Advanced Industrial Hygiene
Traditionally, industrial hygienist sampling has primarily used calibrated sampling pumps and a sampling train. Advances in the field have added the option of using passive sampling badges for some chemical hazards. Discuss any personal experience you have using each type sampling method. If you do not have experience with the methods, discuss your opinions about the pros and cons of the methods based on your readings for this unit.
(Note: That means you will read the info in the text and in the Unit guide and form an informed opinion on choices of sampling train or passive sampling. Providing an example would help, check the literature and find a sampling badge to compare with the use of a sampling train, if you like. Reference the source of that info, if might be a manufacturer web page-SKC and 3M are examples of companies who sell passive dosimeters).
If you were performing sampling in a facility you are familiar with, which method(s) would you prefer to use, and why?
Please include the name of the person or question to which you are replying in the subject line. For example, “Tom’s response to Susan’s comment.”
ALSO PLEASE REPLY TO ANOTHER STUDENTS COMMENT BELOW
Frank:
Throughout my career I have been around both types of devices. I have not actually tested or calibrated the pumps we utilized in the volunteer department, but have watched the operator/captain calibrate and use them during drills and training sessions, They also were the ones to operate then bulb pump during any hazmat response. In my most recent job in the oil and gas industry, I worked with crude pipelines where it was a requirement to have constant monitoring via the passive hydrogen sulfide (H2S) monitor attached within our breathing zone. As to which device I would choose to utilize would be determined on what factors are needing to be monitored. With certain occasions the bulb pump and or the train sampling methods would be required, whereas other times passive monitoring would be necessary. The train and/or pump sampling would give me a more immediate test result in real time compared to the passive monitor badges which may have to be sent out to a laboratory for results and acquire an accumulative set of data.
MOS 6301, Advanced Industrial Hygiene 1
Course Learning Outcomes for Unit III
Upon completion of this unit, students should be able to:
4. Assess methods for performing industrial hygiene workplace analysis.
4.1 Summarize information from published sampling/analytical methods.
4.2 Calculate minimum required sampling times based on chosen sampling/analytical methods.
4.3 Describe industrial hygiene sampling processes.
Course/Unit
Learning Outcomes
Learning Activity
4.1
Unit Lesson
Chapter 6, pp. 119133
Chapter 7, pp. 144154
Chapter 11, pp. 248250
Chapter 13, pp. 301309
Presentation: Unit III PowerPoint
Unit III Scholarly Activity
4.2
Unit Lesson
Chapter 6, pp. 119133
Chapter 7, pp. 144154
Chapter 11, pp. 248250
Chapter 13, pp. 301309
Presentation: Unit III PowerPoint
Unit III Scholarly Activity
4.3
Unit Lesson
Chapter 6, pp. 119133
Chapter 7, pp. 144154
Chapter 11, pp. 248250
Chapter 13, pp. 301309
Presentation: Unit III PowerPoint
Unit III Scholarly Activity
Reading Assignment
Chapter 6: Gases and Vapors, pp. 119133
Chapter 7: Aerosols, pp. 144154
Chapter 11: Noise, pp. 248250
Chapter 13: Thermal Stressors, pp. 301309
In order to access the following resources, click the links below.
The presentation contains images of equipment that was discussed in the lesson. Reviewing the presentation
may provide a better understanding of the material in the lesson, especially if you have never performed IH
sampling before. The PowerPoint presentation also contains examples of calculations that you might be
required to perform in the unit assignment.
Click here to review the Unit III PowerPoint Presentation. Click here to download the PDF version of the
presentation.
