Wednesday, July 25, 2018

Maintain your Plants

Having healthy plants indoors is a wonderful thing. Communing with nature and other life forms tends to have a positive impact on the human psyche. Plants produce oxygen and help to eliminate carbon dioxide that humans and other animals exhale. There are also studies that suggest plants help to eliminate mold spores and bacteria. All of the above statements express sentiments with which I substantially would agree. Having lots of plants indoors, however is a double-edged sword.
There is growing evidence that plants do have a positive impact on the quality of the indoor air, so the basic belief or instinctual reaction is valid. It has been demonstrated that plants, and there are specific plants that have been shown to perform better than others, can help to control some airborne microorganisms. Plants can also remove substantial quantities of volatile organic compounds (VOC), including formaldehyde, from the air. Research shows that photosynthetic action of the leaves plus the activity of some soil microorganisms both contribute to this purifying action. English Ivy, Asparagus Fern, and Purple Heart Plant are some of the most effective toxin removing plants.
Indoor plants, however, also have their negative side that often more than counteracts their enhancement of indoor air quality. One of the first items I check when conducting an indoor air quality investigation are plants, which are sometimes more of a contaminant source than they are a benefit. In order to produce sufficient oxygen or to eliminate enough carbon dioxide to have a significant impact on the quality of the indoor air, it would be necessary to have a virtual jungle of plants, but the toxin reduction can still be valuable with fewer plants. The overall effect of indoor plants tends to be quite beneficial in terms of helping to purify the air if they are properly maintained. Plants become a contaminant source due primarily to improper care. Over-watering is not only destructive to the health of the plant, but can result in substantial growth of molds and bacteria. Using wadded up newspaper or paper bags to center a potted plant inside a decorative pot opens up the possibility of mold growth on that paper when it becomes wet when watering the plant. Mold growth on paper or other materials containing high levels of cellulose is often a potentially toxic mold, such as Stachybotrys. This is the notorious villain in most news reports that deal with mold contamination. I should state at this point, that health effects due to inhaling mold toxins is a controversial topic and has not been clinically established. 
Sphagnum moss is a high cellulose containing decorative material
often placed on top of the plant's soil in part to help retain moisture.
Placing this material on top of wet soil, thereby causing the moss to
become wet, can produce mold growth on this material as well.
Again we have mold growth on a high cellulose containing material,
so the possibility for growth of potentially toxic molds.Using a
professional plant service to maintain the plants is by no means a
guarantee that the plants conform to proper indoor air quality standards.
I have found that even though the plants appear to be healthy and
beautiful, they often have the problems presented above. This can
result in mold growth potentially contaminating the air in the vicinity
of the plant and beyond. To ensure that plants are indeed a benefit to the
quality of the indoor air, properly maintain them. There must be certain
restrictions. Those restrictions must include prohibiting the use of any
paper product inside the decorative pot either for centering or any other
purpose.  Sphagnum moss, if it is to be used, must be regularly replaced
in the event that it becomes wet and moldy. It is not as susceptible to mold
growth as paper, but it has been found to be a source of mold contamination
numerous times in my experience.

Carpets - Pros and Cons

Carpeting certainly makes a house cozy and warm during the winter months. Getting out of bed and putting your feet on a warm carpet really beats a cold wood, tile or linoleum floor. The problem is the price we may be paying for this comfort. Whatever is in the air eventually falls out of the air. This particulate can include virtually every conceivable material. Dander (skin flakes), cotton or synthetic fibers, organic detritus (partially decomposed organic matter), and paper fibers are generally the most plentiful materials found in indoor dust. Other materials commonly found include construction dust (calcite or gypsum grains), bacterial cells, fungal spores and mycelia, fiber glass or mineral fibers, quartz grains (sand), paint chips, pollens and other allergens plus a much wider list that would be difficult to exhaust.
No matter how hard you try, carpeting cannot be thoroughly cleaned. To a large degree, cleaning carpets tends to grind in dirt as far as possible to just above the floor or the carpet pad. Even after cleaning, many of the contaminants are still there to do their harm. Remember, dirt is not just dirt. Indeed, dirt and dust consist of many potential irritants, allergens, toxins and pathogens.
Carpets also tend to be susceptible to water damage. Floods from rain and plumbing leaks as well as from overflow of facilities such as water heaters, dishwashers, washing machines and toilets often wet carpets. Unless carpets that have been flooded or severely wetted are dried out quickly, i.e. within 24 to 48 hours, bacterial growth will have already occurred and fungal growth will have started. Repeated wetting will add to such contamination. Even cleaning carpets with water can result in microbial growth unless the drying is very timely.

