A three part series on molds, allergens, and respiratory irritants

What You Need to Know About Molds, Allergens, and Respiratory Irritants
Testing Your Home for Molds, Allergens, and Respiratory Irritants
Clearing the Air: Protecting Your Home from Molds, Allergens, and Respiratory Irritants

Part 1:
What You Need to Know About Molds, Allergens, and Respiratory Irritants

Concern about indoor exposure to molds, allergens, and other respiratory irritants has been increasing as the public becomes more aware that exposure to these airborne particles and chemicals may cause a variety of health effects and symptoms, including allergic reactions, asthma, fatigue, respiratory congestion and cough, runny nose, eye irritation, and cough.

This series of articles presents current scientific information that may help you better understand the problem and answer questions that are important to you.

Molds (fungus, yeast) can be found almost everywhere. Mildew is another name for certain types of molds, such as Penicillium and Aspergillus. Mold and mildew can grow on almost any food source, as long as moisture and air are present. Food used by many molds includes wood, paper, carpet, bread, fruits, and home insulation material. Only when excessive moisture accumulates in homes, buildings, or on building materials will mold growth occur. This is especially true when the moisture problem or water leak (also known as water intrusion) remains undiscovered or is not repaired. Even though it is impossible to eliminate all molds and mold spores from the indoor environment, mold growth can be effectively controlled indoors by controlling moisture or water intrusion indoors.

Most molds have the ability to survive in one of two forms. The hyphae or stalk form exists when the mold has plenty of food and water. When the food and water are less plentiful, the mold will produce another form (spores) to help insure its survival. Spores are much like plant seeds; they will only grow when food and water are once again available. Mold spores are generally what become airborne in a home. Spores are designed to be picked up by air currents, fabrics, pets, and people. When spores that get transported in this fashion are deposited on a wet area they germinate or sporulate. Sporulation results in the growth of the hyphae form. It’s a cycle . . . plenty of food and water equals hyphae; limited food and water equals spores. Food and water are the keys to mold growth and survival. When proper food and water conditions exist, molds can grow fairly rapidly and produce very large colonies or areas of contamination. These colonies contain a mixture of both the hyphae and spore forms of the mold.

Molds reproduce by making these spores that are only visible with a microscope. Mold spores waft through the indoor (and outdoor) air continually. When mold spores land on a damp spot indoors, they begin growing and digesting whatever they are growing on in order to survive. Molds gradually destroy the things they grow on.

Many types of molds exist. All molds have the potential to cause health effects. Molds can produce allergens that can trigger allergic reactions and even asthma attacks in people allergic to molds. Alternaria and Cladosporium are two common molds that are frequently associated with mold allergies. Rhizopus, Aspergillus, Mucor and Penicillium are other naturally occurring molds that are associated with allergies. In people allergic to molds, exposure to low levels of mold spores and hyphae can cause allergic reactions.

Some molds are known to produce toxins and /or irritants. These toxins or irritants, frequently referred to as mycotoxins, are produced as a part of the molds natural metabolism. Some species of Aspergillus, Penicillium, Fusarium, Trichoderma, Memnoniella, and Stachybotrys can produce mycotoxins. Other species of this same group may not produce mycotoxins. Unlike allergy patients, people generally must be exposed to high numbers of toxin-producing spores over an extended period of time in order for human toxicity to develop. Although there is evidence documenting severe health effects of mycotoxins and molds in humans, most of this evidence is derived from ingestion of contaminated foods (i.e., grain and peanut products) or occupational exposures in agricultural settings where inhalation exposures are very high.

Allergens are a special class of substances (particles and chemicals) that can cause an allergenic response in susceptible people. Common allergens include tree, grass, and weed pollens, airborne mold spores, housedust, dust mites, animal dander (skin and hair flakes; especially from cats, dogs, and birds), foods, and cockroaches. There are more than 400 reported allergens; ranging from ragweed and grass pollens to extracts of tobacco smoke, cotton, and soft drinks.

Irritants are typically chemical substances that cause irritation and inflammation of the respiratory tract. Included in this category is nitrogen dioxide (produced when cooking foods), pesticides, plasticizers used in building materials, volatile organic compounds (VOCs-example: formaldehyde), fragrances, and environmental tobacco smoke (ETS).

Molds, allergens, and irritants all have the ability to trigger asthma attacks in susceptible individuals. Because the asthma mortality rate has doubled in the United States since the 1970’s, many authorities in medicine, science, business, and government are trying to identify factors in the environment that have created this increase. Part 2 of this series will address the issue of Testing Your Home for Molds, Allergens, and Respiratory Irritants.