UNIT III STUDY GUIDE
Evaluating Personal
Exposures in a Workplace
https://online.columbiasouthern.edu/bbcswebdav/xid-112754789_1
https://online.columbiasouthern.edu/bbcswebdav/xid-112754788_1
MOS 6301, Advanced Industrial Hygiene 2
UNIT x STUDY GUIDE
Title
Unit Lesson
After understanding how to anticipate and recognize hazards, the industrial hygienist must decide how to
evaluate the risks associated with the identified hazards. This is the task that most workers associate with the
field of IH. Many workers can remember when an industrial hygienist showed up at the worksite and required
certain employees to wear pumps and other devices for the entire work shift. Even though the sampling is
being performed to decrease employees health risks, this is also the task that many workers will object to
because they view the sampling devices as being intrusive and difficult to wear. In many cases, the most
difficult job the industrial hygienist has is to convince workers of the benefits of wearing a sampling device for
their work shift. In this unit, we will look at the different ways IH sampling can be performed and how to make
sure the data you produce is accurate and precise, in other words useful.
IH Sampling Basics
The essence of IH sampling for chemical hazards is passing a known volume of air through some media to
remove the chemical of interest from the air, thus, collecting it on the media. The media are then sent to a
laboratory where it is removed from the collection media and analyzed to determine the quantity of the
chemical that was collected. The air concentration can then be determined by dividing the quantity of the
chemical that was collected by the volume of air that was pulled through the media (Fuller, 2015). That
sounds simple enough, right? What you must consider is that the results you get from sampling for exposures
in a workplace will rarely be equal to the actual exposures that were present. Why? Because errors can enter
into the process virtually at any step.
Therefore, one of the biggest problems you might face is making sure that errors are minimized as much as
possible. Consider what happens if you are off on your determination of the volume of air collected, the
laboratory is off in determining the quantity of the chemical that was collected, someone makes a mistake on
any calculations, or the worker being sampled muddles the sample during the sampling period. Each of these
errors would be cumulative, so if each step introduced only a 5% error, the overall error of the exposure
concentrations could be greater than 25%. The textbook has a good discussion of errors on pages 120121
(Fuller, 2015). Therefore, how do you minimize the error when you evaluate exposures?
Minimizing Errors in Sampling
The first step is making sure you use validated methods for sampling and the laboratory uses validated
methods for analyzing your samples. There are two organizations that publish validated and semi-validated
sampling and analytical methods, the Occupational Safety and Health Administration (OSHA), and the
National Institute for Occupational Safety and Health (NIOSH).
Understanding how the methods are validated can help you understand how errors can enter into the
evaluation process. OSHA has established a procedure for validating sampling and analytical methods. In
order to be validated, research must consider five variables associated with the actual sampling, four
variables associated with the laboratory analysis of the samples, and four variables associated with the
overall method (Eide, Simmons, & Hendricks, 2010).
The variables associated with the actual sampling are sampler capacity, sampler rate, sampling interferences,
extraction efficiency, and the effects of storage (Eide, Simmons, & Hendricks, 2010). Research is conducted
to determine how much of the chemical can be collected on a sampler before 5% of the chemical breaks
through without being collected. The research then identifies a sampling rate or range of sampling rates for
which the collection is the most efficient. Any other chemicals that could interfere with the collection of the
chemical of interest by lowering the collection efficiency must also be identified. Once the chemical is
collected on the sampler, it has to be extracted in order to be analyzed. The amount that can be extracted is
determined and reported as a percentage. OSHA typically likes to see a collection efficiency greater than 90%
(Eide, Simmons, & Hendricks, 2010). Finally, research must be performed to see how long the sampling
device can be stored at specific temperatures before the chemical that was collected starts to degrade.
MOS 6301, Advanced Industrial Hygiene 3
UNIT x STUDY GUIDE
Title
The variables associated with the analytical procedure are the analytical detection limit, calibration of the
analytical instrument, analytical interferences, and qualitative analysis. Basically, research must determine
what is the lowest quantity of the chemical that can be detected by the analytical method, the standard error
of the analysis (calibration), any chemicals that might interfere with detection of the chemical of interest during
the analytical process, and means that can be used to aid in determining the chemical is present during the
analysis (Eide, Simmons, & Hendricks, 2010).
