RENTERS BEWARE: APARTMENT HVAC CLOSETS CAN BE SOURCES OF MOLD AND DEGRADED IAQ

Furnace on water damaged OSB platform. The return plenum is located beneath the platform.

A common practice in multi-story apartment and condominium complexes is to house the furnaces in closets that are located on the patio or balcony for each unit. The closets are aligned vertically in each building. Although the orientation is convenient for plumbing access, numerous water damage issues are inherent to this type of HVAC set-up.
Water damage from plugged condensate drain tubes or malfunctioning condensate drain pans is common. Slimy biological growth in PVC tubing and drain pans pan causes overflows. Current or historical overflows from the pans will appear on the sheet metal plenum under the A-coil. Drips and mold growth from malfunctioning units above a closet are commonly apparent as drip stains or growth on the ceiling and walls of the closet.
Water damage caused by freezing and thawing of the AC coils is common in apartment HVAC systems. Filter changes are often left in the hands of uninformed tenants. Plugged filters prevent sufficient air flow to the coil, causing it to freeze. As the coil warms up, the ice thaws, releasing large amounts of water into the return plenum, floor system of the apartment, furnace platform, or furnace closet below the damaged unit.
Another issue associated with stacked HVAC closets is the installation of the furnace on a platform, which is commonly constructed from plywood, drywall, or oriented strand board. When wet, all of these materials support the growth of mold and bacteria, which can produce various toxins. Additionally, the glues and resins in these materials can be liberated when wet.

Ceiling of furnace closet showing water entered from HVAC closet above.

The return plenum in furnace closet systems is located beneath the platform, with the underside of the platform being the top of the plenum, a concrete slab serving as the bottom, and the walls of the platform forming the sides of the plenum. In addition to being difficult to clean, a water damaged common plenum provides both a contaminant source and transport pathway.  Dust mites, insects and their fecal material, garbage, cigarette butts, contaminated chunks of paper, and rodent feces are just a few of the treasures that have been recovered from plenums under furnace platforms.
When damage does occur, the underlying cause of water must be corrected. This involves replacing plugged drain tubing, cleaning drip pans, cleaning coils, and changing filters. For consistency, preventive measures in the form of routine inspections and HVAC maintenance should be the responsibility of the management company or maintenance staff.
Addressing the consequences of the water damage, whether it manifests as biological growth or deteriorated building materials, is imperative to appropriate HVAC hygiene and good indoor air quality. Contaminants on water damaged plywood, OSB, and drywall in the furnace closet and on the furnace platform can cause adverse health effects, whether the growth is active or historical. Once dried, mold and bacteria engage in survival mechanisms that can include toxin production and increased sporulation. When dry, the contaminants are easily liberated into the airstream.  Mold remediation is required when building materials in furnace closets become contaminated. The remediation involves two components (1) removal of the mold or contaminated building material and (2) addressing spores that are released from areas of actual growth. Engineering controls, containment barriers, HEPA filtered air filtration devices, personal protective equipment, HEPA vacuuming, and damp-wiping are all essential for safe and effective remediation in water damaged furnace closets.

Return grille located inside of the apartment behind the furnace platform. Stains show repeated wetting fo tack strip.

MOLD CLEAN-UP AFTER A HURRICANE IS NOT A DIY PROJECT

Hidden mold on underside of sub-floor after a flood

http://www.thedoctorstv.com/videolib/init/8286_

The above link provides some good information on the hazards that are inherent to flooded buildings. Good information in the clip includes:
• Chemicals, such as pesticides, gasoline, hydrocarbons, rotted food, and other harmful agents can be transported indoors with flood waters.

• Animal fecal material, carcasses and pathogens are inherent to flood waters.

• Fungi (mold) grow indoors on drywall, wood, and other cellulose contents.

• Mold that grows indoors can make people sick.

• Moldy drywall must be discarded.