Fungal and bacterial types found in water-damaged carpets often include high levels of Penicillium, yeasts and gram negative bacteria. Penicillium and yeasts are both potentially allergenic. Species of Penicillium can produce toxins and have potential to be infectious or more usually opportunistically pathogenic, which means infectious for those with impaired immune systems. Gram negative bacteria produce an extra-cellular toxin called endotoxin that can elicit a myriad of health symptoms. Exposure by inhalation to this toxin is associated with a number of pulmonary diseases. Among the symptoms related to exposure by inhalation are fever, cough, body aches, nausea, shortness of breath, chest tightness, airflow obstruction, airway inflammation and low lung function. Endotoxin is one of the toxins that is likely implicated with such situations as "Sick Building Syndrome." Such exposure also reportedly strengthens immune system responses. Because of this strengthening of the immune system, exposure to endotoxin can apparently cause the exposed individual to be more susceptible to allergies or to developing allergic reactions.  This simply means a stronger immune system is likely to react to any substance deemed to be harmful whether it is or not, which essentially is what an allergic response is.

There are certain levels of gram negative bacteria that cause some indoor
air quality authorities to express concern. That rather arbitrary level is one
million (1,000,000) colony forming units (CFU) per gram of dust or other
material. I have often taken samples from carpeting that far exceed the level
of concern.  If you are planning the nearly ultimate in luxury by having your
bathrooms carpeted, please reconsider. That warm, plush carpet may feel
wonderful on your (wet) feet as you step out of the shower or bath, but consider
the contamination in the carpet with continual wetting. Carpeting in such areas
as bathrooms, kitchens and laundries are very likely to become sources of
bacterial or fungal growth no matter how carefully maintained. A soft mat or
rug can be just as comfortable on your feet and is much preferable because it
can be properly cleaned or laundered to limit or eliminate potential contaminants.
The bottom line in terms of carpeting in your home is to keep them dry and
vacuum them often using HEPA (High Efficiency Particulate Arresting) vacuums.

Friday, November 3, 2017

Dust Mites - The Creepy Facts

Dust mites are ugly little arachnids (eight legged creatures related to spiders).  They are microscopic, but you might see one against a black background.  They are quite repugnant little monsters when viewed under a microscope. 

It has been reported that more people are allergic to dust mite allergens than any other single item.  The allergens aren’t just live dust mites, they are dead dust mites, dust mite parts and feces.  The feces particles are particularly allergenic.  Gross, huh?

Dust mites live on dander, or sloughed off skin from humans or animals.  They also eat some molds.  Dust mites tend to be abundant in crowded and humid environments.  The crowd provides the food and humidity provides the water.  They find plenty of hiding places in fleecy material.  Dust mites cannot live in dry climates and will die off when humidity falls below 40%.  But even after they die the problem persists until the body parts and droppings are removed.

Bedrooms are especially favorable habitats for dust mites.  Food supplies are generally plentiful.  Most people spend an average of eight hours in a horizontal position and thus rub off a relatively large amount of skin.  Mattresses, bedclothes, carpets and other fleecy materials can become infested.  Even if the humidity is generally low, some dust mites might obtain sufficient moisture from humidity generated by exhaling and from sweat.

Dust mites don’t bite and are not known to cause any diseases.  The harm is to individuals who have developed allergies to them.  As the concentration of the allergen increases, the allergic reaction becomes more intense.

