How Do You Measure Odor?

This may seem like a silly question, since everyone has a nose, but we’re scientists here on the NonScents team. We want to know what aroma-causing compounds we’re working on, exactly how effective our products are, and how long they take to work.

Here are the methods we use to make sure that when you buy a NonScents product, you’re getting truly amazing, scientifically proven odor control.

Odor Testing Methods

Gas Chromatography–Mass Spectrometry (GC-MS)

This method is the most exacting & informative way to judge odor. Rather than subjectively judging smell intensity, GC-MS allows you to see the precise odor causing compounds present in an odor-generating substance (like organic thiol compounds) and what their concentrations are.  When you then add odor control products to the odor-creator, you can test how those compounds have changed in concentration.

When we say our technology is far more effective than baking soda, enzyme, or charcoal based products, it’s because we’ve done side by side scientific testing with GC-MS (along with other methods) to see how these various products break down odor compounds.

GC-MS not only takes specialized equipment, it also requires a lot of expertise & training to perform at this level – so we work with the University of Washington for our GC-MS testing (which has the added benefit of being an independent, unbiased institution).

Ammonia & Hydrogen Sulfide Meters

Two of the compounds that produce a lot of world’s bad odors from organic sources are ammonia and hydrogen sulfide. Both compounds can be measured with handheld meters that output a simple numerical value. This is the way we do a lot of our quantitative testing here at the OxiScience lab – they give us data points that are easy to chart for long term analysis.

Color Indicator

When we take photos for you to see on the internet or in pamphlets, or when we’re doing a demonstration at a trade show, we need something that’s easy for a non-scientist to understand at a glance. For that we use a color indicator that bonds with organic thiol compounds and then turns yellow. Destroy the odor compounds and indicator doesn’t have anything to react with and the yellow color goes away, making it easy to see (even if it’s a photo and you can’t smell) what’s happened.

Panel of Noses

Yes, of course we have noses, and we use them! We’ve determined that two of our lab staff members have particularly sensitive senses of smell, so we often turn to them for quick gut-check responses. Of course, we can’t rely on that for full scientific results. When we want to actually submit our products to a smell test, we follow a couple of rules:

  • The panel must contain at least 10 participants (ideally 20).
  • All samples must be blind tested (participants don’t know what sample they’re smelling).
  • No more than three samples can be submitted to a panel session – this helps avoid nose fatigue and participants conflating their experiences between samples.
  • If the results don’t surpass the standard deviation on their chart, the panel’s results are inconclusive.

Tested Substances


Ammonia is an odorous substance found in a great many things including (perhaps most notably for our purposes) in urine. It’s part of what gives pet spots that distinctive “pee smell.”

Hydrogen Sulfide (H2S)

Hydrogen sulfide shows up in a lot of things that smell bad – you’d know it best as the aroma of rotten eggs, often used as a “warning smell” in natural gas (which is otherwise odorless).

Organic Thiol Compounds

When we do lab tests we often use thiol as the target. We use two specific varieties – one that’s commonly found in urine, and one that’s a component of “armpit smell”.

We use thiols because they’re an easily purchasable substance that has strong, measurable, consistent malodor properties due to the presence of organosulfurs. These same compounds are also found in other smelly things (particularly skunk spray, but also human sweat, cat pee, and a wide variety of other substances).

When our technology destroys the thiol groups in the tested compounds, we know it will do the same thing wherever it encounters it, regardless of the source, because those specific thiol groups are chemically identical.

Real Cat Urine

As mentioned above with the thiol, the identical compounds that produce these odors are found elsewhere (in consort with different other ingredients), but it’s great to have the exact thing we’re trying to combat handy when testing our cat litter deodorizer and pet odor removal spray.

Previously we were working with goat pee and horse pee (Jeff owns a farm). But we’ve just started working with real cat pee (a joy for our scientists & lab technicians, you can be sure) in the OxiScience lab thanks to donated clumped litter from cat rescue groups in the area. We dissolve portions of the litter, and then spin the liquid in a centrifuge to extract the pee for testing.