Welcome to the St. Croix Sensory Library


You can browse our library by selecting a subject below.


Please feel free to contact our offices directly with questions. We're happy to help.


1 (800) 879-9231  or  651-439-0177

About Odor Testing



Odor Parameters


View this PDF file to learn more about odor parameters such as odor thresholds, odor intensity, odor persistence, hedonic tone, and odor characterization.


Odor Chemistry

Information about Odor Chemistry Coming Soon.

Regulations – About Odor Nuisance







Coming Soon








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North Dakota


West Virginia



Village of Hillside, Illinois

San Luis Obispo, California

Des Moines, Iowa

Denton, Texas

Denver, Colorado

South St. Paul, Minnesota

Shreveport, Louisiana

Sioux City, Iowa

Coming Soon.


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Sensory Standards





ASTM International Standards





International Sensory Standards





ISO Standards

St. Croix Sensory is accredited to
ISO/IEC 17025:2005, General Requirements for the competency of testing and calibration laboratories.



Sensory Books


Environmental Odors



Coming Soon!


Helpful documents about odor sampling.

EPA Methods

Industry Publications

Coming Soon!



Coming soon.

Coming Soon.


Documents to assist in Dispaersion Modeling

Nasal Ranger Field Olfactometry






Nasal Ranger


Case Studies


Nasal Ranger Case Studies Coming Soon.






Top Videos


Check out these top videos highlighting our Nasal Ranger Field Olfactometer.

Products & Materials Sensory Testing

Published Papers

Case Studies

Published Papers

McGinley, M.A., and McGinley, C.M.

AATCC International Conference

American Association of Textile Chemists and Colorists

McGinley, M.A., and McGinley, C.M.

University Kassel - 8th Workshop on Odour and Emissions of Plastic Materials

Kassel, Germany: 27-28 March 2006

Case Studies


Case Studies of Product & Material Testing will be provided soon.



Environmental Odor

Product & Material Testing

Food & Beverage

Odor Sampling

Nasal Ranger


Q: What is ASTM E679?

ASTM E679 is an ASTM International standard method for determination of odor thresholds by a triangular forced-choice testing method.  This standard was first published in 1979 as E679-79, when it replaced the static threshold "Syringe Method", ASTM D1391. In 1991, minor revisions were made and the standard was renumbered E679-91.  In 2004, additional examples were added to the standard and the newest revision is published as E679-04.  This standard was reapproved in 2011.

Q: What is EN13725?

EN13725 is a Committee European Normalisation (CEN) standard method for "Determination of odour threshold by dynamic olfactometry."  EN13725 exceeds the requirements of ASTM E679 with additional QA/QC and assessor selection requirements.


Q: What type of olfactometer does St. Croix Sensory use?

At St. Croix Sensory, we utilize the AC'SCENT Olfactometer.  We developed this olfactometer in the 1990's to meet the newest requirements of ASTM E679 and EN13725.  We run this olfactometer operating in Triangular Forced-Choice mode with a 20-LPM presentation rate.  The AC'SCENT can also be operated in Binary Forced-Choice, Yes/No, or Direct Presentation testing modes.  The AC'SCENT can also be operated at flow rates of 3-LPM to 20-LPM.


Q: What are odor units?

Odor units are a pseudo-dimension applied to odor threshold testing results from testing with an olfactometer.  The olfactometer threshold result is a dimensionless dilution ratio.  Frequently, the units of "odors units" (O.U.) or "odor units per cubic meter" (O.U./m3) are applied to the result.

This dimensionless value refers to the average dilution ratio at the threshold or the number of dilutions needed to bring the odor to this threshold.

Q: What is Odor Intensity?

Odor intensity is determined following ASTM International E544, "Standard Practice for Referencing Suprathreshold Odor Intensity."  It is a measure of the perceived strength of the odor.

Q: How long does it take to receive my results?

For environmental odor evaluations, St. Croix Sensory provides a detailed electronic report within 5-business days after evaluation.  In most cases, reports are received 2-3 days after evaluation.  Fast guarantee report turn-around can be provided at an additional charge.

FAQ's Coming Soon




Q: Where do I get odor sampling equipment?

