UNIVERSITY OF CENTRAL MISSOURI
SAFE 4140 SAFETY AND HEALTH LABORATORY
LABORATORY EXERCISE REPORT
Page 1 of 2
Laboratory Exercise Number:
Laboratory Exercise Title:
1. Abstract/Executive Summary
• Summary of operations/processes.
• Summary of results relative to applicable Occupational Safety and Health Administration
permissible exposure limits (OSHA-PELs), American Conference of Governmental
Industrial Hygienists threshold limit values (ACGIH-TLVs), and other applicable
occupational exposure limits (e.g., National Institute for Occupational Safety and Health
recommended exposure limits [NIOSH-RELs]; Mine Safety and Health Administration
threshold limit values [MSHA-TLVs]).
Where, when, and by whom was sampling conducted?
What was sampled and analyzed?
Which personnel and areas were sampled?
Materials and Methods
Instruments and media used for calibration, sampling, and analysis.
Calibrated flow rates for both pre- and post-sampling.
Cited methods (e.g., NIOSH, OSHA, other).
Identification of laboratory.
• Tables, figures summarizing calibration, sampling, and analytical data.
• Succinct, factual statements based on observations and measurements.
5. Discussion and Conclusions
• Significance of findings.
• Control measures (e.g., work practices, ventilation, personal protection equipment [PPE]
• Follow-up sampling and analysis.
• Record keeping.
• References (textbook, cited methods) in APA format.
• Field monitoring forms.
• Other applicable information (as needed).
Page 2 of 2
Evaluation of Airborne Total Particulate: Integrated
Personal and Area Monitoring Using an Air Sampling
Pump with a Polyvinyl Chloride Filter Medium
At the completion of Unit 2 including sufficient reading and studying of this and related
reference material, learners will be able to correctly:
Name, identify, and assemble the components of a common sampling train, including the specific
sampling medium, used for conducting integrated sampling of airborne total nuisance dust or
particulate not otherwise classified, hereafter referred to as total particulate.
• Name, identify, and assemble the applicable calibration train that uses a primary standard for
measuring flow rate of a multi- or high-flow air sampling pump.
• Calibrate a multi- or high-flow air sampling pump with the applicable representative sampling
medium in-line, using a mechanical or electronic frictionless bubble-tube.
• Summarize the principles of sample collection of airborne total particulate.
• Conduct integrated sampling of airborne total particulate.
• Prepare samples for analysis of collected particulate using gravimetry.
• Name and identify the components of a mechanical or electrical balance.
• Name, identify, and assemble the components necessary for analysis of samples for total
particulates using an electrobalance.
• Check the calibration of an electrobalance using standard weights.
• Summarize the principles of sample analysis of filters used for collection of airborne total
• Conduct analysis of a sample for total particulate using an electrobalance.
• Perform applicable calculations and conversions related to pre- and post-sampling flow rate of an
air sampling pump, average flow rate of an air sampling pump, pre- and post-weight of a filter
medium, sampling time, sampled air volume, weight of total particulate collected, and concentra
tion of total particulate in units of milligrams per cubic meter (mg/m3).
• Record all applicable calibration, sampling, and analytical data using calibration, field sampling,
and laboratory analysis data forms.
Occupational exposure limits, such as American Conference of Governmental Industrial Hygien
ists threshold limit values (ACGIH-TLVs) and Occupational Safety and Health Administration
permissible exposure limits (OSHA-PELs), for airborne particulates have been established for many
individual elements and compounds based on their inherent toxicities. There are situations when it
is important to know what the concentration of par ticulate, both hi ghly toxic and practically nontoxic,
is in a given area. It is equally important to determine what an individual’s external exposure is to
total particulate rather than a specific type. Situations also exist in which there are no occupational
exposure limits for a specific type or mixture of particulate air contaminants. These materials may
be generically classified and sampled and analyzed as total dust or particulate. In either situation,
measurements of total particulate, that is, particulate mixtures of various sizes and compositions,
are f requently warranted. There is an OSHA-PEL for total dust and an ACGIH-TLV for particulates
not otherwise specified. Sampling and analytical methods are available for these particulates, and
involve moving an airstream into and through a filter collection medium. Airborne particulates are
electrostatically attracted to, intercepted by, and impacted on the filter medium, resulting in separation
of the particulates from the air without regard to particle size or composition (Figure 4.1).