Overall Sampling Method Accuracy
The variables associated with the overall procedure are the overall detection limit, the reliable quantitation
limit, precision, and reproducibility (Eide, Simmons, & Hendricks, 2010). Basically, this analysis is used to
determine, overall, what is the lowest quantity of the chemical that can be detected and quantified, how
precise the results should be, and how easily the analysis can be reproduced. The detection limit and the
quantitation limit are similar. The difference is that the detection limit is the lowest quantity that can be
detected (i.e., the analysis shows it is there, but may not be able to determine the exact concentration), while
the reliable quantification limit (RQL) is the lowest quantity of the chemical that can be reliably quantified (i.e.,
we can determine the exact concentration). For overall precision, OSHA requires the 95% confidence interval
to be within +25% (Eide, Simmons, & Hendricks, 2010).
You can see that a tremendous amount of effort must be taken to validate a sampling and analytical method
used by an industrial hygienist to evaluate chemical exposures. The result is a method that will hopefully,
determine exposures within + 25% of the actual exposures that are present. Of course, this means the results
will likely not be 100% accurate. This will present difficulties in using the results to compare with occupational
exposure limits (OEL). We will discuss these difficulties in the following unit.
Choosing a Sampling Method
For this lesson we will look at the procedures you would use to decide which method you would use to
evaluate an exposure and then how to use the method in actual practice. For our example, we will look at
NIOSH method 2027 to evaluate exposures to acetone. You can access the method using this document.
Notice that the method is titled Ketones and can be used to sample for seven different ketones including
acetone.
The first decision the industrial hygienist must make is what sampling media to use. For ketones, method
2027 indicates that a solid sorbent tube containing two sections of silica gel (one with 500 mg and one with
1000 mg) is used (Ashley & OConnor, 2017). It is common for a sampling tube to contain two or more
sections of an adsorbent. Acetone would be collected on the first section. When acetone is detected on the
second (backup) section, it indicates that breakthrough has occurred. In other words, because either the
concentration of acetone was too high or the flow rate was too high, not all the acetone was collected, and
some broke through the first section. Having more than 5% breakthrough on the tube can invalidate the
sample results.
The chosen sampling method will include a recommended flow rate or range of flow rates. Method 2027
recommends a flow rate between 0.05 liters per minute (l/min) and 0.1 l/min (Ashley & OConnor, 2017). The
recommended flow rate is based on a range of concentrations that were tested during the validation of the
method. In Table 3 of the method, you can see that the range for acetone was 0.0226 milligrams (mg)
collected on the tube (Ashley & OConnor, 2017). With experience, an IH can choose to use higher or lower
flow rates depending on the expected air concentrations of acetone in the work environment. You might
choose to use 0.05 l/min if you expect relatively high concentrations of acetone to be present and to use 0.1
l/min if you expect a fairly low concentration to be present.
After you choose the flow rate, you must calibrate the sampling train (sample pump connected to the
sampling tube) to ensure you are using the correct flow rate. There are two basic levels of calibration devices
you can use: primary calibration devices and secondary calibration devices. A good discussion of the
differences in the two types of calibration devices is present on page 146 of the textbook (Fuller, 2015). In
some cases, industrial hygienists will calibrate a secondary calibration device like a rotameter against a
primary calibration device and use the rotameter to check flow rates periodically in the field during the
sampling event.
https://www.cdc.gov/niosh/docs/2014-151/pdfs/methods/2027.pdf
MOS 6301, Advanced Industrial Hygiene 4
UNIT x STUDY GUIDE
Title
Collecting an IH Sample
Another important consideration is how long to collect a sample. The method will provide you with some
guidance. For example, method 2027 recommends collecting a minimum of 2 liters of air and a maximum of
10 liters of air (Ashley & OConnor, 2017). You can use that recommendation to calculate a minimum and
maximum time to collect the samples by using the flow rate you chose. For example, if you chose to use a
flow rate of 0.1 l/min and the maximum recommended air volume of 10 L, you would divide the 10 L by 0.1
l/min to get 100 minutes. Understand that the recommended volumes in the method are based on the
research with the concentration shown in Table 3 of the method. If you wanted to evaluate the exposures for
an employee over an entire eight-hour work shift, you could sample for a longer period if you expected
exposure concentrations to be much lower than the concentrations shown in the method. The risk you take in
sampling for a longer period is that you could have a breakthrough greater than 5% resulting in an invalid
sample. Another approach would be to change out the sampling tube periodically, breaking up a work shift
into a series of samples with lower volumes. This approach would result in additional costs for analysis.
