Introduction to Molds

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

Basic Mold Cleanup

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

Ten Things You
Should Know About Mold

• Potential health effects and symptoms associated with mold exposures includeallergic reactions, asthma, and other respiratory complaints.  

• There is no practical way to eliminate all mold and mold spores in theindoor environment; the way to control indoor mold growth is to controlmoisture.

• If mold is a problem in your home or school, you must clean up the mold andeliminate sources of moisture.

• Fix the source of the water problem or leak to prevent mold growth.

• Reduce indoor humidity (to 30-60% ) to decrease mold growth by: ventingbathrooms, dryers, and other moisture-generating sources to the outside; usingair conditioners and de-humidifiers; increasing ventilation; and using exhaustfans whenever cooking, dishwashing, and cleaning.

• Clean and dry any damp or wet building materials and furnishings within24-48 hours to prevent mold growth.

• Clean mold off hard surfaces with water and detergent, and dry completely.Absorbent materials such as ceiling tiles, that are moldy, may need to bereplaced.

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

• In areas where there is a perpetual moisture problem, do not installcarpeting (i.e., by drinking fountains, by classroom sinks, or on concretefloors with leaks or frequent condensation).

• Molds can be found almost anywhere; they can grow on virtually anysubstance, providing moisture is present. There are molds that can grow on wood,paper, carpet, and foods.

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

Asthma and Mold

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

EPA's Asthma web site

EPA's Asthma Brochure

EPA's Mold page from
Asthma web site

• Allergy & Asthma Network/Mothers of Asthmatics (AAN/MA): (800) 878-4403;www.aanma.org

• American Academy of Allergy, Asthma & Immunology (AAAAI): www.aaaai.org

• American Lung Association: 1-800-LUNG-USA (1-800-586-4872); www.lungusa.org

• Asthma & Allergy Foundation of America: (800) 7ASTHMA; www.aafa.org

• Canada Mortgage & Housing Corporation fact sheets on mold – www.cmhc-schl.gc.ca/en/burema/gesein/abhose/abhose_50.cfm

• National Institute of Allergy and Infectious Diseases: www.niaid.nih.gov

• National Jewish Medical and Research Center: (800) 222-LUNG (5864); www.njc.org

Health and Mold

How do molds affect people?

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

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

 

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

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

Consult the Centers for Disease Control (CDC) website

• CDC's National Center for EnvironmentalHealth (NCEH) has a toll-free telephone number for information and FAXs,including a list of publications: NCEH Health Line 1-888-232-6789.

• CDC's "Molds in theEnvironment" Factsheet

Stachybotrys or Stachybotrys atra (chartarum) and health effects

• CDC's "Questions andAnswers on Stachybotrys chartarum and other molds

Homes and Molds

The EPA publication, "A Brief Guide to Mold, Moisture, and Your Home" , is available here in HTML and PDF formats.  This Guide provides information and guidance for homeowners and renters on how to clean up residential mold problems and how to prevent mold growth.  A printed version will be available soon.

Biological Pollutants in Your Home

- This document explains indoor biological pollution, health effects of biological pollutants, and how to control their growth and buildup. One third to one half of all structures have damp conditions that may encourage development of pollutants such as molds and bacteria, which can cause allergic
reactions — including asthma — and spread infectious diseases.  Describes corrective measures for achieving moisture control and cleanliness.  This
brochure was prepared by the American Lung Association and the U.S. Consumer Product Safety Commission. EPA Document Reference Number 402-F-90-102, January 1990. Moisture control is the key to mold control, the Moisture Control Section from Biological Pollutants in Your Home follows:

Moisture Control

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

There are many ways to control moisture in your home:

• Fix leaks and seepage. If water is entering the house from the outside, youroptions range from simple landscaping to extensive excavation and waterproofing.(The ground should slope away from the house.) Water in the basement can resultfrom the lack of gutters or a water flow toward the house. Water leaks in pipesor around tubs and sinks can provide a place for biological pollutants to grow.