The overall message that water damage to buildings is unhealthy was very clear in the news clip. However, due to the shortness of the clip, information was limited. The public should be aware of that many hazards exist after floods. As reported by the World Health Organization (Dampness and Mould, 2009), other harmful agents in water damaged buildings include bacteria, endotoxins and exotoxins from bacteria, mycotoxins from mold, chemicals released from wet building materials, insects, and other contaminants that can be transported indoors with surface and ground water.

The media clip does fall short relative to its discussion about clean-up. The recommendations from the interviewed mold expert do not emphasize that flood clean-up is not a do-it-yourself project. Although the reporter and expert donned protective gear prior to entering a flooded house, the importance of hazard training and medical clearance for using personal protective equipment is not addressed. This could turn into a situation where a little knowledge could be dangerous.

The issue of restoring wood after a flood was misrepresented in the clip. The expert suggested that unless wood was rotted, abrasive cleaning would effectively restore mold contaminated wood after a flood. This is information is not correct. Wood that has been in contact with the flood water is contaminated with the same chemical and biological agents as the drywall that the expert states must be removed. Abrasively cleaning of wood will only address the outer accessible surfaces. Wood has six sides. Ignoring the surfaces that cannot be accessed for cleaning (interface between bottom plates and flooring, stacked studs, etc.) are typically the most contaminated because they remain wet for the longest periods.

The surfaces with trapped contaminants can cause exposure hazards long after restoration and re-build are complete. Contaminants that remain on wood in floor, ceiling, and wall cavities can be liberated with pressure differentials, physical disturbances, and normal living activities. Since people can react to dead mold and other contaminants that remain after a flood, failure to address the “hidden” surfaces could be quite dangerous, especially to people to young children, elderly people, asthmatics, or those that are immune-compromised. Appropriate remediation scopes for damages from catastrophic water losses, such as those caused by Hurricane Sandy, are paramount to preventing future indoor air quality problems.

