Smell test last step (C) Daniel FriedmanSmell Patch Test - How to Track Down a Building Odor to a Specific Material or Source

  • SMELL PATCH TEST to FIND ODOR SOURCE - CONTENTS: How to find the source of an odor or smell in a building. Simple, photo-illustrated step by step procedure assists in tracking down building odors or smells to a specific surface or material. Using ozone in buildings to "purify air" or to "kill mold" can produce persistent "chemical" odors whose source needs to be identified and removed. Building smell or odor source identification using a smell patch test
  • POST a QUESTION or READ FAQs about using simple methods to track down the source of a building odor or smell
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Smell patch test procedure tracks down odor sources:

How to use paper towels, aluminum foil, and tape to perform a simple but effective odor source test of building surfaces and materials.

This article describes a simple procedure using paper towels and aluminum foil wrap to track down odors in buildings, such as but not limited to tracking down mold smells, sewer smells, plastic smells, chemical odors, animal odors, and even new smells that occur after excessive indoor use of ozone in buildings to try to "kill" mold or remove other indoor odors (skunks or smoke).

Our page top photo shows the last step in the smell-source test procedure, though we recommend that this step be conducted outdoors in fresh air.

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How can I Track an Indoor Odor to its Source?

Smell test setup (C) Daniel FriedmanThe procedure we describe here is easy, inexpensive, and fast - you'll need a day or so, plus some common household materials to track down an indoor smell to the surface or material that is its most likely source.

Depending on what caused the material to smell in the first place, disposal may be the only option. In other cases, amateur or professional cleaning or use of sealant paints may be effective. If you've already tried using an ozone generator to kill an indoor odor, you may have used the equipment improperly.

Ozone or O3 is a highly reactive oxygen molecule that can cause oxidation of materials that it touches. This oxidation, especially of some rubbers and plastics, can leave a horrible smell in the treated building.

Before getting into the details of how to perform the smell patch test, note that there are at least the following odor investigation approaches:

Odor Diagnosis Strategies:

You can start tracking down the cause or source of an odor in one or more of several ways:

  1. ODOR DIAGNOSIS SIX STEPS - taking an orderly approach to odor source tracking
  2. ODOR DIAGNOSIS CHECKLIST - an easy checklist of stuff to examine or test
  3. ODORS GASES SMELLS, DIAGNOSIS & CURE - includes a catalog of places to look when tracking down an odor source
  4. SMELL PATCH TEST to FIND ODOR SOURCE - procedure for testing specific surfaces or items to see if an odor souirce of if they have absorbed and are re-emitting an odor - this article

Using Ozone to Get Rid of Skunk or Mold Smells?

This quote from a reader's email pretty well sums up what happens if you overdo it when using an ozone generator indoors to try to "kill off" odors:

It's a long story, but I used a high powered ozone generator in our house, to get rid of skunk smell. Now I can't get rid of the left over nitric oxide, or whatever odor or gases, that linger in our house. I have been leaving the windows open every day, with running the heat on high (85 degrees) at night, to try to force off-gas the odors/gases.

We have investigated a number of cases of misapplication of ozone generating machines both to "kill mold" (no good, you're leaving toxic or allergenic particles, and you haven't corrected the reason for mold growth in the first place). We have also investigated several cases of excessive ozone-use to try to remove odors from buildings, including fire or fireplace smells, mold smells, pet or animal smells, skunk odors, smoking odors, etc.

Using an Ozone Generator Has Left a Smell in our Home - How do I Get Rid of It?

If you have aired out the building and days or more have passed and you still smell a "new" chemical or plastic or other odor that was not there before you tried using your ozone generator, you'll need to determine just what materials were oxidized by the high levels of ozone in the building.

It's been our experience that once you identify and dispose of the new-smelly material you'll probably be fine. Here are some examples of material we've found giving off horrible smells after misuse of an ozone generator. (Misuse means using the ozone generator to try to kill mold, or running an ozone generator too long at too high a setting in too small a space - overdoing it).

Try the Smell Capture Patch Test to Pin Down a Specific Indoor Odor Source

Smell test setup on carpeting (C) Daniel Friedman

Our friend Jeff May suggested this procedure for pinning down a specific odor test in buildings - it has worked remarkably well for us where ozone had caused an indoor smell that could not be tracked down.

Our photo (left) shows the supplies you need as well as a test set up on the surface of wall to wall carpeting. We have added to, elaborated, and provided details of just how this smell patch test works - below.

Smell test setup (C) Daniel Friedman Smell test setup (C) Daniel Friedman

Odor test patch on wall surface (C) Daniel Friedman

Test patch being removed (C) Daniel Friedman Test patch being removed (C) Daniel Friedman Smell test container opened for sniffing (C) Daniel Friedman Smell test last step (C) Daniel Friedman

Test your control smell patches as follows:

If a smell test is definitive, the test person will usually report very accurately which patches are from a given smell or surface area.

We have had very good results with this procedure when used to narrow down odor sources in an ozone-treated building, and we had up to 95% repeatability when we used additional smell test patches.

What Does the Odor & Smell Patch Test Kit Do or Not Do for You?

This is not a scientific test to capable of identifying the actual chemical constituents of an odor, rather it's a means of odor source location - costing almost nothing compared with paying for an air sample collection and spectrographic analysis.

Once we know the source of a smell or odor, it may be that the simplest, most-economical approach is to remove the off-gassing material or product itself.

There are indeed more technical air test methods used by industrial hygienists who collect one or more air samples in a vacuum container and send that to a lab for characterization, or who may use specific instruments designed to detect the level of specific gases or classes of gases. We will give some examples of these just below.

There are widely-marketed "air tests" sold by a number of companies testing for specific classes of gases such as "VOCs", formaldehyde, or "tobacco" - in my OPINION not something that should be a first step as the number of possible pollutants and even pollutant classes is so great, and as there is no simple single "test" that covers the spectrum.

One should note this concern about "air testing" for odors: even if we knew what chemical soup was in the air that may not be sufficiently diagnostic and it certainly won't be prescriptive - giving a course of action. To take action we need to know:

Resources for Odor & Gas Detection


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