The ACGIH also has TLVs based on size-selective sampling of three categories of particulate
mass fractions'. These three categories of TLVs are for materials deemed hazardous when they
Anywhere in the respiratory tract (inhalable particulate mass-TLV)
Anywhere within the lung airways and the gas-exchange region (thoracic particulate mass-TLV)
Anywhere in the gas-exchange region (respirable particulate mass-TLV)
Size-selective instrumentation and methods are needed and have been established to sample,
analyze, and characterize airborne particulate relative to these categories. Some size-selective
samplers are summarized in Unit 5.
FILTER MEDIUM FOR TOTAL PARTICULATE
The sample medium is a 37-mm diameter polyvinyl chloride (PVC) filter with a 5.0-(im pore
size. The diameter (37 mm) of the filter provides cross-sectional surface area for deposition and
collection of particulate. The pore size (5 (im) causes particulates with diameters greater than the
pore diameter to collect on the surface of the filter. Particulates with diameters less than the pore
size are also collected. These particles are collected within the pores due to an electrostatic attraction
between the particles and the filter. The fine particulate is collected primarily via diffusion into the
filter material whereas the relatively coarser particulate is intercepted and impacted within the
medium. Collection efficiency increases as particulates accumulate on the filter. The larger pore
size (5(im) filter is used relative to smaller pore sizes (0.45 to 0.8 (im) to reduce clogging and
overloading of the filter since total particulate is composed of diverse particle sizes.
Since sample preparation and analysis involves a weighing or gravimetric procedure, filters are
stored in a dcssicator until use. Standard dessicators contain a hygroscopic medium such as silica
gel crystals. The purpose of dessication is to absorb any water that is present on the filter that
would result in an erroneously higher weight when the filter is weighed pre- and post-sampling.
PVC plastic filters are used instead of a paper cellulose type since the plastic is relatively hydrophobic. Nonetheless, dessication helps assure that the pre-weight is due only to the filter, and post
weight is due only to a combination of the filter and collected particulate. Filters should be dessicated
for approximately 24 h prior to weighing. Dessication can be accelerated and incubation time
reduced to less than 30 min if a vacuum dessicator is used.
The filter medium is positioned on a cellulose support pad and secured within a 37-mm threestage plastic cassette (Figure 4.2). The bottom or outlet stage holds the porous support pad and the
filter. It has an orifice (hole) in the center that serves as the outlet port for sampled air to exit the
cassette. The middle stage is a ring-shaped spacer or cowl that increases the depth or height of the
cassette to facilitate more even deposition of the particulates from the air as it enters the cassette.
The top or inlet stage contains a hole in the center that serves as the inlet port for sampled air to
enter the cassette.
Filters can be overloaded with particulate if airborne concentrations and sample volumes are
too high. Particulates can visibly accumulate and form a mound or inverted cone in the center of
the filter directly below the inlet orifice of the cassette. The accumulated particulate can break off
and be lost during sample analysis if the cassette and sample are not handled carefully. Filters
can also become contaminated with particulate if a dusty cassette is not wiped off prior to
disassembling for analysis. In either case, loss of particulate from the filter or contamination of
the filter can result in erroneous data and an invalid sample. These precautions are applicable for
samples collected for any airborne particulate, including total dust, respirable dust, fibers, and
metal dust and fume.
The sample collection medium is prepared by pre-weighing a filter for each field sample and
blank that is going to be collected and ultimately submitted for laboratory analysis. Immediately
prior to pre-weighing, the dessicated filter is passed across an ionization device to eliminate any
static charge that may be present on the filter, and cause contamination due to an unwanted attraction
of airborne particulate. The anti-static device contains a radioisotope such as poionium-210. A filter
is pre-weighed using an electrobalance to determine pre-weight. The pre-weighed filter is subse
quently positioned on a cellulose support pad in a three-stage plastic cassette. The cassette is
assembled, and plugs are inserted at the inlet and outlet ports or orifices. When used for sampling,
the orifice plugs are removed and the cassette is attached to an air sampling pump using a length
of '/4 in. internal diameter (i.d.) flexible hose (Figure 4.3). Typical sampling rates range from 1.5
to 2.0 1/min. Following sampling, the cassette is removed and plugs are reinserted in the open
orifices in the field. The sample is then transported to a laboratory for analysis.