It is also important to make sure that you collect an adequate volume of air, so the analytical process can
actually quantify a result that is less than the published OEL that you decide to use. For example, if you had a
permissible exposure limit (PEL) of 0.1 parts per million (ppm) for a chemical, but you did not collect an
adequate volume of air, your reported analytical result could be <0.2 ppm. This result would be inadequate for
your evaluation because the exposure could be above the PEL, but you would not know that. Therefore, it can
be important to be able to calculate the minimum volume of air required to receive results that are less than
the OEL you choose.
This is one of the calculations you will be required to complete for this units assignment. Basically, you use
the limit of quantification for the chemical that is reported in the method and the flow rate you choose from the
method. There is a PowerPoint presentation that you can access in the required readings section that guides
you through the calculations required. The textbook also contains a discussion of the calculation on page 122
(Fuller, 2015).
Personal Versus Area Samples
A final consideration is whether you will collect personal samples or area samples. Personal samples are
placed on the worker with the collection media placed within the workers breathing zone. OSHA (2014) has
defined the breathing zone as being as close to the workers nose and mouth as possible in a hemisphere
forward of the shoulders six inches to nine inches from the nose and mouth. An area sample is simply a
sample that is placed within an area to determine the concentration in the area. For sampling to evaluate the
risks associated with personal exposures, personal samples are the preferred method.
After you complete the sampling, you calibrate the flow rate of the sampling train again to determine if there
was any change in flow rate. There is no set difference that is required, but most industrial hygienists will
invalidate a sample if the difference between the two calibrations is greater than 10%. You must then review
the method one more time to see if there are any special requirements for shipping. Some samples must be
shipped in a cooler with an ice pack to maintain a low temperature. Other samples must be placed in a
stabilizing solution prior to shipping. The chosen method will tell you if anything is required. Method 2027
shows that there are no special requirements for shipping the acetone samples (Ashley & OConnor, 2017).
There are other types of sampling that do not use sampling media and sampling pumps. For example, noise
exposures are evaluated using either a sound level meter (SLM) or, more commonly, a noise dosimeter. The
SLM and dosimeter also have to be calibrated prior to use. Manufacturers have a calibration method for their
devices. Pages 248 and 249 of the textbook contain information about evaluating noise exposures (Fuller,
2015).
MOS 6301, Advanced Industrial Hygiene 5
UNIT x STUDY GUIDE
Title
References
Ashley, K., & OConnor, P. F. (Eds.). (2017). NIOSH manual of analytical methods (NMAM) (5th ed.).
Retrieved from https://www.cdc.gov/niosh/nmam/default.html
Eide, M., Simmons, M., & Hendricks, W. (2010). Validation guidelines for air sampling methods utilizing
chromatographic analysis (Publication Index No. T-005). Retrieved from
https://www.osha.gov/dts/sltc/methods/chromguide/chromguide.pdf
Fuller, T. P. (2015). Essentials of industrial hygiene. Itasca, IL: National Safety Council.
Occupational Safety and Health Administration. (2014). OSHA technical manual: Section II, Chapter 1,
Personal sampling for air contaminants. Retrieved from
https://www.osha.gov/dts/osta/otm/otm_ii/otm_ii_1.html
Suggested Reading
You are encouraged to look at some of the methods in each publication as you will using these during some
of the assignments for the course.
The OSHA methods can be accessed at the Alphabetic Index of Sampling and Analytical Methods web page.
The NIOSH methods are published as the NIOSH Manual of Analytical Methods (NMAM) 5th Edition.
In order to access the following resources, click the links below.
