzymes are unable to break down and clear certain chemical and biological agents when they pass through the liver.  The majority of evidence supporting this hypothesis deals with genetic mutations involved with autoimmune diseases - another group of inflammatory-related diseases. 

To the knowledge of this author, studies correlating depression and liver enzyme mutations have not been completed. 

A third potential answer lies with another T-cell line called the T-regulatory (Treg) cells.   Treg cells are nearly identical to Th1 and Th2 cells, except they tell the immune system to shut down instead of activate.  Dysfunction in Treg cells is being blamed for everything from allergies and autoimmune diseases to psychiatric diseases.  The evidence published in the last several years implicating these cells in disease is tremendous. 

Some consider Treg cells to be THE hot topic in immunology.  Evidence shows we all have Th1 and Th2 cells in our bodies that are trying to react against nearly everything we ingest and inhale.  In fact, we even have T-helper cells all over our bodies that are trying to attack our own cells.  It is the actions of Treg cells that keep these undesirable antibody productions from occurring.  When a person undergoes allergy or DTH immunotherapy through shots or sublingual drops, they are actually stimulating the growth of the Treg populations.  It is now a certainty that Treg cells prevent your immune system from attacking "normal" substances like food proteins and even your own proteins.  A lack of Treg function is at the core of most autoimmune diseases.  When Treg cells are removed from animal models, they quickly develop a number of autoimmune diseases. 

What about the "toxic" effect of mold exposure that not only hits headlines but also the titles of peer-reviewed scientific literature?  A vast number of papers have been published that claim it is the mycotoxins that result in the numerous health effects associated with exposure to WDBs.  Some of the evidence shows an increase in cell cytoxicity, which results in the release of certain cytokines.  However, most papers indicate that exposure to elevated mycotoxins results in immune suppression, not sustained release of pro-inflammatory cytokines that would inherently require intact, activated immune cells. 

Other papers purport that the mycotoxins have a direct effect on brain function, which may result in some of the neurogenic symptoms experienced from exposure to WDBs.  In the considered opinion of this author, the evidence compiled to support the mycotoxin hypothesis as described above is far lacking compared to the evidence supporting the a chronic inflammation hypothesis.

To bring this full circle, the published literature from several fields of academia suggests that the probable reason the Brown University study found a link between WDBs and depression is that biological and chemical agents released in these environments cause chronic inflammation in genetically susceptible individuals. 

By Jim Rosenthal, CAFS

Between July and September of 1994 technicians in the clinical microbiology laboratory of Wilford Hall Medical Center at Lackland Air Force Base in Texas found Aspergillus niger in 17 clinical samples submitted for 15 patients at the hospital.  This caused a great deal of consternation for two reasons:

      1. The incidence of Aspergillus niger had been very low.  In fact, there had been only two positive A. niger tests in the preceding twelve months.

      2. Exposure to Aspergillus species could lead to very serious consequences for the immunocompromised patients (such as those who had received bone marrow transplants) at the hospital.  Such exposure could lead to invasive aspergilliosis which has been shown to be fatal in 85% to 95% of these patients.

The concern was that the hospital might have a serious epidemic on its hands.  Except there was something else that was strange.  None of the patients were showing any signs of illness, and over half of the samples were taken from patients who were in a very low risk group for a positive test including one woman whose urine specimen was taken during a routine obstetrical evaluation. 

Fearing the worst, the hospital immediately called in a team of experts.  They conducted a series of experiments, but were unable to determine the cause of the high levels of test results for A. niger.  As a precaution they asked the laboratory personnel to clean the laboratory biological safety cabinet (BSC). 

In doing so the lab people noticed that there was a black material on the bottom panel, but they did not take a culture.  After six more failed samples, they tested the high efficiency particulate air (HEPA) filters in the BSC and found they needed to be replaced 4.5 years prematurely.   Once the HEPA filter in the BSC was replaced, the “pseudo-epidemic” ended.

Investigation of the events leading up to the outbreak showed that, just after the BSC was installed, there was construction at the hospital to revise the ventilation for the pediatric clinic one floor below the microbiology lab.  This included the installation of a new ventilation duct from the pediatric clinic through the lab.  To construct the new duct, workers jack-hammered a 6-foot by 6-foot hole in the ceiling.  No barriers were used to minimize the dust in the laboratory and specimen processing continued as usual during construction.  No wonder they had contaminated samples!

As bizarre as this story sounds, other instances of careless and unsafe construction related incidents continue to happen in other medical facilities.   According to the Centers for Disease Control and Prevention (CDC), an estimated 90,000 patients die each year from nosocomial (hospital-acquired) infections. From that number, it is estimated that about 2,000 to 3,000 deaths are associated with infections caused by airborne microbes.  It is probable that at least some of these deaths are related to improper construction techniques and controls.  Using proper procedures during construction in medical facilities is important for infection control.  In this article we would like to review some of these procedures with particular emphasis on controlling contaminants with differential air pressure and filtration.