A brief outlined summary of sample collection follows.
The air sampling pump is calibrated pre- and post-sampling to adjust or determine flow rate using
a manual or electronic calibrator with representative media (i.e., an assembled three-stage cassette
containing a 37-mm, 5.0-gm pore size PVC filter and support pad) in-line (Figure 4.4).
Pre- (Qpre) and post-sampling (Q^) flow rates are determined by measuring the average time (Tavg
sec) based on three trials (Z T, 2 3/3) for a bubble to traverse a specific volume (V cc) of the bubbletube.
Figure 4.4 Calibration train for total particulate composed of (a) high-flow pump connected with flexible hose
to (b) a 37-mm PVC filter in three-stage cassette in-line with (c) a frictionless bubble-tube.
• Average flow rate (Qavg) is based on the average of pre- (Qpre) and post-sampling flow rates.
• Typical flow rates for sampling total particulate are 1.5 to 2 I/min.
(ii) Preparation for Sampling
A weighed PVC filter plus unweighed support pad are inserted into a plastic cassette which is
then assembled and labeled.
The sampling train is assembled and consists of a multi- or high-flow pump; 74 in. i.d. flexible
hose with clips; and a 37-mm three-stage plastic cassette containing a weighed 37-mm, 5.0-gm
pore size filter on an unweighed cellulose support pad.
(iii) Conducting Sampling
A labeled plastic cassette is positioned with the inlet port facing downward and attached within
the breathing zone. An air sampling pump connected to the cassette is clipped to the belt of the
worker for personal sampling. The sampling train is positioned and secured in a specific location
for area sampling.
The pump is turned “ON” and start time is recorded.
After a specified time, the pump is turned “OFF’ and stop time is recorded.
The orifice plugs arc inserted into the inlet and outlet ports of the plastic cassette and the sample
is transported to laboratory for analysis.
The sampling method for total particulate is similar to those methods used to detect and measure
specific particulate air contaminants. The most significant difference is the method of analysis.
Whereas specific particulate air contaminants require an analytical method that will both identify
the specific analyte and measure the amount collected, analysis of total particulate only involves
measurement of the amount (weight) collected via a simple gravimetric procedure. Accordingly,
the identification of the specific components or composition of the collected particulate matter is
not determined. Analysis of the sample involves a gravimetric method using a mechanical or
electrical balance (Figure 4.5). The gravimetric procedure involves comparison of post- and pre
weight of filter. Theoretically, the pre-weight is the weight of only the filter and the post-weight is
the weight of only the filter plus the collected particulate. The difference in weights (post-sample
minus pre-sample filter weight) represents the total particulate collected. Gravimetric analysis is
the most simplistic of the major analytical methods. A brief outlined summary of the components
and the principles follows.
Sample/weighing chamber: transparent glass enclosure with sliding door/sash where filter is
placed and shielded from moving airstreams and related turbulence during weighing
Weighing pan: stage on which filter is placed for weighing
Mechanical or electrical balance mechanism: mechanical or electrical device that responds to
weight of filter
Readout: responds to mechanical or electrical signal from balance mechanism and provides
weight of filter
(ii) Principle of Analysis
Following sampling and prior to analysis, the orifice plugs are removed from the cassette that
is placed in a dessicator to allow time for absorption of water that may have sorbed to the
particulate and filter during sampling.
Following dessication, the cassette is disassembled and the filter is removed and weighed to
determine the post-weight to the nearest 0.001 mg.
To minimize the attraction and contamination of the filter and sample, they are passed through
an ionization device to eliminate static charge during pre- and post-sampling weighing.
(iii) Determination of Concentration of Total Dust
Determine the amount of total particulate collected by subtracting filter pre-weight from filter
post-weight and express amount as weight in milligrams (mg).
Total Particulate (mg) = Filter Post-weight (mg) +! Filter Pre-weight (mg) (4.3)
Determine the sampled volume of air by multiplying sampling time (T [min]) by average
sampling flow rate (Q [1/min]) and convert liters (I) to cubic meters (m3).
Air Volume (m3) = T (min) x Qavg (1 / min) X +!