People with asthma react to allergens and irritants differently than people who do not have asthma. These people respond to allergens and irritants that don’t affect the airways in normal lungs. Many things can trigger the narrowing of the airways in people with asthma, such as pollens, molds, dust mites, animal dander (skin cells and fragments), smoke, cold air and exercise. In an asthma attack, a person must exert more effort to move air in and out because the smooth muscles of the airways go into a spasm. The cells and tissues lining the airways swell and mucus is secreted into the airway. This makes breathing more difficult and causes the characteristic wheezing many asthma patients experience.

Because no one knows for sure what causes asthma, determining what triggers a person’s asthma attack is usually difficult. Allergy skin testing, blood tests, or simply noting those things that trigger an attack are the most frequently used methods for trying to pinpoint the cause of asthma.

Avoiding Common Causes of Asthma Attacks

Common indoor allergens are house dust mites, feathers, cockroaches and cockroach feces, animal dander, and molds. Anything that can be done to reduce exposure to these allergens reduces the number and severity of attacks. Removing wall-to-wall carpets, maintaining indoor humidity below 55%, and using special pillow and mattress covers can reduce exposure to mites. Cats and dogs must be removed to significantly decrease animal dander and saliva. Irritants such as cigarette smoke, candle fumes, and high dust levels should also be avoided. Tartrazine, a yellow coloring used in drugs and foods may also cause attacks. The food preservative additive - sulfites - may trigger attacks after a susceptible person eats from a salad bar or drinks beer or red wine.

Part 2:
Testing Your Home for Molds, Allergens, and Other Irritants

Is testing for molds, allergens, and other irritants necessary? In specific instances, such as cases where the source of the mold contamination is unclear, or health concerns are a problem, or where litigation is involved, you may consider testing as part of the overall evaluation.

Testing should be done only after developing a sampling plan that includes information or concerns regarding suspected mold, allergen, or irritant sources. It is important to figure out what you think is happening and how to prove or disprove it before you test. If you do not have extensive experience and/or are in doubt about testing, consult an experienced professional. This individual can help you decide if testing is useful or needed, and will be able to conduct cost-effective and meaningful sampling and testing. Testing often helps locate the source of mold contamination, identify some of the molds, allergens, and irritants present, and differentiate between mold and other particulates present (soot, dust, fibers, insects, etc)

Two of the most common tests performed by professional environmental scientists are the sticky tape or Scotch tape test and the particle trap test.

When mold, allergen, or other irritant contamination is suspected on a surface, the simplest and most inexpensive method to confirm the presence of these contaminants is by sticky tape or Scotch tape sampling. A piece of Scotch tape 1”-2” long is taken from the dispenser and lightly pressed against the contaminated surface. The tape is then pressed against a clean, lint-free microscope slide; the slide is identified, and then sent to a qualified laboratory for microscopic examination. Upon examination, mold spores, mold fragments (hyphae), insect feces and body parts, skin cells (dander), dust, plant pollen, plant materials, dust mites, fibers, and other known allergens can be identified and quantified. This information becomes very valuable when compared to health concerns that are frequently associated with contaminated surfaces and sticky tape testing. Typically, a sticky tape report will include a rough estimate of the numbers and kinds of molds present on the area sampled. For example, 4+ Penicillium sp. means that a very high number of Penicillium sp. mold was present at the time of sampling. 3+ Debris means that a moderate to high level of dust, soot, insect parts, fibers etc. was present.

The particle trap test is specifically designed for the rapid collection and testing of airborne aerosols including mold spores, pollen, insect parts, skin cell fragments, fibers, and inorganic particles. This test is most useful for indoor air quality testing, allergy testing, and flood restoration monitoring. Particle trap testing has the added advantages of being able to collect and quantify particles from very large volumes of air. This feature is especially important when comparing mold spore counts that were collected from various locations (inside vs. outside). Particle trap testing requires specialized equipment and is best when performed by qualified professionals.

Interpretation of test results can be one of the most complex and tedious aspects of mold, allergen, and irritant testing. Since no EPA or other Federal threshold limits have been set for mold spores or mold, testing cannot be used to check a building’s compliance with Federal mold standards. Homeowners may conduct simplified sticky tape testing. Sampling and testing for mold, allergens and other irritants should be conducted by professionals with specific experience in designing sampling protocols, sampling methods, and interpretation of results.