Symptoms include runny or itchy nose, congestion, sinusitis, irritated eyes, cough, itchy skin, trouble sleeping.  Asthmatics could suffer other symptoms including breathing difficulty/shortness of breath, chest tightness or pain, severe asthma attacks.  Symptoms are likely to be worse in locations where dust mites are present, thus usually in the home.  While dust mites do not bite, just having an allergy to them can result in a rash that may look very much like insect bites.

What can you do about it?

The most successful method of relieving dust mite allergies is avoidance of the allergens.  The other conventional methods of relief include prescription medication and allergy shots.  I would add another method, which could technically be included under avoidance.  Exhausting moisture laden air such as from bathrooms and kitchens is good preventive maintenance to avoid dust mite infestation.

Other methods of reducing exposure to dust mite allergens include:

1) Thoroughly cleaning your house.  Vacuum frequently using a HEPA (High Efficiency Particulate Arresting) filtered vacuum.  Dust using cloths dampened with a solution appropriate for the surface.  If you prefer not to use non-allergenic plastic covers on your mattresses, a regular thorough vacuuming of mattresses should be included in your cleaning routine.

2) Limit the use of carpeting and other fleecy materials.  Carpeting in particular is a magnate for contaminants including a good hiding place for mites.

3) Keep heating and air conditioning systems clean and equipped with efficient filters.
4) Get rid of stuffed animals or encapsulate them in plastic.
5) Launder bedclothes frequently in hot water.
6) Keep pets out of the bedroom.
7)      Keep closets and dresser drawers closed.
8)      Pillows and mattresses can be covered with non-allergenic plastic covers to help keep mites under control.
9)      Maintain humidity levels below 50% and as close to 40% as possible.  Use of a dehumidifier might be necessary in many cases.

Here's a successful investigation:

I was inspecting a home that had been subjected to numerous rain leaks.  Mold growth was suspected in the walls in several locations.  The increasing respiratory and other symptoms of the homeowner prompted our investigation.  He had lived alone in the house for a number of years.  Business trips he took that lasted several days caused his symptoms to subside only to return once he came back home. 

The inspection and testing included taking samples for airborne mold spores in the ambient air as well as inside walls in certain locations.  We did find evidence of mold growth in some of the locations, particularly on the lowest floor of this four level hillside home.

Even though our investigation was primarily geared to mold problems, I noticed something else that might be causing a problem for the homeowner.  The head of his bed was located against the wall right next to the door of the large master bathroom.  The door was wide open and the only exhaust fan was one in the small adjoining room that housed the toilet.  I saw rust on the metal cover for a stereo speaker built into the bathroom ceiling plus faint water marks apparently due to condensation running down the walls outside of the shower.

For this reason I decided to take a sample from the bedding and carpet in the master bedroom for dust mite allergens.  We found substantial mold growth sites in some walls as suspected, but we also detected the highest levels of dust mite allergens of any location in my years working in this field.  If we had only dealt with the mold problem and not seen the potential for dust mite allergens, the homeowner’s symptoms might not have been relieved even with complete and proper mold abatement.

Are mold testing kits useful?

Mold testing Kits!

Mold testing kits are advertised all over the web.  You will find that most of them are worthless.  The ones that send you a culture plate to be sat in strategic locations inside the house will give you skewed results.  More of the larger and heavier spores will fall out of the air onto the culture.  The small, more easily airborne spores are likely to be more poorly represented.  Also some molds will grow better on particular culture media than on others.  You can therefore get both false positives and false negatives.  Plus keep in mind that mold spores are virtually everywhere.  So what will this culturing effort tell you?

If you use another, possibly more effective test kit.  What do you do when you get the laboratory results back?  Unless you work in the field of microbiology, mycology or indoor air quality, you are not likely to understand the significance of the lab report. 

What I offer is something a bit different.  It is a bit more expensive, but the data will be useable.  I send you the materials with step by step instructions of how to take a sample.  You send the sample(s) back to me.  I have them analyzed by an independent laboratory and receive the lab results.  I take the lab results and generate my own report that explains the significance of the results.  If you provide photographs or other information, I will incorporate that data in with the report, discuss what this data implies and make recommendations as possible based upon the data to hand.