BASEMENT FLOODS: Primary Damage and Secondary Mold Growth

Flooding of basement, whether the water travels through foundation walls, is caused by a broken pipe, or backs up from a drain, requires immediate action to prevent exposure hazards from mold, bacteria, chemicals, pesticides, and other contaminants. Just as families should prepare and rehearse plans for addressing fires, pre-emergency preparedness is essential to safeguarding health and property values after flood events.
Flood Preparedness
I. Identify the source of water. This is important for several reasons:
• The severity and types of contaminants in flood situations are defined by the origin of the water. For example, if the flood water has fecal material, toilet paper, etc. that are indicative of a sewage back-up, the water has the potential to cause significant harm to exposed individuals. In addition to mold, bacteria, toxins, and human pathogens, sewage water can be contaminated with viruses, chemicals, and pesticides.
• The origin of the water can define whether or not insurance coverage is available. Many homeowner insurance policies include riders for sump pump failures and drain back-ups. Homeowners should be aware that the coverage is not always mentioned by the agent. The cost is typically less than $100 per year, but most consumers don’t know that it is not included in the general policy. Additionally, most insurance policies do not cover damages associated with ground water intrusion that enters through foundation walls or basement windows.
• The origin of the water could determine if liability is to a municipality for negligence, such as insufficient maintenance of storm drains or pumping stations, can be demonstrated.
• The origin of the water can assist in developing an appropriate remediation scope. If flooding is from ground water or sewage, high velocity fans should not be utilized for drying until decontamination is completed. The fans can blow contaminants from affected to non-affected areas. If the water originates from a clean water source, such as broken supply line for a washing machine, high velocity air movers and dehumidifiers should be employed as soon as possible. If surfaces are dried within 24 – 48 hours, mold will not likely grow.
II. When to call your insurance company
In most cases, the insurance company should be called sooner than later. Delaying notification could cause denial of claims or delays in appropriate structural drying, which could promote mold growth that might not be covered by an insurance policy.
Homeowners should know in advance what types of water losses are covered by their insurance carrier. Knowing what the deductible and other out of pocket expenses are for a claim , as well as understanding whether additional riders are needed for mold, drain back-ups, and sump pump failures, is imperative to making wise financial and risk assessment decisions. Also, knowledge of what is and is not covered will assist in decision making regarding whether making a claim is advisable, as making claims that are not covered might compromise the insurability of a home or could cause rate increases.
III. When to call in professionals
The answer to this question depends on the origin and severity of water damage, as well as the type of building materials that are affected by water. If sewage, ground water, or storm water affects large or inaccessible areas, gets into a furnace, reaches depths that require wading through raw sewage – call a professional.
If storm, sewage, or ground water does not recede within a few hours – call a professional.
If porous cellulose building materials such as drywall, plywood, insulation, and carpeting is affected – call in a professional. Scrutinize contractors in advance and call immediately.
Since insurance companies usually require that homeowners take action to mitigate losses, having on hand the phone numbers of pre-vetted restoration contractors can save time and money. After major storms, contractors get booked up quickly. If possible, do not rely on your insurance company to pick the contractor. Choose your own independent third party that has a good reputation and appropriate certifications in water damage restoration. Information on certification can be accessed at IICRC.org.
IV. Quick responses
If water recedes to the extent that electrical and biological hazards are not imminent, healthy homeowners can don protective clothing and take action to protect their belongings and the indoor environment. With appropriate precautions, drains should be verified to be open, pumps should be used to remove standing water, and dehumidifies are to be put into operation. Removal of non-restorable contents reduces indoor contamination and minimizes secondary damage from high relative humidity.
Items to be discarded include affected papers, cardboard, books, stuffed animals, stuffed furniture and other non-restorable items immediately. Disposal should be documented with photos and lists, or items should be placed in receptacles until they are documented.
Wet carpeting should be removed as soon as possible. All wet items should be bagged or wrapped in heavy gauge polyethylene. Transport items only after they are bagged or wrapped. If possible, discard through a basement window or door to minimize cross-contamination to living spaces. Be mindful that contaminants are present, and healthy individuals with no history of breathing disorders are the only candidates for self-remediation. Protective water resistant overalls, gloves, rubber boots, and P100 respirators should be worn.
V. Habitability
If occupants experience adverse health symptoms such as headaches, itchy eyes, sore throats, congestion, gastrointestinal disorders, dizziness, or other flu-like symptoms, the home should not be occupied until decontamination is complete and verified by an independent third party consultant. Infants, elderly people, diabetics, people on immune-suppressive drugs, respiratory illnesses, or heart conditions should be removed from the home until decontamination is complete and verified. A physician should be contacted if symptoms develop after exposure.
VI. Independent third party consultant
If a homeowner suspects litigation, confrontation with the insurance company, or serious health issues, it is strongly advised that an independent third party mold and water damage consultant be hired to assess damages and develop an appropriate remediation scope. It is a good idea to have names and numbers of vetted consultants available in advance.

Cladosporium is Not Always Harmless

Cladosporium cladosporioides will frequently colonize on damp wood, while Cladosporium sphaerspermum will colonize on damp insulation

Recently, I reviewed several reports from other consultants who discounted the presence of Cladosporium in spore trap air samples, claiming that this mold was not of concern because it was the most common in the outdoor sample.  Following are a few reasons why their conclusions could be faulty:

1. Cladosporium found in air samples is often considered non-problematic because Cladosporium is generally the most common mold found in outdoor air.  However, if there is actual growth of Cladosporium indoors, which would require excess unplanned moisture, other contaminants that are inherent to water damaged buildings will also be present.  When conditions exist for indoor mold and bacteria growth, endotoxins, mycotoxins, spores, glucans, and other allergens and inflammatory agents will be present.
2. Generally, the first molds to colonize on wet building materials are Penicillium and Aspergillus.  These two genera cannot be differentiated in spore trap samples and are often under-reported.
3. When only the genus can be identified in samples, as with spore trap methodology, indoor and outdoor fungal ecologies cannot be conclusively compared.  Cladosporium found outdoors might be Cladosporium herbarum, which is commonly found on decayed vegetation, while the Cladospoirum indoors could be Cladosporium sphaerospermum, which grows on water damaged insulation.
4. Even if Cladosporium is the same species as outdoors, sensitized individuals could react when concentrations are elevated indoors.

