IP-10A METHOD UPDATE
Year 2004
www.skcinc.com
This method update has been written by SKC as a guideline for users. The sampling apparatus
specified in this SKC update reflects new technology that may not have been available at the time
of the original publication. This method update by SKC has not been officially endorsed or
approved by U.S. EPA.
DETERMINATION OF FINE PARTICULATE MATTER IN INDOOR
AIR USING SIZE-SPECIFIC IMPACTION
� Personal Environmental Monitor (PEM) with Leland Legacy
Pump
� Sioutas Personal Cascade Impactor Sampler (PCIS) with
Leland Legacy Pump
Publication No. 1660 Issue 0601
IP-10A Method Update
By SKC Inc.
Year 2004
www.skcinc.com
DETERMINATION OF FINE PARTICULATE MATTER IN INDOOR
AIR USING SIZE-SPECIFIC IMPACTION
1. Scope
1.1 The term fine particulate matter (PM) is typically used to describe airborne
solid particles and liquid droplets less than 2.5 microns in aerodynamic diameter.
Fine PM results from a variety of sources including fuel combustion from power
plants, industrial facilities, and motor exhaust. Fine particles can also be formed
in the atmosphere when combustion gases such as sulfur dioxide and nitrogen
oxides are chemically transformed into particles.
1.2 Since the Compendium of Methods for the Determination of Air Pollutants in
Indoor Air was first published in April 1990, the focus on particulate matter has
grown in the research and regulatory communities (1). Specifically, fine
particulate matter has become a national concern because it can penetrate deep
into the lung causing significant health effects. Health effects include an increase
in respiratory symptoms and related hospital visits, aggravated asthma, chronic
bronchitis, and premature death. Those most at risk include the elderly,
individuals with preexisting heart or lung disease, and children, particularly those
with asthma.
1.3 Several studies have reported that stationary monitors are poor estimators of
personal exposure to PM. Differences in one’s activities combined with the
localized nature of certain particle types can cause large interpersonal sample
variability. Therefore, to better assess the effect of PM exposures on the health
of individuals it is necessary to sample the indoor microenvironment. Indoor
microenvironmental (personal) samples can be used to better characterize the
mass, size, and chemical composition of PM pollutants along with their impact on
health. (2-3)
1.4 The collection of meaningful sampling data in the indoor microenvironment
has been hampered by the available technology. Size-selective personal
sampling devices that measure PM have been limited to single-stage impactors
such as the Personal Environmental Monitor (PEM) with an impactor cut-point of
either 2.5 or 10 microns. As such, the PEM does not provide information on the
IP-10A Method Update by SKC Inc. Page 2
complete size distribution of PM pollutants. Similarly, the status of sampling
pump technology has created obstacles to personal sample collection of indoor
PM. Typical indoor PM concentrations dictate the need for high flow rates and
long run times to collect enough sample for analysis. (4-6). However, to be worn
comfortably by a person for an extended period, the pump has to be of a
reasonable size and weight and produce a low noise level.
1.5 To address the need for complete characterization of PM pollutants indoors,
the Sioutas Personal Cascade Impactor Sampler (PCIS) has been developed. (7)
This miniaturized cascade impactor, hereafter referred to as the Sioutas
Impactor, consists of four impaction stages, followed by an after-filter. Its Teflon®
impaction substrates permit gravimetric analysis of PM mass or chemical
analysis of PM constituents. The Sioutas Impactor can be connected to the
participant’s lapel and used with a new high-efficiency pump, the Leland
Legacy®, which provides the required 9 L/min flow rate for 24 hours.
1.6 If, however, a single-stage impactor is sufficient for the study, the Leland
Legacy pump can be used at 10 L/min with the PEM (fully described in the 1990
version of Method IP-10A). The Leland Legacy pump provides for improved
analytical sensitivity because 24-hour sampling is possible using the PEM for
size-specific sample collection.
1.7 This method may involve hazardous materials, operations, and equipment.
This method does not purport to address all the safety problems associated with
its use. It is the responsibility of whoever uses this method to consult and
establish appropriate safety and health practices and to determine the
applicability of regulatory limitations prior to use.
