An Introduction to Mold
and Moisture
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Mansel A Nelson
I n s t i t u t e f o r Tr i b a l E n v i r o n m e n t a l P r o f e s s i o n a l s
Topics
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I.
II.
III.
IV.
V.
VI.
Overview
Indicators
Health Effects
Prevention
Investigation
Clean-up
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I. Overview
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Key information
• Types of molds
• Factors contributing to
mold growth
Types of Molds
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Under a microscope
 What are molds?
 Part of class of “biological”
contaminants that includes
bacteria, mildew, viruses,
animal dander, dust mites,
cockroaches, pollens
 Part of “Fungi” kingdom that
includes molds, yeasts,
mushrooms, rusts
 Microscopic organisms that
form and colonize through
airborne spores
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Types of Molds (continued)
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 Over 100,000 different types;
about 10 different species
common indoors
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Factors Contributing to Mold Growth
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What do molds need to grow?
Food supply
Moisture
Warm temperatures, and Oxygen
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Food Sources
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

Organic sources

Soils, food, plant matter

Human and animal hair and dander

Clothing and fabric fibers

Fibers from floor coverings, insulation, building materials
Building materials

Certain materials –particleboard, LP siding, OSB, expanded styrene,
cellulose insulation – all better food sources, absorb and hold moisture
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Moisture Sources
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 Building
envelope leaks
 Plumbing
leaks
 Damp
soil & basements
 Occupant activities
 Condensation
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Optimum Relative Humidity
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Source Health and Energy Testing Services, NE
http//www.healthandenergy.com/
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II. Indicators
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Key information
• Recognizing indicators of potential
mold infestation
• Finding sources of information
Recognizing Indicators
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1.
Known or suspected water damage
 Occupants may know of leak, flood, water
intrusion (helpful to know extent, length, actions taken)
 Visible signs of water damage – may be clearly
evident
 Less visible signs require further visual
investigation behind wallpaper, baseboards, cabinets;
in crawlspaces, on building exteriors, rust, drywall
staining
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Recognizing Indicators
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2. Reports from maintenance or custodial staff
 Know building history, repairs, structural issues
 May be first to report occupant complaints
3. Musty/mildew odors
 Indicator of mold growth; may not be visible
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Recognizing Indicators
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4. Visible mold
 Appearance of spores not only indicator
 Range of colors (all “black” molds are not toxic, though
proceed with caution)
 Growth patterns vary, depending on point of
moisture contact
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Is it Mold?
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Is it mold?
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II. Indicators
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5. Reported health problems
 Clear links allergy/respiratory
 Possible flu-like symptoms, repeated viral infections,
fatigue, frequent ER visits/hospitalizations
 NOTE: Symptoms overlap with other illnesses and
issues
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III. Health Impacts
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Key information
• Types of impacts
• Who is at most at risk
Health Impacts
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“Exposure to damp and moldy environments may cause
a variety of health effects, or none at all.”
www.CDC.gov/mold
 Health impacts vary widely and are individual in
impact.
 Health issues can result from a variety of
environmental issues and it can be difficult to
identify specific causes.
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Types of Effects
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1.
Irritant
 Exposure can irritate eyes, skin, nose, throat, and lungs, in
allergic and non-allergic individuals
 Effect is dose-related, usually transient
2.
Allergen
 Common symptoms runny nose, itchy eyes, sneezing, sore
throat, nasal congestion, eczema, dermatitis
 In high concentrations, molds can trigger symptoms in
individuals with no known allergies
 Long-term exposure can sensitize an individual, inducing
allergies and airway-reactivity
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Types of Effects (cont.)
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3.
Infectious
 Direct infection occurs when pathogens attack immune-
compromised individuals
 E.g., Aspergillus fumigatus known to cause aspergillosis
(ABPA)
4.
Toxic (rare)
 Toxic molds produce chemicals called mycotoxins
 Certain species (e.g, stachybotrus, fusarium, trichoderma) are known
carcinogens
 Mycotoxins readily absorbed by intestinal lining, airways, skin
 Presence of toxic molds usually associated with long-standing
water problem
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Who is most at risk?
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 Individuals with lower-airway diseases
 Asthma, chronic bronchitis
• Molds directly tied to presence, persistence and increased severity of
asthma episodes
 Young children (birth to age 2 – critical window)
• Allergic sensitization/genetic predisposition
• Incidence of RSV
 Elders
 Individuals with compromised immune systems
 Individuals with allergies (upper respiratory)
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IV. Prevention
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Principles for Existing Buildings
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 Work with occupants, maintenance and custodial staff to
focus on prevention practices
1. Keep it clean
2. Keep it dry
3. Keep it well ventilated
4. Keep it well maintained
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Principles for Existing Homes (cont.)
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1. Clean
Control
dust sources
Regular
Carpet
Use
cleaning
removal where possible
of walk-off mats
HEPA-filter
Reduced
vacuuming
clutter
Shoes-off
policy
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Principles for Existing Homes (cont.)
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2. Dry & Ventilated