Lesson learned:  Spore trap air sampling alone is a very inconclusive tool for assessing the moldiness of an indoor environment.  Claims that Cladosporium is not a problem can be faulty.

Recommendations:

A detailed visual investigation is the single most important part of a mold investigation.  Sampling should only be performed to answer a question.  Spore trap samples cannot conclusively answer most questions.  A combination of air, dust, and surface samples that are analyzed by culturing or MSQPCR (Mold Specific Quantitative Polymerase Chain Reaction) is typically necessary.

The Shortcomings of Shortcutting A Mold Remediation Project

My mom’s words of wisdom, “Any job worth doing is worth doing right,” never rang

Contaminated drywall must be removed under controlled conditions.

truer than in situations where partial remediation is viewed as being better than no remediation.  Contrary to this misconception, no remediation is better than substandard remediation.  Case in point – a family inherits a home that has been unoccupied for an extended period, and had not maintained for more than ten years.  Water intrusion into the basement and attic caused mold growth to building materials that were in contact with water.  Sustained high humidity resulted in secondary mold growth due to condensation on interior drywall.  Testing revealed concentrations of Penicillium and Aspergillus in the range of 80,000 to 100,000 counts per cubic meter of air.  Outdoor concentrations of spores in these genera were less than 1,000 c/m³.  Toxigenic mold species, such as Stachybotrys chartarum, were also identified.

In the throes of financial difficulties versus living rent-free, the family made a decision to move into the contaminated home and perform remediation in a piecemeal fashion.  They believed that small efforts to remove mold would cumulatively achieve the desired end product of good indoor air quality.  However good their intentions might have been, the reasoning was flawed.  Unlike cosmetic or structural renovation projects, mold remediation cannot safely be performed “a little bit at a time”.  Effective remediation requires removal of mold contamination along with addressing spores that are liberated from areas of actual mold growth.

Attempting to live in a contaminated home while performing remediation one step at a time is similar to paying minimum monthly payments on a high interest rate credit card.  There is no light at the end of the tunnel, and the problem compounds over time.  If one area is effectively remediated, yet contamination remains in other locations, re-contamination to the cleaned area will occur.  Additionally, with ongoing exposures, individuals become sensitized and progressively react to  lower concentrations of mold.

DEAD MOLD CAN CAUSE ADVERSE HEALTH EFFECTS

Mold in Wall Cavity Can Enter Living Space

I was recently surprised in several situations where consumers were told that dead mold is okay because it does not cause adverse health symptoms.  The fact that dead mold, toxins, and mold by-products can cause adverse symptoms is not a new concept.  It was certainly included in all of the beginner mold training classes that I attended more than fifteen years ago.  Also, in 2001, EPA published information on the adverse health symptoms that can be caused by dead mold (Mold Remediation in Schools and Commercial Buildings).

Overhearing this kind of information relayed to a customer at “big box” store where the associate told a consumer that killing mold with a certain product was all that was needed to remediate a moldy attic caused me cringe.  Listening to a remediator argue this point with a homeowner who was sick after a botched remediation job made my blood boil.  Consumers look to professionals to guide them.  Mis-information is not only unethical, it can cause serious health problems.

Allergic type reactions from dead mold, mold spores, fragments of molds, and mold metabolites (toxins, volatile organic compounds) has been widely accepted in the medical field for decades.  Some of the health effects from mold, whether it is dead or alive, include:

• Irritant reactions, such as itchy eyes, sore throats, and rashes
• Suppression of the immune system
• Inflammatory responses that affect the liver, kidneys, and other organs
• Multiple chemical sensitivities
• Chronic fatigue
• Brain fog

The ability for dead mold, mold fragments, and mold metabolites to cause adverse health symptoms is one of the primary reasons that mold remediation standards of care from EPA, OSHA, the Institute of Inspection, Cleaning, and Restoration Certification require containment barriers, engineer controls, and HEPA vacuuming when moldy building materials are disturbed.

When Did the Dummying Down Start in the Mold Remediation Industry?

When I encounter effective mold remediation projects by contractors that have the appropriate knowledge, training, and ethics to protect both a structure and its occ

Mold Contaminated Building Materials Left Under Staircase After Remediation

upants, I am proud of our industry.   However, increasingly I coming across mold remediators who either do not know or do not want to do what the standards of care are designed to achieve.

Mold Remediation Emergence

In the late 1990’s to the early 2000’s the restoration industry experienced a big shift away from “rip and run” techniques for mold removal to detailed step-wise remediation  performed trained technicians in accordance to a mold consultants scope.   A crucial impetus behind safe mold removal was a series of well publicized case studies in which serious adverse health symptoms were reportedly associated with exposures to toxigenic molds in schools, residential dwellings, and court houses.

During those early years of mold consciousness, most residential and commercial insurance policies covered mold damage that was related to sudden water events, such as water intrusions into roof systems after rain storms, refrigerator ice maker supply line failures, and plugged AC condensate pans.  Coincidently, at the same time, mixed winter conditions in the midwest and northeastern parts of the United States caused ice dams and consequential mold damage to roof systems and attics, which added to the mold burden caused by storms and hurricanes in warmer parts of the country.   A void of qualified and certified mold remediators and consultants triggered the development of new training centers that were flooded by contractors and consultants who were eager to become certified.  Before long, various governmental, professional, and trade associations established guidelines that ultimately became the standards of care.

As an indoor air quality consultant, I performed thousands of pre and post remediation assessments in the twentieth and early twenty first centuries.  Overall, I encountered contractors that were eager to learn the why’s and how’s of effective mold remediation.  I definitely saw improvements as contractors sought to be at the top of referral lists and desired to stay out of the courtroom.

Mold Remediation Downturn

All seemed good in mold remediation land until the mid-1990’s when the insurance companies plugged the flow of money for mold-related losses.   Some of the important events that I believe triggered the shut-off of mold insurance included a landmark case in Texas where a jury awarded the Melinda Ballard and her family $32 million dollars for property and compensatory damages associated with mold from a covered water event in their 11,000 ft² mansion.   Another important influence was that insurance companies were paying out more money than necessary for many claims, primarily because historical and loss related damages were not differentiated.   Additionally, with so many losses and not enough specialized adjustors, decisions were frequently left up to contractors that were pressured from homeowners to remove all mold.  Ultimately most insurance companies capped the pay-outs for mold related claims or completely excluding mold coverage.

With exclusions in mold coverage, many companies that specialized in mold remediation closed their doors.  Most of the survivors shifted their focuses to providing water and fire restoration.   Companies that survived with mold remediation as their primary service developed special niches, such as physician recommendations, custom builder alliances, and specialized client referrals

State of the Industry

The downward spiral for mold remediators seemed to level off after 2010.  Most large insurance reliant companies still provide mold remediation, and a few specialized mold remediation contractors have survived.  Unfortunately it seems that the “how to’s” for the quality of work that emerged in the early 2000’s did not get passed on as field technicians and supervisors were replaced.  Surprisingly, some companies that still tout mold remediation services have no certified mold remediators in their company and/or are not covered for mold damages.  For many of those that have veteran employees with certifications, the basics of “removal under controlled conditions” appear to be awash with restorative drying policies and procedures.