2. Applicable Documents
2.1 ASTM Standards
D1356 Definitions of Terms Relating to Atmospheric Sampling and Analysis
D1605 Sampling Atmospheres for Analysis of Gases and Vapors
D1357 Planning the Sampling of the Ambient Atmosphere
2.2 Other Documents
Compendium of Methods for the Determination of Air Pollutants in Indoor Air
Compendium of Methods for the Determination of Inorganic Compounds in
Ambient Air
U.S. Environmental Protection Agency Technical Assistance Documents
Laboratory Studies for Monitoring Development and Evaluation
IP-10A Method Update by SKC Inc. Page 3
3. Summary of Method
3.1 For determining fine particulate matter in indoor air, two sampling devices will
be described along with a new high-efficiency pump that allows 24-hour sampling
with either device. The two sampling devices are the Personal Environmental
Monitor (PEMâ„?) and the Sioutas Personal Cascade Impactor. Both sampling
devices operate on the principal of impaction. The PEM is a single-stage
impactor with an after-filter; the Sioutas Impactor is a 4-stage impactor with an
after-filter.
3.2 With the PEM, particle-laden air is accelerated through a number of nozzles
and the exiting jets impinge upon a ring. The particles larger than the designated
cut-size impact onto the ring due to inertia. The smaller particles are carried
along in the airstream and are collected on the 37-mm Teflon after-filter. Six
versions of the PEM are available to collect either fine (PM2.5) or coarse (PM10)
particulates at one of three different flow rates: 2, 4, or 10 L/min. This method will
focus on the PEM designed for fine particulates (PM2.5) at 10 L/min using the
Leland Legacy pump for 24-hour sampling.
3.3 The Sioutas Impactor is a miniaturized cascade impactor consisting of four
impaction stages and an after-filter. Particles are separated in the following
aerodynamic particle diameter ranges: <0.25, 0.25-0.5, 0.5-1.0, 1.0-2.5, and 2.5-
10 µm. The Sioutas Impactor operates at a flow rate of 9 L/min.
3.4 A known volume of air is drawn for a measured period of time through either
impaction device to a tared filter or filters.
3.5 Size-specific PM levels are calculated from the weight gain of the filter in
each stage and the total volume of air sampled. The Sioutas Impactor does not
require the coating of filters to minimize particle bounce. Therefore, with this
sampler, chemical species analysis can also be performed on the filter-collected
PM following Chapter IO-3 in the Compendium of Methods for the Determination
of Inorganic Compounds in Ambient Air.
4. Significance
4.1 There is a need to obtain meaningful exposure data for PM in the indoor
environment to better assess health effects in epidemiological studies. Indoor PM
levels are affected by a number of indoor and outdoor sources and there is high
interpersonal variability in exposures. To meet this need, sampling pumps must
be suitable for sampling in the microenvironment and must provide extended run
times up to 24 hours to increase the amount of PM collected.
IP-10A Method Update by SKC Inc. Page 4
4.2 Particle size and particle components such as sulfate and acidity are
important factors when studying the adverse health effects and increased
mortality from PM exposures. Therefore, sample collection devices should allow
for the calculation of particulate mass as well as for the identification of particle
size and chemical species.
4.3 For these reasons, it is imperative that a sampling protocol addressing the
sampling and analysis of speciated particulate matter in indoor air be developed.
5. Definitions
Note: Definitions used in this document and any user-prepared Standard
Operating Procedures (SOPs) should be consistent with ASTM Method D1356.
All pertinent abbreviations and symbols are defined within this document at point
of use.
5.1 Particulate matter-a generic classification in which no distinction is made on
the basis of origin, physical state, and range of particle size. (The term
“particulate� is an adjective, but it is commonly used as a noun.)
5.2 Dust-dispersion aerosols with solid particles formed by comminution or
disintegration without regard to size. Typical examples include: (1) natural
minerals suspended by the action of wind; and (2) solid particles suspended
during industrial grinding, crushing, or blasting.