Ventilation

Install & use exhaust fans vented to outdoors in kitchens and
bathrooms, clothes dryers–eliminate moisture that builds up from
everyday activities

Attic and crawl spaces – Keep humidity below 50% to prevent
condensation on building materials
Water damage

Thoroughly clean & dry water-damaged carpets and building
materials (within 24 hours, if possible) or

Consider removal or replacement
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Ventilation
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Necessary to remove humidity, dilute and
remove contaminants
 Bathroom

moisture condenses on cold ceiling
 Whole house ventilation

Fans, HRV/ERVs
 Kitchens
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Source Health and Energy Testing Services, NE
http//www.healthandenergy.com/
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Tips for Residents
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 Furniture 6” away from exterior walls
 Do not hang blankets on exterior walls
 Use proper window treatments and
open during the day – No blankets
 Run bath fan after each bathing event
for 30 minutes!
 Diligence – keep an eye for problem
prone areas
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V. Investigation
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Key information
• Objectives of investigation
• Types of sampling
Objectives of Investigation
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1.
Identify all moldy areas
 If occupant reports mold, search throughly (under sinks, in cabinets,
behind toilets, behind furniture; sub-floor, drywall, crawl space)
2. Identify all possible causes
 Plumbing or appliance leaks? High humidity? Condensation?
3. Reduce exposure to occupants in home/building
4. Develop plan for clean-up/remediation
5. Ensure that maintenance staff and occupant are informed
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Types of Samples
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 When is sampling necessary?

If legal action is being considered or there are serious health
impacts that require specialized medical treatment.
 Is species identification necessary?

Identifying species of mold or airborne sampling is not
recommended for investigation or remediation
 Microscope can help confirm presence of mold
 No standards for exposure levels of mold / spores
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Mold Complaints
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 A mold complaint may include some other IAQ
issues
 Consider other possibilities for IAQ concerns
 Follow air-flows
 Look for additional air pollutant sources, including
items the occupants use
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VI. Remediation / Clean-up
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First Things First
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Mold clean-up is not effective until the source of
moisture is addressed.
Mold is a moisture problem
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Remediation Guidelines
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Mold remediation discussions will continue during
IAQ courses
 Copper River
 Fairbanks
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Safety Guidelines & Resources
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 To prevent exposure and assure containment,
critical that maintenance staff employ safety
guidelines…
IICRC S520 – Standard
Guide for Professional
Mold Remediation
www.iicrc.org
Building Sciences
Corporation - RR-0210
Mold Remediation in
Occupied Homes
www.buildingscience.com
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Safety Guidelines - Occupants
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

Prevention and clean-up for small areas (cleaning non-porous
surfaces and wood with detergent; repair moisture source; dry
material, etc)
Many people use bleach, which kills mold, but
cleaning agent
Bleach is a

is not a good
strong respiratory irritant
Surfactant (soap) is better
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More Information
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General mold information
http://www.epa.gov/mold/
Mold Remediation in Schools and Commercial
Buildings
http://www.epa.gov/mold/mold_remediation.html
Mold and Moisture: Guidance for Clinicians
http://oehc.uchc.edu/CIEH.asp
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Institute for Tribal Environmental
Professionals
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Mansel A. Nelson
Senior Program Coordinator
Indoor Air Quality in Tribal Communities
Northern Arizona University (NAU)
http://www.nau.edu/iaqtc/
mansel.nelson@nau.edu
Voice 928 523 1275
FAX 928 523 1280
PO Box 5768, Flagstaff, AZ 86011
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