FAQs on How to use a black light or UV light.

This article series describes uses of UV light in building investigations. We describe the use of a black light, UV light to screen buildings for pet urine or urine from humans or other animals even where no stains are visible in or around buildings.

FAQs on Using Ultra Violet Light (UV light or "black light") for Forensic Investigation

These questions & answers about how to make effective use of UV light or "black light" in building or environmental investigations were posted originally at UV LIGHT BLACK LIGHT USES - you will enjoy reviewing that information.

On 2019-02-27 by (mod) - killing mold in your house using a UV flashlight.

Sandra

Thank you for an interesting question and an interesting idea of killing mold in your house using a UV flashlight.

Unfortunately the Greeks killed people like me for bringing bad news.

But the truth is that you can't effectively kill all of the mold using the UV light that you describe.

Furthermore even if you could kill the mold you would be leaving a health risk in place because some mold spores are still toxic or allergenic even when they are no longer viable.

What this means is that you need to remove the mold and fix the sources of moisture or leaks that caused its growth. Some materials like moldy drywall cannot be cleaned they have to be replaced.

On 2019-02-27 by Sandra

I have discovered white and brown mold growing extensively in various areas of my old house after this very wet year. I had an idea that maybe I could kill it with UV light and bought a small "UV" flashlight at the local hardware store ($10). When I shine it at the brown mold it seems to look yellow. When I shine it at the white mold the mold turns a deep fluorescent-looking purple.

I shone the light on the wallpaper on the walls in this room and the wallpaper seems to have lots of purple on it also. Can you tell me anything about what kind of mold this purple stuff might be?

My baby grand piano is full of it. (SOB) The brown stuff has gotten all over the mattes and backing papers of many framed watercolors that I was storing in this room. Can I treat either or these molds with UV light and or H2O2/vinegar?

On 2019-02-12 by (mod) -

Sue

Blue fibers? What fibers are normally found in buildings? Can you really use "black light" to screen a building for mold or other harmful substances?

No.

Unfortunately, because so many materials will flouresce under UV light, you can not use black light alone to identify particulate fibers or particulate hazards in buildings. The mistake here isn't with the light you bought on Amazon but rather the purpose for which the light was used.

Your dominant fibers might be blue or they may simply look blue because you're illuminating them with UV light which gives a blue cast to many particles that fluoresce.

Fibers are the most-common component in indoor building dust in most environments and are normally explained by the most-common fabric fiber sources in buildings:

Carpets and rugs,

Draperies, curtains, table cloths, towels

Bedlinens, blankets, covers

Clothing

and common but normally only at low levels,

fiberglass

plant fibers and hairs

and often present as a "fiber" hairs from humans and animals also normally at lower levels.

Along with fibers in house dust where there are human occupants are skin cells.

Normally at much lower levels are settled mold spores that arrived in outdoor air.

Please see details about the components in normal and abnormal indoor dust

at HOUSE DUST COMPONENTS at https://inspectapedia.com/sickhouse/House_Dust_Composition.php

However microscopic examination of indoor dust samples that are representative of indoor conditions can be informative.

An experienced forensic lab or environmental lab technician can quickly and easily recognize most particles found in indoor dust, and with more sophisticated methods can identify just about all particles. (There are a few such as basidiospores, a generic small round colorless mold spore) that can be difficult to identify to genera species of mold, not that that usually is necessary).

Then the technician can report on abnormal conditions such as

- a dominant or highly-frequent presence of unusual particles. For example insulation fiberglass that was tracked in to the living area, or mold spores, or animal dander, or dust mite and insect fragments at high levels, or other allergens or irritants.

- even occasional occurrences of certain special "particles" such as even a few Aspergillus sp. mold spores found in chains - an indication of active mold growth nearby. Since those particular mold spor chains are so fragile that they quickly break up as the move through air we know that if we see spore chains indoors they didn't travel far so we figure there may be a nearby mold contamination source.

UV or "black light" is fun to fool with and particularly useful to spot otherwise hard to see animal urine or some other indoor substances but it is not and cannot be used successfully as you describe and is essentially useless as a sole-dependent indoor mold contamination investigation tool.