• Put a plastic cover over dirt in crawlspaces to prevent moisture from comingin from the ground. Be sure crawlspaces are well-ventilated.

• Use exhaust fans in bathrooms and kitchens to remove moisture to the outside(not into the attic). Vent your clothes dryer to the outside.

• Turn off certain appliances (such as humidifiers or kerosene heaters) if younotice moisture on windows and other surfaces.

• Use dehumidifiers and air conditioners, especially in hot, humid  climates,to reduce moisture in the air, but be sure that the appliances themselves don'tbecome sources of biological pollutants.

• Raise the temperature of cold surfaces where moisture condenses. Useinsulation or storm windows. (A storm window installed on the inside worksbetter than one installed on the outside.) Open doors between rooms (especiallydoors to closets which may be colder than the rooms) to increase circulation.Circulation carries heat to the cold surfaces. Increase air circulation by usingfans and by moving furniture from wall corners to promote air and heatcirculation. Be sure that your house has a source of fresh air and can expelexcessive moisture from the home.

• Pay special attention to carpet on concrete floors. Carpet can absorbmoisture and serve as a place for biological pollutants to grow. Use area rugswhich can be taken up and washed often. In certain climates, if carpet is to beinstalled over a concrete floor, it may be necessary to use a vapor barrier(plastic sheeting) over the concrete and cover that with sub-flooring(insulation covered with plywood) to prevent a moisture problem.

• Moisture problems and their solutions differ from one climate to another.The Northeast is cold and wet; the Southwest is hot and dry; the South is hotand wet; and the Western Mountain states are cold and dry. All of these regionscan have moisture problems. For example, evaporative coolers used in theSouthwest can encourage the growth of biological pollutants. In other hotregions, the use of air conditioners which cool the air too quickly may preventthe air conditioners from running long enough to remove excess moisture from theair. The types of construction and weatherization for the different climates canlead to different problems and solutions.

Moisture On Windows

Your humidistat is set too high if excessive moisture collects on windows and other cold surfaces. Excess humidity for a prolonged time can damage walls
especially when outdoor air temperatures are very low. Excess moisture condenses on window glass because the glass is cold. Other sources of excess moisture besides overuse of a humidifier may be long showers, running water for other uses, boiling or steaming in cooking, plants, and drying clothes indoors. A tight, energy efficient house holds more moisture inside; you may need to run a kitchen or bath ventilating fan sometimes, or open a window briefly. Storm windows and caulking around windows keep the interior glass warmer and reduce condensation of moisture there. Humidifiers are not recommended for use in buildings without proper vapor barriers because of potential damage from moisture buildup. Consult a building contractor to determine the adequacy of the vapor barrier in your house. Use a humidity indicator to measure the relative humidity in your house. The American
Society of Heating and Air Conditioning Engineers (ASHRAE) recommends these maximum indoor humidity levels.

 

Outdoor Recommended Indoor Temperature Relative Humidity:

+20 F. 35%
+10 F. 30%
0 F. 25%
-10 F. 20%
-20 F. 15%

 

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

Should You Have the Air Ducts in Your Home Cleaned?

- excerpt on duct cleaning and mold follows, please review the entire document for additional information on duct cleaning and mold.

You should consider having the air ducts in your home cleaned if:

There is substantial visible mold growth inside hard surface (e.g., sheet metal) ducts or on other components of your heating and cooling system. There
are several important points to understand concerning mold detection in heating and cooling systems:

• Many sections of your heating and cooling system may not be accessible for avisible inspection, so ask the service provider to show you any mold they sayexists.

• You should be aware that although a substance may look like mold, a positivedetermination of whether it is mold or not can be made only by an expert and mayrequire laboratory analysis for final confirmation.  For about $50, somemicrobiology laboratories can tell you whether a sample sent to them on a clearstrip of sticky household tape is mold or simply a substance that resembles it.

• If you have insulated air ducts and the insulation gets wet or moldy itcannot be effectively cleaned and should be removed and replaced.

• If the conditions causing the mold growth in the first place are notcorrected, mold growth will recur.