My observations on several recent “post remediation” inspections s prompted writing about this topic.  Witnessing what I considered botched remediation that lacked common sense surprised me on the first few jobs.   Seeing similar conditions on numerous subsequent jobs left me horrified.    The previous eagerness  that I had become accustomed to seeing in technicians who wanted to be the best remediators  is far too often replaced with rolling eyes, impatience, and indifference.  For the consumer, this trend might have devastating health effects.   Because the majority of homeowners do not know what to expect from a mold remediation contractor, sub-standard remediation will usually not have immediate adverse consequences for the contractors.   Hopefully, health complaints and costly litigation will not be necessary to stop the dummying down and restore credibly to this important industry.

Beware of Some Antibacterial Cleaners and Personal Care Products

A germ-fighting chemical added to many soaps, toothpastes and fabrics can interfere with how muscles contract, new research shows.

A chemical, triclosan, an antibacterial additive in some cleaning compounds can affect calcium channels that regulate cell activity.  Researchers have identified levels of triclosan that can be lethal to mice in humans.  It is believed that this chemical can cause a reduction in muscle mass in humans.

Some individuals who are adversely affect by chemicals, molds, bacteria and other contaminants in water damaged buildings use antibacterial products to prevent exposures to biological agents.  If products contain triclosan are used, these individuals might experience muscle loss they attribute to re-exposure to mold, when the culprit is actually the cleaners or personal care products that  they use.

For more information on triclosan go to  http://www.sciencenews.org/view/generic/id/343045/title/Antibacterial_agent_can_weaken_musc

Mold Can Be Exhausting: Fatigue and Other Symptoms

Exposure to mold, mold toxins, bacteria, endotoxins, chemicals and other contaminants in water damaged buildings (WBD’s) can cause multi-system inflammation that manifests as fatigue, cognitive impairment, memory fog and other symptoms.  At a recent inspection, I advised a family to move out of the home that they had owned for approximately eighteen months.  Pervasive rotting of the of wood structures on the exterior veneer, moldy odors, signs of concealed water damage, and visible mold were sufficient to conclude that biological contamination existed in the indoor environment.  Although mold naysayers might claim that such a claim could only be made with medical confirmation of a proximate cause between the mold and illness, I considered it my professional and ethical responsibility to identify the potential hazards to the homeowners.  The concerned parents took the advice seriously.

 

Less than a month after moving out of the house, the parents reported that their young child, who previously displayed signs of lethargy and low energy, was participating in sports and displayed notable improvements in her energy level.   Sampling confirmed the presence of high concentrations of Stachybotrys, Aspergillus, Penicillium, Wallemia, and Aureobasidium, which are fungi that grow in water, damaged buildings and are associated with allergenic, toxigenic, and pathogenic health effects. 

 

 

MOLD TEST KITS: Why You Should Not Do-It-Yourself

Using a “do-it-yourself” (DIY) mold test kit to evaluate whether a home has a mold problem makes about as much sense as replacing an annual doctor exam with using a thermometer to take your temperature.  Just as a person could be very ill while maintaining a normal temperature, a home could have a serious mold problem, even though a DIY test was negative.

Designing, executing, and understanding a comprehensive indoor mold assessment is difficult enough for professional mold consultants.  The best ones understand that building dynamics, hidden mold, historical damage, sampling techniques, analytical methods, and many other factors can influence the accuracy and effectiveness of diagnosing indoor mold problems.

Unlike chemical testing, no dose response curves have been developed for mold exposure.  Therefore, sample results will often raise more questions than answers.  Mold spores are always present in indoor environments. They enter buildings through doors and windows, and usually are not a problem unless they have suitable nutrients for growth.  All building materials can support mold growth IF sufficient moisture is present.  Moisture can come from leaks, floods, or excess humidity.