Air Pressure is Powerful Stuff

Air moves to achieve pressure equilibrium.  Consequently, a room that is under positive pressure will have air moving out of it to equalize with the surrounding area.  Conversely, a room under negative pressure will retain air in the space and draw air in from the surrounding areas.  This phenomenon is very powerful.  In fact, most of the winds on earth are created by differential pressure, which is why we hear the meteorologists talking about high and low pressure fronts.  This differential in air pressure between spaces can be used to control particle movement.

For example, in a hospital there are protective environment (PE) rooms to protect patients from airborne contaminants.  These are used for immunocompromised patients such as those who have had bone marrow transplants, are HIV positive, or have open wounds or burns.  These rooms are kept with a positive differential pressure in relationship to their surrounding environment.  On the other hand, there are also airborne infection isolation rooms (AIIR) that are kept in negative pressure so that whatever is in the room stays in the room and does not contaminate the rest of the indoor environment.  A prime example for the use of AII rooms is for the management of patients with tuberculosis.

Differences in pressure are created by mechanically adjusting the supply and exhaust air.  A negative pressure room will have greater exhaust air (going out of the space) than supply air.  A positive pressure room will have more exhaust air than supply air.  According to the American Institute of Architects (AIA) “Guidelines for the Construction of Health Care Facilities” the pressure differential should be about 0.01” water gauge (w.g.) or about 2.5 Pascals (Pa) for AII rooms and a pressure differential of 0.03” w.g. or 8 Pascals for PE rooms.  For construction purposes the difference in pressure can be greater but never less than the above recommendations.

To simplify this a little, just remember that if you want positive pressure in a space so that you can minimize the introduction of particles, you bring in air from outside the space.  If you want negative pressure so that you can minimize the release of particles from a space, you need to exhaust air outside that space.

Filtering the Air for Particle Control

The proper differential pressure allows us to keep construction particles flowing in the desired direction.  The next step is removal of those particles from the air before they can create a problem – either to the health care facility and its patients or to the outside environment.   To accomplish this we need to use an array of different filters from a polyester pad or pleated filter used as a pre-filter to a final HEPA (High Efficiency Particulate Air) that is challenge- tested with results showing a removal efficiency of 99.97% of the particles 0.3 microns and above.

Health care facilities have special filtration requirements depending upon the purpose of the area served.  These requirements are specified by various bodies including the AIA, the CDC, the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) and others.  While these requirements go beyond the scope of this article, they are readily available through public sources.   Suffice it to say that the filtration requirements are designed to provide the best and safest air for patients and health workers.

Of equal importance is the proper installation of filters and filtration devices.   Following sound installation procedures such as gasketing and “in-place” challenge testing is the only way to ensure the filters will perform as required. 

The third important component of controlling airborne infection is ventilation to provide enough air exchanges per hour (ACH) for the dilution of pollution.  We don’t have enough space here to discuss this component in detail.   Recommendations call for 12 ACH for both PE and AII rooms.

Controlling Contaminants In Medical Facilities During Construction Activities

There are three basic types of construction in and around health care facilities that need to be dealt with for particle and contaminant control.  The first is construction (or demolition) that is taking place near an existing facility.  The second is the construction of a new facility.  The third is reconstruction or adding on to an existing facility.  Each has different differential pressure and filtration requirements.

First would be the control of contaminants in a health care facility in close proximity to construction (or demolition).  The most obvious problems would be a big increase in construction dust and unearthing and aerosolizing of microorganisms.  It is recommended that all pre-filters and all standard filters used in non-critical areas be changed before construction begins to minimize disruption during the construction process.  It is very important to check all filters regularly during construction since they obviously will get dirty quicker.  Replace as needed.

While this sounds easy, unfortunately, it is where some people involved in the maintenance of health care facilities decide to become “creative.”  The first thing they think about doing is to decrease the efficiency of the filtration.  After all, the existing filtration is loading up with contaminants way too quickly.  Less efficient filters will load slower and will last longer.  This has the consequence of final filters loading more quickly (at a much higher replacement cost) and all of the components of the HVAC system including coils and duct work building up with more dirt.  This results in higher HVAC system cleaning costs and lower operating efficiencies.  So it is important to resist the temptation to go with less efficient filters.  Likewise, it is also important to replace filters when they are loaded.  Loaded filters can drop air velocity to the extent that the building can become depressurized.  More frequent filter changes is just a cost of doing business in a health care facility in close proximity to a construction site.

The second “creative” approach is to shut down outside air intakes on the HVAC system.  The HVAC systems of health care facilities are designed to take in “fresh” air at a ratio of anywhere from 10% to 100% of the return air in the system.  This is done for a number of reasons including the dilution of pollution and the replenishment of oxygen in the building.  They also do it to create positive pressure.

This positive pressure is the best defense against infiltration of the contaminants from the construction site.  When someone closes the dampers and shuts down the outside air intake they might think they are keeping the dirt out of the HVAC system, but they are depressurizing the building and allowing contamination of the structure, the equipment and the patients in the facility.   If anything, the dampers on outside air intakes should be kept open at all times during the construction to maintain adequate positive differential pressure.