If you are more concerned about what might be in the settled dust that accumulates on surfaces, we can do a similar evaluation of the dust content along with instructions on how to take such samples and the significance of the findings.

Wednesday, May 31, 2017


Often “fungus” and “mold” are confusing terms as they are sometimes used interchangeably. “Fungus” is a more general term.  Fungi include molds, yeasts and macro-fungi like mushrooms, puffballs, etc. 

Water damage inside your home or office whether known or unknown can result in mold growth.  Exposure to molds particularly chronically can result in health symptoms.  Reactions can vary widely from person to person.  There are certain mold types that are commonly found due to water intrusion into building envelopes.  We will be featuring some of the most common experienced in Southern California.  Obviously these mold types are not exclusive to California, so knowing about them is worthwhile no matter whey you live.

Aspergillus – What is it?

In microscopic analysis, Aspergillus is often grouped with Penicillium.  That grouping is generally shown as Penicillium/Aspergillus or Pen/Asp.  The reason for this grouping is that the two spore types cannot be distinguished one from the other microscopically.  To differentiate the two requires seeing the underlying structure which often means culturing (or growing) the organism.

Aspergillus is found under normal conditions in soil, decaying plant debris, compost piles and stored grain. 

Indoors Aspergillus will grow on a wide variety of materials (substrates) including building materials, leather, and clothing depending on the amount of moisture present.  Aspergillus is often detected inside air conditioning systems especially on cooling coils and/or interior fiberglass liner.  On building materials Aspergillus is one of the first or primary invaders along with Penicillium.  Both can produce toxins for the purpose of discouraging other molds invading space they have already claimed.  It is speculated that some of these toxins could be harmful to humans, but this has never been clinically established. The primary invaders can be joined by a secondary invader, usually Cladosporium.  With a continuation of high levels of moisture, they can be overgrown by Stachybotrys or possibly Chaetomium.

Industrial uses include fermentation in some food and beverage production.  Some species are also used in combination with other materials to produce some drugs.  One species is able to decompose plastic.

What’s the harm?

While certain individuals can develop allergies to virtually any mold, research shows that Aspergillus species are known to cause a number of specific allergies.  Some of the more familiar health effects related to Aspergillus include asthma and hay fever.  Some allergies have names that are specific to certain professions or activities.  Some of these are:  Malt worker’s lung, Compost lung, Wood trimmers disease, Straw hypersensitivity, Farmer’s lung, Oat grain hypersensitivity.  The list is probably longer, but this should suffice as an introduction.

Some species of this mold type are quite important due to their ability to grow well at human body temperature.  All three of the ones I’m about to list can invade the body, grow where ever they manage to find a favorable environment and do damage there.

Aspergillus fumigatus will grow in the lungs resulting in fungus ball or Aspergillosis.  One of the evident symptoms is coughing up blood. 

Aspergillus flavus is known for nasal sinus lesions.

Aspergillus niger causes “Swimmer’s ear.”

It should be noted that for the most part these are “opportunistic pathogens,” meaning those with impaired immune systems are most vulnerable.  These Aspergillus species can be quite problematic in hospitals and other health care centers due to the susceptibility of patients.  When nosocomial (hospital caused) illnesses occur, testing for viable airborne Aspergillus spores should be conducted.  See my article, “Nosocomial Illnesses” at

While Stachybotrys, AKA “The Black Mold,” gets much of the publicity and is deservedly notorious, Aspergillus could be an even more important mold type due to its broader abilities to do harm.  Stachybotrys will be discussed in a future article.

What can be done about it?

The most effective way to deal with mold is to prevent water from entering the building envelope.  Given that this is impossible sometimes as leaks can occur no matter what you do, but be aware of potential roof leaks as well as leaking from plumbing fixtures.  Preventative steps should be taken, so look and take necessary action.