When sufficient moisture is present, certain molds that are usually minor constituents of outdoor air grow disproportionately to predominant outdoor molds that grow on decayed vegetation.  The molds that grow indoors on wet drywall, wood, and other cellulose materials are most frequently in the genera, Aspergillus, Penicillium, Stachybotrys, and Chaetomium.  These molds can present health problems when they grow indoors.  In addition to allergic reactions, triggering of asthma, and infections, many molds that grow indoors produce secondary metabolites, such as toxins.   The tightness of indoor environments can promote exposures and adverse health to occupants of water damaged buildings.

The single best tool in a mold assessment, whether it is performed by a professional or a do-it-yourselfer, is a detailed visual inspection.  The simplest inspection involves observations of mold growth after a water damage event.  If you see it, yes it is there, and must be addressed to prevent air quality problems.  More involved inspection that require professionals are those in which prior unmitigated water damage has been concealed or construction defects result in hidden water damage in ceiling, wall, or floor cavities.

For the do-it-yourself mold tester, the best that can be expected from a home test kit is to identify the type of mold is visibly growing on a surface.  However, if it is growing, the source of moisture must be corrected and the mold must be removed under controlled conditions.  Since remediation procedures are not dictated by the type of, testing is usually a waste of money.  If the area of growth is small and a low likelihood exists for hidden mold, addressing the mold according to EPA guidelines found in A Brief Guide to Moisture, Mold and Your Home (epa.gov) is sufficient.  If the mold covers a large area or hidden mold is suspected, a professional remediator is usually required to avoid hazardous exposures and cross-contamination to unaffected areas.

The worst outcome from a do-it-yourself mold test kit is that negative results will give a false sense of security when in fact hidden mold problems do exist.   False negative are common in culture plate kits (petri dishes) that instruct the user to place the open plate in a room for a specified period of time to collect mold that settles from the air.  The lab reports for settling plates might list several types of mold that grew the petri dish.  However, the data is usually inconclusive at best.  One problem with “settling plate” is that all molds do not settle at the ratio in which they are found in the air.  Therefore, many species can go undetected.  Another issue is that the actual concentrations of mold spores per volume of air cannot be calculated because the sampling method cannot quantify the amount of air to which the culture plate is exposed.  Additionally, the methodology does not address whether the molds entered from outdoors or were from areas of actual indoor mold sources.

Another type of test that might be recommended for the culture plates is to tape the open culture plate to a supply register to allow the air from an operating HVAC system to impact the plate for a specified time.  Unfortunately air exiting from the airducts does not necessarily represent air within the home because the air that passes through a filter before impacting the culture plate.  Additionally, the likelihood that contaminants would actually be released from an area of growth, enter the air stream, be sucked into the return ducts, pass through the filter, and ultimately end up on the culture plate is very low. 

Swab type test kits are commonly available for DIYers.  Directions generally instruct the user to wipe the swab over a small area (usually 1 sq. inch) of suspect mold growth.   The resultant lab report might list several molds that were found in the swab sample, but this method cannot differentiate between settled spores and what might have actually been growing on the surface.   In either case, the results should not be mistaken to represent the moldiness of the whole house.

Still another type of surface sample that can be found in home mold test kits is a tape lift sample, which involves using clear cellophane tape to “lift” suspect mold from a surface.  This type of sample can be useful in identifying not only the type of mold that is present on a surface, but can also differentiate between actual mold growth and spores that settled from the air.   But the sample would be representative of the tested area only and would not provide information on the overall mold conditions in the indoor environment.

Mold testing can be a useful tool in the hands of a knowledgeable investigator that designs a sampling plan to address a question that cannot otherwise be answered.  Unfortunately, even within the mold assessment and remediation industries, few investigators understand the principles of microbiology, building science, engineering, and scientific methods that are required to conduct a meaningful mold investigation.  With so many variables and limitations in mold testing and analytical methods, “do-it-yourself” mold test kits are generally a waste of time and money.