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MOLD: A COMPLETE GUIDE to TEST CLEAN PREVENT
AIR CLEANER PURIFIER TYPES
AIR FILTERS for HVAC SYSTEMS
AIR POLLUTANTS, COMMON INDOOR
AIR QUALITY IMPROVEMENT STRATEGIES
ALLERGEN TESTS for BUILDINGS
ANIMAL ALLERGENS / PET DANDER
ANIMAL or URINE ODOR SOURCE DETECTION S
ATTORNEYS and EXPERT WITNESSES
BIBLIOGAPHY ENVIRONMENTAL HEALTH, MOLD, IAQ
CAR MOLD CONTAMINATION
CARPET DUST IDENTIFICATION
CARPET MOLD CONTAMINATION
CAT DANDER in BUILDINGS
COMBUSTION GASES & PARTICLE HAZARDS
CONDENSATION or SWEATING PIPES, TANKS
CPSC Indoor Air Pollution Book Online Copy
DUCT SYSTEM & DUCT DEFECTS
EMERGENCY RESPONSE, IAQ, GAS, MOLD
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
FLOODS IN BUILDINGS-mold
GAS EXPOSURE EFFECTS, TOXIC
HUMIDITY CONTROL & TARGETS INDOORS
HOUSE DUST ANALYSIS
HOUSE DUST COMPONENTS
INDOOR AIR QUALITY IMPROVEMENT GUIDE
MILDEW REMOVAL & PREVENTION
MOISTURE CONTROL in BUILDINGS
MOLD GROWTH on SURFACES, TABLE OF
MYCOPHOBIA, STAINS MISTAKEN for MOLD
NOISE / SOUND DIAGNOSIS & CURE
ODORS GASES SMELLS, DIAGNOSIS & CURES
OZONE for MOLD OR ODORS
RADON HAZARD TESTS & MITIGATION
SAFETY HAZARDS GUIDE
SICK HOUSE IAQ QUESTIONNAIRE
SMELL PATCH TEST to Track Down Odors
STAIN DIAGNOSIS on BUILDING INTERIORS
VENTILATION in BUILDINGS
Light colored toxic or allergenic mold contamination: this article explains how to find and test for light or hard-to-see mold growth on building surfaces. The photo at page top shows a hard-to-see light-colored (possibly toxic) mold on the surface of an interior door. It is easy to miss large areas of light colored mold like this unless a careful inspection is made and careful use of light is applied.
Too many "mold inspectors" are quick to test the obvious "black molds" found on building surfaces while they may fail to find and identify possibly more harmful mold species simply because they ignored the light-colored mold growth. This document describes how to find mold and test for mold in buildings, including how and where to collect mold samples using adhesive tape - an easy, inexpensive, low-tech but very effective mold testing method.
This procedure helps identify the presence of or locate the probable sources of mold reservoirs in buildings, and helps decide which of these need more invasive, exhaustive inspection and testing.
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Other mold species are light in color or nearly invisible when growing on an interior surface unless you look carefully. This desk sat in a wet basement for only two months yet it was rapidly covered with a toxic mold, Aspergillus niger. Aspergillus molds indoors can be difficult to see.
A. niger spores are tiny and are easily made airborne by the smallest disturbance. The basement housing this moldy chest had Aspergillus levels in air enormously higher than the outdoor sample.
Aspergillus mold growth on furniture
We find as much or more Penicillium/Aspergillus in houses than Stachybotrys, but these light green, gray or tan mold colonies are more difficult to see if you don't know how to look.
To check more carefully and thus more successfully for mold, shine your flashlight along the wall surface in an area that has been damp or wet.
Don't shine it right at the wall or you won't see much. Look where things have been wet or damp, regardless of whether it was a single event (washer flood) or one that happens at every rainstorm.
Keep in mind that different molds like different moisture, temperature, and food.
Watch out: One reason that S. chartarum has been "over-reported" as a problem in some studies is that the field "experts" didn't look for lighter molds, and maybe they didn't even carry a flash light. The photo here shows three tape samples being taken from different heights on a laundry room wall.
Three different mold species were found, one in each area. Only the lowest black mold was obvious.
In this wall test of three molds which were growing quite close together, I've marked each tape sample so that you can see where it was on the wall. #1 =Stachybotrys chartarum, #2 = Ulocladium chartarum, #3 = Aspergillus sp.. - it is this third mold which, in a larger quantity, would be airborne and more likely to bother building occupants. Yet nearly 100% of home owners and 80% of industrial hygienists and 90% of home inspectors who send mold samples to our lab are going to tape-sample only the "dark mold" on this wall.
Why are there three different genera/species on this drywall? Most likely because each of them prefers a different moisture level in the paper which they're digesting. I can generally track the mold genera up the wall as a function of the moisture gradients in the wall. When a wall has been wet because of wet floor conditions, the drywall and in-cavity wall insulation will be wettest at the wall bottom.
At MOLD LEVEL REPORTING we explain the errors you can expect if you do not choose a properly-representative area of a surface when collecting mold or dust samples and at MOISTURE GRADIENTS & MOLD we explain why we find different mold genera/species at different locations on moldy drywall.
Be sure to review our notes above on use of lighting at Use of a flashlight to find mold since if you don't know exactly how to use a flashlight, as simple as it seems, you're not going to find important light-colored molds in buildings.
Photo of light-colored mold inside of a Florida air conditioning air handler unit above, courtesy of Mark Cramer, Tampa.
Also see MOLD in BUILDINGS and see MOLD GROWTH on SURFACES for an index of what mold genera/species are frequently found on various building surfaces and materials, and see MOLD RELATED ILLNESS SYMPTOMS and finally, for an atlas of building molds and for more microphotographs of building mold samples observed in our laboratory, see MOLD ATLAS & PARTICLES INDEX.
See HIDDEN MOLD in OTHER PLACES for details of this and other places to look for hidden mold in buildings.
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Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.
Guidelines defining what's a "large amount" of mold and what's reasonable for a homeowner to handle have been published by several states including New York and California.
People who are allergic, asthmatic, infant, elderly, immune-impaired, etc., should not disturb mold and should not be in the area where mold remediation is being performed. Consult with your doctor, health department or other professional before tackling this job yourself.
Mold Contamination Testing, Cleanup, Prevention: references & products
OTHER IAQ ISSUES: How To Find and Address Other Indoor Air or Indoor Environment Contaminants Besides Mold
Mold or allergens may not be the only or even the main indoor environmental contaminant. Don't let media attention to mold cause so much enviro-scare fear that other, possibly more urgent hazards go un-addressed.