Also remember that exterior walls are not equipped to sustain prolonged direct impact of water.  That can break down the moisture shield causing water intrusion into wall cavities.  This can happen due to sprinkler water spraying directly onto the wall, but it can also occur due to prolonged rainy periods with wind causing impact on a particular wall. 

Once water intrusion does occur, remedies need to be applied as soon as possible.  The source of the water must be determined and eliminated at the source as possible.  Wind driven rain water regularly impacting on a wall might require a barrier to limit that impact. 

Mold contamination of gypsum wallboard should be removed by a professional mold remediation company.  The process includes isolating the affected area with plastic sheeting and putting it under negative air pressure to keep from disseminating mold spores to other parts of the building.  Workers should wear appropriate personal protective equipment.  All moldy material should be removed and disposed of.  Air scrubbing should be done to remove residual mold spores.  The interior of the remediation area should be HEPA (High Efficiency Particulate Arresting) filter vacuumed and wiped down.  It would be best to have the area professionally inspected and tested prior to removal of the containment material.

Once exposed and suffering health effects, steroids and/or anti-fungal drugs including statins are often prescribed.  Side effects of these drugs, including suppression of the immune system, can be quite troublesome.  These drugs can be very toxic, especially to the liver.


Natural remedies include probiotics that can actually enhance the immune system.  Some spices are known to be anti-fungal.  These include garlic, ginger, cayenne and goldenseal.  Starving the fungi by avoiding certain foods is also recommended.  Anti-fungal diets are found in some publications such as Breathe Free or Die – The Layman’s Guide to Mold and Other Indoor Air Quality Problems, by Stephen Huff or The Fungus Link, by Doug A. Kaufmann.


Always consult one or more health care professionals before beginning any health remedy.

Thursday, May 25, 2017

Gas Properties - Radon

Name:                         Radon

Abbreviation:  Rn

General Description:  Radon is a radioactive gas element with the atomic number of 86. It comes from the natural decay of uranium or radium that is found in nearly all soils. It typically moves up through the ground to the air above and into your home through cracks and other holes in the foundation or floors. Your home traps radon inside, where it can build up.

Odor:  Radon is a colorless, odorless and tasteless radioactive gas.

Compared to air:  Radon is considerably heavier than air so will tend to accumulate at lower levels.  It rises through the ground due to pressure relationships in that underground is more highly pressurized than above ground.

Uses:  This gas is used in cancer treatment and chemical research.  It can also be used as a tracer gas in leak detection. 

Combustible:  Radon is not a combustible gas.

Exposure Limits:  The “action level,” meaning the level that dictates that something needs to be done to reduce exposure, is generally determined to be is 4 pCi/l.  This translates into four pico curies per liter of air.  A pico curie is one trillionth of a curie.  A curie is an approximation equal to the amount of radioactivity emitted by one gram of radium-226. It is named after the French physicist, Pierre Curie.

Steve’s IAQ recommendations:  Virtually any building can have an accumulation of radon.  There are certain areas that are more likely to have radon infiltration.  In Southern California, the locations of greatest potential exposure are Ventura and Santa Barbara Counties.  No matter where you are located, it would be prudent to test your house for radon.  In California, professional testers must be certified by the state. The home owner or occupant, however, can obtain testing materials from hardware or home improvement stores and perform the testing.  Just follow the directions.  Prior to the certification to be mandated, I performed such testing so I know it is simple.  If results are above the recommended level, there are actions that can be taken.  The simplest actions would be to isolate the house from the gas that is coming up through the soil.  If there is a crawlspace, completely covering it with heavy polyethylene sheeting is one method, filling cracks in the slab if no crawlspace.  There also professionals who specialize isolating a house from radon.  Getting plenty of air change in the house will tend to neutralize the radon.  Having an outside air intake installed on your HVAC system and having the supply fan running at all times when the house is occupied is quite helpful. 