5.3 Smokes-dispersion aerosols containing both liquid and solid particles formed
by condensation from supersaturated vapors. Generally, the particle size is in the
range of 0.1 to 10 µm. A typical example is the formation of particles due to
incomplete combustion of fuels.
5.4 Fumes-dispersion aerosols containing liquid or solid particles formed by
condensation of vapors produced by chemical reaction of gases or sublimation.
Generally, the particle size is in the range of 0.01 µm to 1 µm.
5.5 Mists-suspension of liquid droplets formed by condensation of vapor or
atomization; the droplet diameters exceed 10 µm and, in general, the particulate
concentration is not high enough to obscure visibility.
5.6 Primary particles (or primary aerosols)-dispersion aerosols formed from
particles that are emitted directly into the air and that do not change form in the
atmosphere. Examples include windblown dust and ocean salt spray.
5.7 Secondary particles (or secondary aerosols)-dispersion aerosols that form in
the atmosphere as a result of chemical reactions. A typical example is sulfate
ions produced by photochemical oxidation of SO2.
IP-10A Method Update by SKC Inc. Page 5
5.8 Particle-any object having definite physical boundaries in all directions,
without any limit with respect to size. In practice, the particle size range of
interest is used to define “particle.� In atmospheric sciences, “particle� usually
means a solid or liquid subdivision of matter that has dimensions greater than
molecular radii (~10 nm); there is also not a firm upper limit, but in practice, it
rarely exceeds 1 mm.
5.9 Coarse and fine particles-these two fractions are usually defined in terms of
the separation diameter of a sampler. Coarse particles are those with diameters
of 2.5 µm to 10 µm and the fine particles are those with diameters less than
2.5 µm.
Note: Separation diameters other than 2.5 µm have been used.
6. Method Limitations and Limits of Detection
6.1 PEM
6.1.1 The PEM’s limit of detection (LOD) is a function of the weighing room
environment and the precision of the microbalance used to perform mass
measurements.
6.1.2 The 1990 version of this method suggested a minimum weight of
20 micrograms (µg) of particles on the filter using the PEM and a maximum
loading of 600 micrograms/cm2.
6.2 Sioutas Impactor
6.2.1 Particle loading tests indicated that each Sioutas Impactor stage could
retain its collection efficiency for particle loadings up to 3.16 mg for fine PM and
700 µg for coarse PM. The Sioutas Impactor also showed the ability to preserve
labile species during sampling, which is highly desirable as a significant fraction
of fine particles is associated with such species.
7. Apparatus Description
7.1 Personal Environmental Monitor (PEMâ„?)
7.1.1 A schematic diagram of the PEM is shown in Figure 1. The sampler weighs
48 grams (1.7 oz) and consists of three basic sections: an inlet nozzle cap,
impaction ring assembly, and base.
IP-10A Method Update by SKC Inc. Page 6
7.1.2 Inlet nozzle cap- The PEM designed for PM2.5 collection at 10 L/min has
10 nozzles located in a circle along the outer edge of the nozzle cap through
which the aerosol enters the sampler.
7.1.3 Impaction ring assembly-This section serves as both an impaction surface
and a clamping ring for the after-filter. Aerosol passing through the inlet nozzles
impacts onto an annular disk of porous material cemented onto the ring that
clamps the after-filter to the base. To reduce particle bounce, oil is applied to the
impaction ring. The airstream containing the remaining smaller particles flows
through the circular opening in the center of the impaction plate.
7.1.4 Base-The base houses a stainless steel support screen used to support the
after-filter. The force applied by attaching the nozzle cap clamps the after-filter to
the support screen to form an airtight seal between the filter and base. The base
also has an exit plenum and outlet tube that connects by tubing to the pump.
7.1.5 Filter-A 37-mm, 2.0 µm pore size PTFE (Teflon®) filter with PMP support
ring is used as the filtration medium. It is supported by a stainless steel screen
that is supplied with the PEM.