The CSU Online Library contains many articles that relate to the Unit III readings. The following are just a few
of the related articles that can be found in the Academic Search Complete database.
Industrial hygienists can use two basic methods to evaluate personal exposures to chemicals, active or
passive sampling. Active sampling uses a sampling pump with some type of collection media. Passive
sampling uses a sampling badge with no sampling pump. The following article evaluates the results from
sampling using both methods for formaldehyde.
Lee, E. G., Magrm, R., Kusti, M., Kashon, M. L., Guffey, S., Costas, M. M., Harper, M. (2017). Comparison
between active (pumped) and passive (diffusive) sampling methods for formaldehyde in pathology
and histology laboratories. Journal of Occupational and Environmental Hygiene, 14(1), 3139.
Retrieved from
https://libraryresources.columbiasouthern.edu/login?url=http://search.ebscohost.com/login.aspx?direc
t=true&db=a9h&AN=120263473&site=ehost-live&scope=site
Advances in consumer electronics have produced numerous apps that can be used by anyone with a smart
phone. One app allows you to monitor noise levels as if your phone were a sound level meter. The question
is, how accurate are the readings? The following article reports the results of a comparison of readings using
a calibrated sound level meter and three different apps.
Ibekwe, T. S., Folorunsho, D. O., Dahilo, E. A., Gbujie, I. O., Nwegbu, M. M., & Nwaorgu, O. G. (2016).
Evaluation of mobile smartphones app as a screening tool for environmental noise monitoring.
Journal of Occupational and Environmental Hygiene, 13(2), D31D36. Retrieved from
https://libraryresources.columbiasouthern.edu/login?url=http://search.ebscohost.com/login.aspx?direc
t=true&db=a9h&AN=112262955&site=ehost-live&scope=site
https://www.osha.gov/dts/sltc/methods/toc.html
https://www.cdc.gov/niosh/nmam/default.html
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MOS 6301, Advanced Industrial Hygiene 6
UNIT x STUDY GUIDE
Title
New sampling methods are periodically developed. We discussed some of the validation variables that must
be determined. The following article summarizes the methods used to determine the optimal flow rate for a
new device used for performing size-selective samples. These types of samples are used when the chemical
hazard of concern is only the respirable fraction of particulates that are present.
Lee, T., Thorpe, A., Cauda, E., Tipton, L., Sanderson, W. T., & Echt, A. (2018). Laboratory comparison of new
high flow rate respirable size-selective sampler. Journal of Occupational and Environmental Hygiene,
15(10), 755765. Retrieved from
https://libraryresources.columbiasouthern.edu/login?url=http://search.ebscohost.com/login.aspx?direc
t=true&db=a9h&AN=133105290&site=ehost-live&scope=site
An alternate approach to evaluating exposures in the workplace is to use real-time, direct-reading
instruments. These types of instruments are limited in their ability to take time-weighted average samples in
the workers breathing zone. The following article evaluates a new portable instrument that is said to be more
suitable for collecting samples from a workers breathing zone.
Soo, J.-C., Lee, E. G., LeBouf, R. F, Kashon, M. L., Chisholm, W., & Harper, M. (2018). Evaluation of a
portable gas chromatograph with photoionization detector under variations of VOC concentration,
temperature, and relative humidity. Journal of Occupational and Environmental Hygiene, 15(4), 351
360. Retrieved from
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t=true&db=a9h&AN=128834249&site=ehost-live&scope=site
Learning Activities (Nongraded)
Nongraded Learning Activities are provided to aid students in their course of study. You do not have to submit
them. If you have questions, contact your instructor for further guidance and information.
The National Institute for Occupational Safety and Health (NIOSH) publishes validated sampling and
analytical methods for chemical hazards that are used by most industrial hygienists. Access the document
NIOSH Manual of Analytical Methods (NMAM) at https://www.cdc.gov/niosh/nmam/default.html. Look for
analytical methods for some chemicals you are familiar with. Are there some chemicals you use that do not
have a validated method in NMAM?
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https://www.cdc.gov/niosh/nmam/default.html