St. Croix Sensory is a manufacturer and supplier of odor sampling equipment.  Equipment is available for both rental and purchase.  Please contact us for specific information about the equipment you may need.

Q: How do I ship samples to St. Croix Sensory?

All odor samples should be analyzed within an industry standard of 30-hours.  This requires samples to be shipped to St. Croix Sensory via priority overnight shipping (e.g. UPS or FedEx).  In some cases, early AM delivery may be necessary from some locations and depending on the time samples were collected.

St. Croix Sensory provides shipping boxes at no charge (charge for shipping).  These boxes can be sent directly to your sampling site for your convenience. Please contact us for specific information about shipping.

Vacuum Chambers

Q: Does the VAC'SCENT Vacuum Chamber comply with EPA sampling methods?

Yes, EPA Method 18 - Measurement of Gaseous Organic Compound Emissions by Gas Chromatography and Method 0040 - Sampling of Principal Organic Hazardous Constituents from Combustion Sources Using Tedlar Bags.

Q: When I sample, how do I minimize contamination between samples?

Change or purge the Teflon sampling tubing after each sample collection.


Q: Do I need a pump with the VAC'SCENT?

No, the VAC'SCENT has a pump inside. However, if you need to collect a sample over a long period of time (10-minutes to 60-minutes) we recommend you use a variable speed personal sampling pump externally to create the vacuum inside the VAC'SCENT.


Q: What sample tubing should I use?

Teflon tubing should be used for collecting odor samples. St. Croix Sensory can provide you 1/4" Teflon tubing.

Q: What are the ports on the chamber?

There are four ports on the front of the chamber.  Ports A & B (front left) are the integral pump outlet and inlet.  Port C is a valved port for depressurizing the case. Port D is the sample inlet port.  Connecting Port B to Port C will evacuate the air in the case.  The sample will then flow into Port D, and then the sample bag, to balance the pressure.


Q: What size sample bags will fit in the VAC'SCENT?

The VAC'SCENT can be used to fill two 10-L sample bags at one time.  This allows for collection of true duplicates.  A 25-L bag can be used if the dimensions of the bag are appropriate.  Please contact us if you have specific needs. The VAC'SCENT can be built with cases of varying sizes.

Flux Chamber

Q: Does the AC'SCENT Flux Hood comply with EPA sampling methods?

Yes, see EPA document PB86-223161, "Measurement of Gaseous Emission Rates from Land Surfaces Using an Emission Isolation Flux Chamber."


Q: When I use the Flux Hood what flux gas/air do I use?

The protocol for your project may dictate zero-air or high-purity nitrogen (HPN) with or without a helium (He) component.


Q: What is a typical sweep gas (air) rate?

25-liters per minute per square meter is a typical sweep gas rate, which is 3.5-LPM for the 0.13-m2 under the AC'SCENT Flux Hood.


Q: What is the typical sample collection rate?

The Sample collection rate depends on your project protocol; a typical sample collection rate is 1 to 2 LPM.


Q: Where can I buy a Nasal Ranger?

The Nasal Ranger may be purchased by contacting St. Croix Sensory  directly, or contact an authorized Nasal Ranger representative found at the link below.


Q: What does the Nasal Ranger measure?

The Nasal Ranger Field Olfactometer quantifies the perceived odor level as dilutions-to-threshold (D/T).  This is determined as the number of dilution needed to make the ambient air odor just detectable.


Q: Who can use the Nasal Ranger?

Almost anyone can use the Nasal Ranger!  Commonly, air quality control managers, municipality managers and regulators, facility operators, and citizen groups are using the Nasal Ranger to quantify ambient odors.


Q: How often do I need to change the odor filter cartridge?

Both threshold results are based on the dilution-to-threshold principle and are thus a similar measure.  Laboratory olfactometry, following ASTM E679 and EN13725, is best utilized when source odors are being measured (e.g. source stack emission).  Air dispersion modeling is then utilized to predict the impact of those source odors on the community.  Field Olfactometry is performed to quantify the odors in the community; therefore, it is a direct measure of the community impact at that specific moment in time.


Q: How frequently should my Nasal Ranger be calibrated?

St. Croix Sensory is ISO/IEC 17025:2005 Accredited

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