Other air quality testing that is available includes tests for carbon monoxide, carbon dioxide, total particles, volatile organic compounds (VOCs), relative humidity, temperature, and moisture levels.

Testing for mold, allergens, and other irritants plays an important role in determining the existence and extent of an indoor air quality problem. The data and information gained from a thoughtful and scientifically valid testing program helps define the problem and begins to establish a rational and common sense approach to mold, allergen, and irritant problem-resolution.

Part 3:
Cleanup and Protecting Your Home from Molds, Allergens, and Irritants

Molds, allergens, and irritants include bacteria, molds, mildew, viruses, animal dander, cat saliva, house dust mites, cockroaches, and pollen. There are many sources of these pollutants. Pollens originate from plants; people and animals transmit viruses; people, animals, and soil and plant debris carry bacteria; and household pets are sources of saliva and animal dander. The protein in urine from mice and rats is a potent allergen. When it dries, it can become airborne. Contaminated air handling systems can become breeding grounds for mold, mildew, and other sources of biological contaminants and can then distribute these contaminants through the house.

By controlling the relative humidity level in the home, the growth of some sources of problems can be reduced. A relative humidity of less than 50% is generally satisfactory for homes. Widely available humidity monitors (Cost $20-50) are useful in checking the humidity level in your home. Standing water, water damaged materials, or wet surfaces also serve as a breeding ground for molds, mildews, bacteria, and insects. House dust mites, the source of very powerful allergens, grow in damp, warm environments.

Reducing Exposure to Biological Contaminants

Within 24-48 hours thoroughly clean and dry water damaged carpets and building materials. Water damaged carpet and padding usually must be replaced. It is virtually impossible to adequately dry these materials and rid them of contaminants. Wallboard (sheetrock) must be dried completely. The paper covering on wallboard serves as an ideal food source for all types of mold and mildew. The combination of water and paper is the perfect diet for these organisms.
Ventilate the attic and crawl spaces to prevent moisture buildup. Condensation is another form of moisture and supports mold and mildew growth.
Install and use exhaust fans that are vented to the outside in the kitchen and bathrooms and vent clothes dryers outdoors. These actions can eliminate much of the moisture that builds up from everyday activities.
Clean and maintain cool mist or ultrasonic humidifiers. Improperly maintained these devices become breeding grounds for all manner of molds, allergens and irritants.
Keep the house clean. House dust mites, pollens, animal dander, molds, and other allergy-causing agents and irritants can be reduced, but not eliminated, through regular cleaning. Using a HEPA vacuum cleaner is also a good idea. These vacuum cleaners are widely available and minimize the discharge of dust and debris back into the air.
Regularly clean and disinfect floor drains.
Regularly inspect for and repair all sources of water intrusion or leaks. Because water is a key element to mold growth, it is essential that water problems be fixed immediately.

General Mold-Cleanup Procedures

Identify and correct the moisture source
Clean, disinfect, and dry moldy area. An effective disinfectant is a bleach solution prepared by adding 1 cup of household bleach to 1 gallon of tap water. Prepare this solution daily.
Bag and dispose of any material that has mold-growth potential, such as rags, paper, leaves, debris. Molds love cellulose/paper products. Moldy material can be disposed of just like other household garbage.
The homeowner, using the accepted guidelines published by the Environmental Protection Agency (www.epa.gov) and other public health administrations can perform most mold-cleanup. When in doubt, contact Nova Biologicals, Inc at 936-756-5333 for a review of your problem and a common-sense approach to resolving your problem. Note: There may be potential health hazards related to mold remediation, especially for the very young, the very old, and the immune compromised.

Cleaning Air Ducts

Air ducts can become contaminated with mold and other substances and you should consider air duct cleaning if (1) there is substantial visible mold growth inside the hard surface ducts or on other components of your heating and cooling system; (2) ducts are infested with vermin (rodents, insects); (3) ducts are clogged with excessive amounts of dust and debris and/or particles are actually released into the home from your supply registers. Successful duct cleaning depends on many factors. Contact your heating and air conditioning service provider for their recommendations.

Musty Odor Still There?

Continue to dry out wet areas and search for any hidden areas of mold. If the area continues to smell musty, you may have to clean it again. Wall cavities, water damaged furniture, plumbing closets may be suspected areas of mold growth. Continue to dry and ventilate the area. Don’t replace flooring or begin rebuilding until the water-damaged area is dried completely.

Nova's testing and evaluation services can help you determine the quality of the air you breathe.