Note: Back pressure on Teflon filters can vary within the same lot.
7.1.6 Flow Calibration Attachment-A special attachment known as the Flow
Calibration Cap provides for a single inlet to the PEM to which a flowmeter can
be attached. The Flow Calibration Cap is pressed onto the inlet nozzle cap of the
PEM. A flowmeter is attached to the ½-inch diameter inlet tube on the top of the
calibration cap. An optional fitting is attached to the side of the Flow Calibration
Cap for purposes of attaching a pressure gauge if there is a large pressure drop
across the flowmeter. Under normal operation, however, the pressure need not
be measured and the pressure tap can be closed off.
7.2 Sioutas Personal Cascade Impactor
7.2.1 The Sioutas Impactor is constructed of aluminum and weighs 159 grams
(5.6 oz). An exploded view of the sampler is shown in Figure 2. It consists of an
inlet plate, 4 accelerator plates that have slits that perform the size selection,
4 collector plates that hold the impaction substrates, and an outlet plate that
holds the after-filter. The device is held together by two thumbnuts on threaded
studs.
7.2.2 The outlet plate houses the 37-mm after-filter, which is supported by a
screen and secured in place by a compression ring and O-ring all supplied with
the Sioutas Impactor.
IP-10A Method Update by SKC Inc. Page 7
7.2.3 A collector plate rests on top of the outlet plate such that the indicated
marks are in alignment. A 25-mm filter that serves as the impaction substrate is
then placed in the collector plate and it is held in place with a filter retainer ring.
7.2.4 The appropriate accelerator plate is then placed on top of the collector plate
in the proper alignment. These steps are repeated until all collector plates with
substrates and accelerator plates are in place. Finally, the inlet plate is put in
place on top of the sampler and the thumbnuts are tightened to secure the
device.
7.2.5 Filters and Substrates-A 37-mm, 2.0 µm pore size PTFE (Teflon®) filter with
PMP support ring is used as the after-filter in the outlet plate. The recommended
impaction substrates on the collector plates are either 25-mm, 0.5 µm PTFE
filters with PTFE support or 25-mm, 3.0 µm PTFE filters with PMP support ring.
Note: Back pressure on Teflon filters can vary within the same lot.
7.2.6 Flow Calibration- The inlet and outlet plates have �-inch OD, ¼-inch ID
fittings to which flexible tubing can be attached. The outlet fitting is connected to
the sampling pump. The inlet fitting is connected to the flowmeter for flow
calibration.
7.3 Leland Legacy Sampling Pump
7.3.1 Pump -This method is written for use with the PEM designed to collect
PM2.5 at 10 L/min or with the Sioutas Impactor at 9 L/min. The Leland Legacy
pump will provide constant flow (±3%) with either sampling device for 24 hours or
more (see Figure 3). If during sampling the pump flow rate drops by more than
5%, the pump will stop but retain in memory all valid sampling data prior to the
flow fault. In addition, upon fault shutdown, the pump will automatically make up
to 10 attempts to restart itself and run at the flow rate originally set.
7.3.2 Electronics-The pump electronics feature an internal flow sensor that
measures flow directly and acts as a secondary standard, crystal-controlled real-
time clock, sensors that automatically maintain flow calibration by compensating
for differences in temperature and atmospheric pressure during sampling, a liquid
crystal display (LCD), battery status indicator, and low battery switch-off.
7.3.3 The three-button controls can be used to program the pump and to scroll
through the recorded data. Recorded values include start date and time; stop
date and time; total sample time; flow rate; sample volume; temperature; and
atmospheric pressure. Programming options include a security/tamper-resistance
feature. To change any sampling parameter, the user must enter a security code
IP-10A Method Update by SKC Inc. Page 8
(button sequence is the same for all the pumps). For ultimate tamper resistance,
the user can set a lockout option through the optional DataTrac® software
program.