There is a saying in this business that “most houses suck;” meaning they are negatively pressurized causing them to pull in materials like gases from locations with higher pressure.  So if you don’t want your house to suck, take actions to positively pressurize it

The testing materials from your hardware store are for short-term testing; for 24 to 48 hours as I recall.  If you come up with a positive result, longer term testing can be done over 90 days or more.  This should be done by a professional.  It will give a better picture of the year-round radon exposure.

Examples:  In a house with a basement, the radon will tend to accumulate there.  Remember that Radon is much heavier than air so will remain in low spaces.  Placing an exhaust fan in the basement that runs even periodically will be helpful.  An exhaust fan in the crawlspace that keeps it negatively pressurized compared to the occupied space above will prevent most of the radon from entering the house, but should be run continually. 

Physical Effects:  Radon is the major cause of lung cancers for non-smokers causing approximately 21,000 deaths per year.  It is generally not the gas itself that causes the exposure, but small dust particles that are eradiated by the gas and are breathed into the lungs.  These are referred to as “radon progeny".  They were formerly known as “radon daughters.”  The danger of radon-related cancer is considerably increased for smokers.

How Produced:  In nature, radon is produced by the radioactive decay of radium or uranium.  The gas comes up through the soil and is dispersed unless it is trapped inside some structure like a house or other building.  It can also be present in well water.     Building materials that come from the earth, like concrete or rock can contain radon, so it is possible, but unlikely to build a radon problem into a structure.  Radon can be produced commercially by bubbling air through a radon salt solution and collecting the gas.

Tuesday, May 23, 2017

Gas Properties - H2S

Name:                         Hydrogen sulfide

Abbreviation:            H2S     

General Description:  It is a colorless gas with a very foul odor.  It is toxic to humans.  It can be deadly at sufficient quantities.  H2S is soluble in water and alcohol.

Odor:  H2S has the very unpleasant odor of rotten eggs.

Compared to air:  H2S is slightly heavier than air.  It can collect in low lying areas and enclosed spaces.  Manholes, underground vaults, sewers and other such spaces can be very dangerous due to this feature.

Combustible:  H2S is highly flammable and explosive.  When H2S burns it produces other toxic gases.  The explosive range is much higher than exposure limits.

Exposure Limits:  The National Institute for Occupational Safety and Health (NIOSH) publishes a Recommended Exposure Limit (REL) of 10 parts per million (ppm) over a 10 minute period.  OSHA put it at 50 ppm over 10 minutes.  The 8 hour limit for construction is 10 ppm with a ceiling of 20 ppm. 

Steve’s IAQ recommendations:  In an office or similar work environment, experiencing sewer odors can be quite unpleasant. The odor threshold is quite low, so unless you are in a deep basement or sub-basement, exposure to H2S is not likely to be a serious health issue.  It is often a fleeting situation and passes quickly.  Certainly if it lingers or appears often or regularly, actions should be taken to find the source and eliminate it.

Examples:  It is the trap in a drain that is filled with water by regular use that prevents sewer gas from backing up into occupied spaces.  If the trap dries out, you are likely to get an odor.  Sewer vent pipes on the roof might be too close to an outside air intake allowing sewer gas to be distributed by the air handler.  I have found uncapped sewer vent pipes inside walls and above ceilings.  H2S can also come from a damaged or broken battery.  I once chased a sewer-type odor throughout a house, crawled through the attic and was baffled until I discovered the damaged battery that powered the security system.

Physical Effects (immediate effects):  (Progressively) Odor is noticeable at around 0.1 ppm; nausea, eyes tearing, headaches (2-5 ppm); dizziness, fatigue, loss of appetite  (20 ppm); eye irritation, coughing, loss of smell, throat irritation, death in about 48 hours (100 ppm).  Higher amounts move more rapidly toward death. 

Physical Effects (lasting effects):  After a high exposure, an individual can continue to have headaches, poor memory and motor function after being removed from exposure and regaining consciousness. 

How Produced:  H2S is a by-product of a number of industries including petroleum refining, manufacturing of textiles and paper products.  It is found naturally in sewers, other areas of waste, volcanoes and oil wells, etc.