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 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 .
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
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
Stachybotrys or Stachybotrys atra (chartarum)
and health effects
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 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.
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