7.3.4 Automation-The DataTrac software program (purchased and installed
separately) affords the user ultimate flexibility in pump scheduling and complete
recordkeeping capabilities. Through the “Pump Scheduler� window shown in
Figure 4, the user can program up to 100 sampling intervals with defined start
and stop times and flow rates. Through the “Sample Set-up� window, the user
can record all sample identification information. DataTrac software also records
critical pump parameters such as run time, flow rate, and air volume and notes
any changes in pump operational status such as flow fault or an exhausted
battery. This pump history can be saved to a file or printed.
7.3.5 Flow Calibration Options- The pump will display the flow rate in L/min on
the LCD as measured by the internal flow sensor. Calibration can be verified by a
primary flow standard and adjusted based on the primary standard reading.
Alternatively, the CalChek® option can be utilized. With this option, the pump and
a DryCal® DC-Lite primary standard (Bios International, Pompton Plains, NJ)
communicate directly and the pump adjusts the flow until the displayed values of
both agree.
Note: Use PEM Calibration Cap (SKC Cat. No. 761-202) designed specifically
for the PEM.
7.4 Cahn Microbalance
7.4.1 The Cahn Model 30 balance is capable of weighing up to 3.5 g with an
accuracy of ± 0.5 µg. It operates on the principle of balancing the sample with
torque motor input. The electric current flowing in the torque motor produces an
equal and opposite force on the balance beam when the beam is at the reference
position, identified by a photocell detection system. The current is directly related
to the sample weight through the calibration process.
7.4.2 The same analytical microbalance and weights must be used for weighing
filters before and after sample collection.
IP-10A Method Update by SKC Inc. Page 9
7.5 Weighing Room Environment
The weighing room should be a temperature- and relative humidity-controlled
environment. Temperature should be maintained within the range of 17 to 23oC.
Relative humidity should be maintained between 38% and 42%. Weekly strip
chart recordings of temperature and humidity should be maintained on a
hygrothermograph. Temperatures should be read from a calibrated maximum-
minimum thermometer and relative humidity should be calculated from a
calibrated motor aspirated psychrometer. The weighing area should be cleaned
with paper towels and deionized distilled water each day before weighing.
Forceps should be cleaned once a week with detergent in a sonic bath and then
rinsed in deionized distilled water. Approximately once a month, the balance
chamber and pans should be cleaned with diluted ammonium hydroxide and
each cleaning should be noted in the weighing room logbook. Filters, weights,
and pans should be handled only with non-serrated tip forceps (SKC Cat. No.
225-8371). The Cahn balance should be left on continuously because it requires
six hours to warm up for stable operation. Polonium 210 alpha sources should be
replaced at one-year intervals from date of manufacture. The replace by date
should be engraved on the source by the manufacturer, and noted in the
weighing room logbook. The filters should be conditioned in the weighing room
for at least 24 hours before they are weighed. Each filter should be passed over
a deionizing unit before weighing.
8. Apparatus Listing
8.1 Personal Environmental Monitor (PEM)
8.1.1 Sampler-MSP Corporation, 5910 Rice Creek Parkway, Suite 300,
Shoreview, MN (SKC Cat. No. 761-203B) with optional Flow Calibration Cap
(SKC Cat. No. 761-202) and Clamping Device (SKC Cat. No. 761-201).
8.1.2 Filter- 37-mm, 2 µm nominal pore diameter PTFE membrane filter disk with
PMP support ring (SKC Cat. No. 225-1709 or equivalent).
Note: Back pressure on Teflon filters can vary within the same lot.
8.1.3 Pump-Leland Legacy Pump, SKC Inc., 863 Valley View Road, Eighty Four,
PA (SKC Cat. No. 100-3000NULK or equivalent).
8.1.4 Pump Flowmeter-DryCal DC-Lite, Bios International, 230 West Parkway,
Unit 1, Pompton Plains, NJ (SKC Cat. No. 717-05 or equivalent).
