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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.
Molds can trigger asthma episodes in sensitive individuals with asthma.
People with asthma should avoid contact with or exposure to molds.
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
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)
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
Moisture control is the key to mold control, the Moisture Control Section
from Biological Pollutants
in Your Home follows:
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:
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: