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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. The key to mold control is moisture
control. 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. Molds 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 most appropriate way to control 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 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.
- Use low air permeable insulation such as
SEALECTION®
500 to insulate walls and ceilings. Stop hot, moist air to enter
or leave the building uncontrollably through the walls.
In areas where there is a perpetual
moisture problem, do not install carpeting near drinking
fountains, 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.
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 Publications and Resources
EPA's Mold page from Asthma Web site
Floods/Flooding
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.
Federal Emergency Management Agency (FEMA):
(800) 480-2520;
www.fema.gov
mitigation website:
www.fema.gov/mit
publications on floods, flood proofing, etc.
University of Minnesota, Department of
Environmental Health & Safety -
www.dehs.umn.edu/iaq/flood.html.
"Managing Water Infiltration Into Buildings." A Systematized
Approach for Remediating Water Problems in Buildings due to Floods,
Roof Leaks, Potable Water Leaks, Sewage Backup, Steam Leaks and
Groundwater Infiltration. Questions and comments may be directed
to: Neil Carlson, M.S., CIH, Department of Environmental Health &
Safety, University of Minnesota, or Arif Quraishi, M.E., Vice
President, Special Projects, Indoor Environments Division, Institute
for Environmental Assessment, Inc.
Health and Mold
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."
Consult the Centers for Disease Control
(CDC) website.
CDC's National Center for Environmental
Health (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 the Environment" Factsheet
Stachybotrys or Stachybotrys atra (chartarum) and health effects
CDC's "Questions and Answers 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, 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 Temperature ; Recommended
Indoor Relative Humidity
|
+20 F |
35% |
| +10 F |
30% |
|
0 F |
25% |
| -10 F |
20% |
| -20 F |
15%
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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?
The EPA can guide you on Air Duct Cleaning.
Indoor Air Regulations and Mold
Threshold Limit Values (TLV's) are
guidelines (not standards) prepared by the
American Conference of Governmental industrial
Hygienists, Inc (ACGIH) to assist
industrial hygienists in making decisions regarding safe levels of
exposure to various hazards found in the workplace.
A TLV® reflects the level of exposure that
the typical worker can experience without an unreasonable risk of
disease or injury. TLVs® are not quantitative estimates of
risk at different exposure levels or by different routes of
exposure.
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