• Determine the concentration of total particulate by dividing the weight (mg) by sampled volume
of air (m3) and express concentration in units of milligrams of total particulate per cubic meter
of air (mg/m3).
Total Particulate (mg/m3) = Zgtal_Particulate_(mg)
Air Volume (m )
• Note: The adjusted concentration (C) can be calculated by subtracting the weight of particulate
measured on a blank PVC filter (B) from the sample PVC filter (S); dividing by air volume
sampled (V); and correcting for sampling efficiency (E), which is equal to < 1 depending if / . . # !
or less efficiency is attained.
UNIT 4 EXERCISE
The exercise will provide the fundamental concepts for conducting integrated sampling for total
particulate using a filter medium. In addition, a common and related analytical method using an
electrobalance is introduced. Thus, the exercise will focus on sampling and analysis of total
particulate. The material and methods are based on a modification of National Institute for Occu
pational Safety and Health (NIOSH) Method 0500. Place a check mark (/>*) in the open box 口 )(
when you have obtained applicable material and completed the steps for sampling and analytical
1. Calibration of Air Sampling Pump
Multi- or high-flow air sampling pump
37-mm, 5.0-|im pore size PVC filter with cellulose support pad in assembled three-stage plastic
Two 2- to 3-ft lengths of '/4-in. i.d. flexible hose
Manual or electronic friction I ess bubble-tube calibrator
Soap solution (depending on calibrator used)
Stopwatch (if manual calibrator is used)
Calibration data form (Figure 4.6)
2, Sampling for Total Particulate
Antistatic device and electrobalance to prepare (pre-weigh) filter for sample collection
Pre-weighed 37-mm, 5.0-gm pore size PVC filter with cellulose support pad in assembled
three-stage plastic cassette
Calibration Data Form:
Low-Flow, High-Flow, and Multi-Flow Air Sampling Pumps
Cellulose cassette bands or tape to secure stages of the cassette (optional)
Multi-flow or high-flow air sampling pump
1 3-ft length of 'A-in, i.d. flexible hose
Cassette adaptors to connect flexible hose to orifice of cassette
Field sampling data form (Figure 4.7)
3. Analysis of Sample for Total Particulate
Electrobalance accurate to >0.001 mg
Laboratory analysis data form (Figure 4.8)
1. Pre-sampling Calibration of Air Sampling Pump
Remove the pump from charger, t urn “ON ” and allow it to operate for 5 min prior to calibr ating.
Complete a calibration form, remembering to record name, location, date, air temperature, air
pressure, pump manufacturer and model, calibration apparatus, times for three trials, and average
flow rate for pre- and post-sampling calibrations.
Obtain a representative sampling medium for use during calibration of the air sampling pump;
this should consist of a 37-mm, 5.0-gm pore size PVC filter (unweighed or weighed) and
cellulose support pad in assembled three-stage plastic cassette.
Insert a cassette adapter into one end of a 2+! to 3-ft length of flexible hose.
Connect the other end of the flexible hose to the air sampling pump.
Connect the adapter end of the flexible hose to the outlet orifice located on the first stage of the
support pad side of the cassette used as the representative sampling medium.
Insert another cassette adapter into one end of another 2+! to 3-ft length of flexible hose.
Connect the adapter end of the second flexible hose to the inlet orifice located on the third stage
or filter side of the cassette used as the representative sampling medium.
Connect the remaining open end of the flexible hose to a manual or electronic frictionless bubbletube calibration device; this constitutes the calibration train.
Aspirate the bubble solution into the calibration device to form a soap film (bubble).
Record the time (T |sec|) it takes the soap film (bubble) to traverse a volume of 500 to 1000 ml.
If a manual bubble-tube is used, calculate the flow rate (Q [1/min]). Otherwise, read the flow rate
directly from the electronic bubble-tube calibrator.
If the flow rate is not 2 1/min ù3# *! adjust the flow control on the pump and repeat calibration
procedure until desired flow rate is achieved.
Once the desired flow rate is achieved, in this example 2 1/min ù3# *! repeat the calibration check
two to three limes and calculate the average pre-sampling flow rate.
Disconnect the pump from the remainder of the calibration apparatus and turn “OFF.” The cali
brated air sampling pump is ready for use.
2. Prepare Sampling Media
Complete a laboratory analysis data form, remembering ...
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