New construction of a health care facility generates its own set of issues on avoiding contamination.  Most health care building construction today involves the completion of the outside building envelope and then the activation of the HVAC system.  This is done before any interior finish out.  This procedure helps to “dry out” the building.  However, it does present some challenges to keep the HVAC system clean.  If possible, cutting return openings in the duct work is done very late in the construction process.  In this case the system is run using outside air. 

Once the return air openings have been cut they should be covered with filtration media or pleated filters.  These filters load quickly with construction dust and should be changed frequently.  Changing these construction filters on a weekly basis is not unusual.

Depending on the amount of return air used and the speed of the HVAC fan, there can be very high air velocities at these openings.  This usually necessitates the installation of a temporary filter rack with a support grid to keep the filter in place and to avoid “bowing” of the filter.

Before turning on the HVAC system, construction filters should be installed in the holding frames or modular track framing systems.  According to the National Air Filtration Association’s “Installation, Operation and Maintenance of Air Filtration Systems Manual” (IOM Manual), these filters should be at least the same type, efficiency and capacity as the filters specified for the operating system.  These filters should be replaced when they are “loaded” as indicated by pressure drop measurements or when the HVAC system is ready to be turned over to the building owners.

The NAFA IOM Manual recommends that in any supply system incorporating HEPA filters that they be installed as soon as ductwork is completed and cleaned so that the ductwork will stay in this condition.  To prevent damage to the HEPA filter the IOM Manual also recommends covering the face of the filters with temporary covers until the ductwork containing the filter is put into operation.

Proper installation of filters is extremely important in health care facilities.  Special attention should be given to ensure that filter banks have the proper spacers, seals and gaskets to provide an airtight fit and avoid filter bypass.   The consequences of improper air filter installation can be substantial.  Dr. Jeffrey Siegel of the University of Texas at Austin has found that small gaps between filters can dramatically drop filter efficiency.   For example, he found that with a 10-millimeter gap between filters the efficiency of a MERV 15 filter would be reduced to that of a MERV 8 filter.  

Air follows the path of least resistance.  Generally, the higher the MERV, the greater the resistance and the more loss in efficiency to air bypass.  Considering the fact that many hospital applications require MERV 14 filters as the final filter, the consequences of improper filter fit can be substantial.

And now for the biggest challenge – what does one do to control contaminants in a health care facility in operation during construction or reconstruction at the facility?  For advice on this subject we talked with Andrew J. Streifel, MPH, of the University of Minnesota.  He is a hospital environment specialist and has been involved in this field for over 25 years.  He is on the AIA guidelines revision committee and has served as a technical expert for the CDC on environmental infection control issues pertaining to air and water.

“Communication is the key to a successful project.  Everybody has to be involved.  That includes the staff, medical practitioners, contractors, architects and engineers.”  said Streifel.  In order to facilitate this communication, Streifel was involved in developing the “Infection Control Risk Assessment Matrix of Precautions for Construction & Renovation” for the American Society of Healthcare Engineering (ASHE) of the American Hospital Association (www.ashe.org/ashe/codes/cdc/index.html).

This “decision-tree” document lays out the types of construction (Type A being inspection and non-invasive activities going to Type D which is major demolition and construction), and an identification of the patient risk groups (patients in office areas to patients in AII rooms) into a matrix.  The end results are “Classes of Precautions” required for each project type.   Each Class has specific precautions required.  For example, it states that a negative air machine with a HEPA filter needs to be used in Class III and Class IV construction projects.

Both Class III and Class IV construction projects use the same basic precautions when it comes to differential pressure and filtration.  The first step is to seal off the area where the construction is being done.  This can either be accomplished with sheetrock, plywood or plastic.  The HVAC system should be removed or sealed to prevent contamination of the duct system.  Once the sealing has been completed it is necessary to use a negative air machine.  These machines have a blower and run the air through a HEPA filter before exhausting it to the outside of the building.  The machines create negative differential pressure and remove airborne contaminants from inside the construction area. 

The HEPA filters on a negative air machine can load up quickly with large particles unless they are pre-filtered.   Polyester pads make an inexpensive but effective pre-filter for most applications.   

Conclusion

Using proper air pressure differentials and proper filtration play a major role in controlling contaminants during construction at health care facilities.  How well do they work?  According to Streifel, who has assisted more than 400 hospitals with environmental control issues pertaining to air and water, they are among the most important considerations:  “If you have your pressure, filtration and ventilation rates right, you will be able to keep the air clean.  Each of these physical ventilation parameters needs to be measured and monitored regularly.  Particle counts and sampling for fungi are useful to reassure you that things are working correctly.   But it is the air control functions that prevent infection.” 

Jim Rosenthal is Chairman and CEO of Tex-Air Filters in Fort Worth, Texas.  He is the Treasurer of the National Air Filtration Association and President of the Asthma and Allergy Foundation of America – Texas Chapter.  He can be reached by phone at 817-261-3791 or by e-mail at jimrosenthal@allergyclean.com.

Cutline for photo

Andrew Streifel, Hospital Environmental Health Specialist at the University of Minnesota, is shown here checking air pressure in a room.  For complete instructions on measuring differential pressure, filtration and ventilation see the Minnesota Department of Health manual “Airborne Infectious Disease Management.” (available at http://cpheo1.sph.umn.edu/meret/)