If you are worried about an indoor mold contamination problem in your home and you don't already see the problem with the naked eye,

see the suggestions and procedures at

HIDDEN MOLD, HOW TO FIND https://inspectapedia.com/mold/Find-Hidden-Mold.php

which includes as a SUB-TOPIC USING LIGHT TO FIND MOLD https://inspectapedia.com/sickhouse/Light_Aim_Detects_Particles.php

On 2019-02-12 by Sue baker

I was wandering the outcome of your situation. I have similiar problem but not sure what the culprit is. My entire house glowed with blue fibers.

Cloths were the worst. Figured out my dryer lint thing was clogged. Not sure if things are improving yet. New bed causes itching.

Thought it was the fiberglass fire retardant, but dont see green only blue. Bought light on amazon so it might not be strong enough. Havent seen any spots on walls for mold, but really think that's the culprit . Could you find mold that was not seen without the black light?

On 2018-11-25 00:54:13.153013 by (mod) -

Thank you for the compliment Aaron.

We also welcome questions, critique, and content suggestions.

On 2018-11-25 by Arron -

Thank you ....this is very helpful, I will use it in my research study

On 2018-11-20 by (mod) - check with your doctor, then clean up the contaminants, then fix the cause

Dawn

First you need to be guided by a doctor whom you trust.

Next, no clean room nor machine nor magic bullet nor special covers etc. is a substitute for finding and removing any significant mold reservoirs in the building or home, and fixing whatever has caused mold growth in the first place.

On 2018-11-20 18:19:55.483323 by Dawn

I am suffering from “severe toxic mold poisoning” and I’m having an extremely difficult time not reacting to my “world” now.

I have tried to create a clean room in my home to start my healing process after water damage and professional remediation.

In this room I have a new bed, an oxygen concentrator, 2 air purifiers, new linens and basic pajamas and loungewear.

I have a downstairs bedroom and at this point my bedroom has a hotter temp than any other room in the home.

You can actually feel the heat as soon as you open the door and this is even when the bedroom window open and an outside temp in the high 50’s. We had just put in new carpet prior to discovering the water damage in the attic (2 months) and I have removed any item that hasn’t been cleaned with EC1.

The walls have been washed with EC1 twice and the carpet has been professionally cleaned 3. My new bed (2 months) feels as if there is a hot force field around it. My oxygen concentrator gives off almost no detectable heat. I have been financially ruined trying to survive and heal at the most basic level and this includes “professional testing” that “cleared” my home and air quality .

I am only getting worse and nights in this room are extremely difficult and getting worse no matter how much it’s cleaned. I tried the black light technique last night and my entire room glows yellow/white to some degree. Specs and fibers are on everything. Pls share with me what could possibly be presenting this way.

On 2017-10-24 by Clint Richardson

Inhaled mold unknowingly for a couple years. Since then I have been on antifungals for a very long time. Now the back of my throat glows under UV light. My skin ejects a powdery substance that also glows.

wikiwild@gmail.com

On 2014-08-01 by (mod) - Ordinary water won't show up the same as cat pee

Ordinary water won't show up the same as cat pee - the latter will floresce.

On 2014-08-01 by Ann

I got a wood floor and I think my cat had a wee and it gone black how do I know if it cat wee or damp please help me

On 2014-03-14 by (mod) -

Thanks Kitty, you're correct. You refer to the Woods Test for dermatophytosis or ringworm (which is not a worm but one of several fungi such as Tricbophyton or Microsporum that invade the skin), using a UV light combined with a magnifying lens. This approach is not as reliable as your comment suggests, however, as it will miss about half of the infecting fungal occurrences.

A veternarian may use a Woods Test as a quick scan but he or she would not rely upon that approach and would also use a fungal culture test or microscopic examination of hairs from the suspected site.

While UV light can indeed produce useful environmental findings, in my opinion, I would not agree that it is a comprehensive scan.

There is a danger in using any inspection method that is by its nature not sufficiently broad, as drawing a false conclusion that a risk is absent can in fact put occupants at greater risk than before - thinking that the risk is absent can make people ignore important symptoms.

In sum, absence of evidence is not evidence of absence.

On 2014-03-14 by kitty

You forgot some fungus. Some strains of ringworm glow apple green. Not sure if it glows in the environment though or only on skin.

Would be interesting to know e.g. if my pet is infected with the strain of ringworm that does glow under Wood's lamp, can I use it to detect environmental contamination to simplify disinfection of the environment or not.

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• BLOOD in ART WORKS, TESTING FOR
• LIGHT, GUIDE to FORENSIC USE

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