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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. 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.
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.
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
Stachybotrys
or Stachybotrys atra (chartarum) and health effects
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. |
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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. |
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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 "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.
The Agency's premier resource on this issue is the Indoor
Air Quality Tools for Schools kit. Our schools-related resources on
the web start at: epa.gov/iaq/schools.
The asthma companion piece for the IAQ Tools for Schools
kit, titled Managing Asthma in the School Environment (epa.gov/iaq/schools/asthma)
has been recently published. This publication has a section entitled Clean
Up Mold and Moisture Control at: epa.gov/iaq/schools/asthma/eat-cumcm.htm
Excerpt from IAQ
Tools for Schools kit companion piece, Managing
Asthma in the School Environment:
Common Moisture Sources Found in Schools
Moisture problems in school buildings can be caused by a
variety of conditions, including roof and plumbing leaks, condensation, and
excess humidity. Some moisture problems in schools have been linked to changes
in building construction practices during the past twenty to thirty years.
These changes have resulted in more tightly sealed buildings that may not
allow moisture to escape easily. Moisture problems in schools are also
associated with delayed maintenance or insufficient maintenance, due to budget
and other constraints. Temporary structures in schools, such as trailers and
portable classrooms, have frequently been associated with moisture and mold
problems.
Suggestions for Reducing Mold Growth in Schools
Reduce Indoor Humidity:
| Vent showers and other moisture-generating sources to the
outside.
| Control humidity levels and dampness by using air
conditioners and de-humidifiers.
| Provide adequate ventilation to maintain indoor humidity
levels between 30-60%.
| Use exhaust fans whenever cooking, dishwashing, and
cleaning in food service areas. |
| | |
Inspect the building for signs of mold, moisture, leaks, or
spills:
| Check for moldy odors.
| Look for water stains or discoloration on the ceiling,
walls, floors, and window sills.
| Look around and under sinks for standing water, water
stains, or mold.
| Inspect bathrooms for standing water, water stains, or
mold.
| Do not let water stand in air conditioning or
refrigerator drip pans. |
| | | |
Respond promptly when you see signs of moisture and/or mold,
or when leaks or spills occur:
| Clean and dry any damp or wet building materials and
furnishings within 24-48 hours of occurrence to prevent mold growth.
| Fix the source of the water problem or leak 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.
| Check the mechanical room and roof for unsanitary
conditions, leaks, or spills. |
| | | |
Prevent moisture condensation:
| Reduce the potential for condensation on cold surfaces
(i.e., windows, piping, exterior walls, roof, or floors) by adding
insulation. |
Floor and carpet cleaning:
| Remove spots and stains immediately, using the flooring
manufacturer’s recommended techniques.
| Use care to prevent excess moisture or cleaning residue
accumulation and ensure that cleaned areas are dried quickly.
| 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). |
| |
U.S. Environmental Protection Agency (EPA), Indoor
Environments Division (IED)
An Office Building Occupant's Guide to IAQ - epa.gov/iaq/pubs/occupgd.html
Biological Contaminants - epa.gov/iaq/pubs/bio_1.html
Building Air Quality Action Plan (for Commercial Buildings)
- epa.gov/iaq/largebldgs/actionpl.html
Floods/Flooding - epa.gov/iaq/pubs/flood.html
Mold Remediation in Schools and Commercial Buildings - epa.gov/iaq/molds/mold_remediation.html
For more subject-specific links, go to: epa.gov/iaq/schools/links.html,
or epa.gov/iaq/asthma/links.html,
or epa.gov/iaq/moreinfo.html.
U.S. EPA
EPA's Antimicrobial
Information Hotline
(703) 308-0127/(703) 308-6467
email: Info_Antimicrobial@epa.gov
The Antimicrobials Information Hotline provides direct
answers to questions concerning current antimicrobial issues. Please call
during normal business hours (Monday - Friday 9 a.m. to 5 p.m.) or leave a
message after hours. The information provided can cover issues relevant to any
or all antimicrobial pesticides including health & safety issues,
registration and re-registration issues, as well as information on pesticide
laws, rules, and regulations relating to antimicrobials.
Other Links
The following list of resources includes information created
and maintained by other public and private organizations. The U.S. EPA does not
control or guarantee the accuracy, relevance, timeliness, or completeness of
this outside information. Further, the inclusion of such resources is not
intended to endorse any views expressed or products or services offered by the
author of the reference or the organization operating the service on which the
reference is maintained.
American College of Occupational and Environmental Medicine
(ACOEM)
(847) 818-1800 www.acoemprivatepractice.com
Referrals to physicians who have experience with environmental exposures.
American Conference of Governmental Industrial Hygienists,
Inc. (ACGIH)
(513) 742-2020 www.acgih.org
Occupational and environmental health and safety information
American Industrial Hygiene Association (AIHA)
(703) 849-8888 www.aiha.org
Information on industrial hygiene and indoor air quality issues including mold
hazards and legal issues
American Society of Heating, Refrigerating, and
Air-Conditioning Engineers, Inc. (ASHRAE)
(800) 527-4723 www.ashrae.org
Information on engineering issues and indoor air quality
Association of Occupational and Environmental Clinics (AOEC)
(202) 347-4976 www.aoec.org
Referrals to clinics with physicians who have experience with environmental
exposures, including exposure to mold; maintains a database of occupational
and environmental cases
Association of Specialists in Cleaning and Restoration (ASCR)
(800) 272-7012 www.ascr.org
Disaster recovery, water and fire damage, emergency tips, referrals to
professionals
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