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THE FOLLOWING INFORMATION IS
AVAILABLE FROM THE ENVIROMENTAL
PROTECTION AGENCY AT www.epa.gov .
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.
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.
- Potential health effects and symptoms associated with mold exposures
include allergic reactions, asthma, and other respiratory complaints.
- 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.
- If mold is a problem in your home or school, you must clean up the mold
and eliminate 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: venting
bathrooms, dryers, and other moisture-generating sources to the outside; using
air conditioners and de-humidifiers; increasing ventilation; and using exhaust
fans whenever cooking, dishwashing, and cleaning.
- Clean and dry any damp or wet building materials and furnishings within
24-48 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 be
replaced.
- 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 install
carpeting (i.e., by drinking fountains, by classroom sinks, or on concrete
floors with leaks or frequent condensation).
- Molds can be found almost anywhere; they can grow on virtually any
substance, 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.
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
Mold growth may be a problem after flooding. EPA's Fact Sheet:
Flood Cleanup: Avoiding
Indoor Air Quality Problems - discusses steps to take when cleaning and
repairing a home after flooding. Excess moisture in the home is cause for
concern about indoor air quality primarily because it provides breeding
conditions for microorganisms. This fact sheet provides tips to avoid
creating indoor air quality problems during cleanup. U.S. EPA, EPA Document
Number 402-F-93-005, August 1993.
Molds can trigger asthma episodes in sensitive individuals with asthma (See
Asthma Section above); molds can also trigger
allergies in sensitive individuals.
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."
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,
your options range from simple landscaping to extensive excavation and
waterproofing. (The ground should slope away from the house.) Water in the
basement can result from the lack of gutters or a water flow toward the
house. Water leaks in pipes or 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
coming in 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
you notice 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't become sources of biological pollutants. |
| Raise the temperature of cold surfaces where moisture condenses. Use
insulation or storm windows. (A storm window installed on the inside works
better than one installed on the outside.) Open doors between rooms
(especially doors to closets which may be colder than the rooms) to increase
circulation. Circulation carries heat to the cold surfaces. Increase air
circulation by using fans and by moving furniture from wall corners to
promote air and heat circulation. Be sure that your house has a source of
fresh air and can expel excessive moisture from the home. |
| Pay special attention to carpet on concrete floors. Carpet can absorb
moisture and serve as a place for biological pollutants to grow. Use area
rugs which can be taken up and washed often. In certain climates, if carpet
is to be installed 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 hot and wet; and the Western Mountain states are cold and dry. All
of these regions can have moisture problems. For example, evaporative
coolers used in the Southwest can encourage the growth of biological
pollutants. In other hot regions, the use of air conditioners which cool the
air too quickly may prevent the air conditioners from running long enough to
remove excess moisture from the air. The types of construction and
weatherization for the different climates can lead 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 a visible inspection, so ask the service provider to show you any mold
they say exists. |
| You should be aware that although a substance may look like mold, a
positive determination of whether it is mold or not can be made only by an
expert and may require laboratory analysis for final confirmation. For
about $50, some microbiology laboratories can tell you whether a sample sent
to them on a clear strip 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 it
cannot be effectively cleaned and should be removed and replaced. |
| If the conditions causing the mold growth in the first place are not
corrected, mold growth will recur. |
Standards or Threshold Limit Values (TLVs) for airborne concentrations of
mold, or mold spores, have not been set. Currently, there are no EPA
regulations or standards for airborne mold contaminants.
EPA has a number of resources available, you can start with the Indoor Air
Quality Building Evaluation and Assessment Model (I-BEAM). I-BEAM updates and
expands EPA's existing Building Air Quality guidance and is designed to be
comprehensive state-of-the-art guidance for managing IAQ in commercial
buildings. This guidance was designed to be used by building professionals
and others interested in indoor air quality in commercial buildings. I-BEAM
contains text, animation/visual, and interactive/calculation components that
can be used to perform a number of diverse tasks. See
www.epa.gov/iaq/largebldgs/ibeam_page.htm
See also "Building
Air Quality: A Guide for Building Owners and Facility Managers" and the
"Building Air
Quality Action Plan"
Excerpt from the
Building Air Quality:
A Guide for Building Owners and Facility Managers,
Appendix C -
Moisture, Mold and Mildew:
How to Identify the Cause of a Mold and Mildew Problem.
Mold and mildew are commonly found on the exterior wall surfaces of
corner rooms in heating climate locations. An exposed corner room is likely
to be significantly colder than adjoining rooms, so that it has a higher
relative humidity (RH) than other rooms at the same water vapor pressure.
If mold and mildew growth are found in a corner room, then relative humidity
next to the room surfaces is above 70%. However, is the RH above 70% at the
surfaces because the room is too cold or because there is too much moisture
present (high water vapor pressure)?
The amount of moisture in the room can be estimated by measuring both
temperature and RH at the same location and at the same time. Suppose there
are two cases. In the first case, assume that the RH is 30% and the
temperature is 70oF in the middle of the room. The low RH at
that temperature indicates that the water vapor pressure (or absolute
humidity) is low. The high surface RH is probably due to room surfaces that
are "too cold." Temperature is the dominating factor, and control
strategies should involve increasing the temperature at cold room surfaces.
In the second case, assume that the RH is 50% and the temperature is 70oF
in the middle of the room. The higher RH at that temperature indicates that
the water vapor pressure is high and there is a relatively large amount of
moisture in the air. The high surface RH is probably due to air that is
"too moist." Humidity is the dominating factor, and control strategies
should involve decreasing the moisture content of the indoor air.
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