8.1.5 Analytical Microbalance-refer to Section 7.4
IP-10A Method Update by SKC Inc. Page 10
8.2 Sioutas Personal Cascade Impactor
8.2.1 Sampler-SKC Inc., 863 Valley View Road, Eighty Four, PA (SKC Cat. No.
225-370)
8.2.2 After-filter-37-mm, 2 µm nominal pore diameter PTFE membrane filter disk
with PMP support ring (SKC Cat. No. 225-1709 or equivalent).
Note: Back pressure on Teflon filters can vary within the same lot.
8.2.3 Collection Substrate-25-mm, 0.5 µm nominal pore diameter PTFE
membrane filter disk (SKC Cat. No. 225-1708 or equivalent).
8.2.4 Pump-Leland Legacy Pump, SKC Inc., 863 Valley View Road, Eighty Four,
PA (SKC Cat. No. 100-3000NULK or equivalent).
8.2.5 Pump Flowmeter-DryCal DC-Lite, Bios International, 230 West Parkway,
Unit 1, Pompton Plains, NJ (SKC Cat. No. 717-05 or equivalent).
8.2.6 Analytical Microbalance-refer to Section 7.4
9. Filter Preparation
9.1.1 All filters are conditioned in the balance room for at least 24 hours before
initial or final weighing to reduce the humidity effects on the filter weights.
9.1.2 A Cahn microbalance with electronic data transfer capability should be
used to weigh the filters and collection substrates used in the samplers. With this
microbalance, a portable computer can be connected through a serial port. Filter
numbers are printed in barcode and assigned to filter containers. In operation,
the filter numbers are scanned with a barcode reader and the filter placed on the
balance pan. A key is then pressed on the computer keyboard to indicate that the
filter is in position for weighing. The computer sends the balance a request to
weigh. The balance responds with weight and stability code. The operator is
signaled by a tone and a message on the computer screen when weighing is
complete. The operator then removes the filter and places it back in its container.
The process is repeated for each filter to be weighed. The initial weight, time, and
data are written to the data file by the computer.
9.1.3 After the filter has been used, it should be transported back to the
laboratory in a suitable container such as the SKC Filter-Keeper (SKC Cat. No.
225-8301/2) for conditioning and final weighing. The weighing procedure is the
same as for initial weighing. The computer will check the data file for the initial
IP-10A Method Update by SKC Inc. Page 11
weight entry. The final weight will be matched with the initial weight for that filter
number in the data file. The computer subtracts the initial weight from the final
weight to determine the particle load which is used to calculate the particulate
concentration in µg/m3 at each sampler location. After weighing, the filters are
carefully returned to suitable containers for archiving or further analyses.
10. Sampler Preparation
10.1 Preparation of PEM
10.1.1 The PEM should be disassembled by removing the two screws holding
the nozzle cap to the base. After the screws are removed, the nozzle cap should
be lifted up to clear the impaction ring assembly. The impaction ring assembly is
removed exposing the after-filter housing. If used previously, the sampler should
be cleaned before reuse. The nozzle cap can be cleaned by rinsing with
isopropyl alcohol. The particles on the impaction ring should be removed by
scraping the surface with a knife or razor blade. Oil can be removed from the ring
by placing it in a soap solution or a solvent such as cyclohexane followed by
complete rinsing and drying.
10.1.2 The impaction ring must be coated with a light machine oil to eliminate
particle bounce. The oil can be applied to the ring by using an eyedropper to
place drops evenly around the ring. Fourteen drops is the maximum amount that
the impaction ring will hold. Excess oil can be removed by touching a tissue to
the porous surface.
10.1.3 To assemble the PEM, place a filter on the filter support screen in the
base and set the impaction ring assembly on the filter. Place the nozzle cap over
the impaction ring assembly and replace the two screws. An optional Clamping
Device (SKC Cat. No. 761-201) is available to ensure that the nozzle cap is
clamped parallel to the base and that the correct clamping force has been
applied.
10.1.4 After assembly, attach flexible tubing to the outlet fitting of the sampler
and to the inlet of the Leland Legacy pump.
10.1.5 The PEM Flow Calibration Cap (SKC Cat. No. 761-202) provides for a
single inlet to the PEM to which a flowmeter can be attached. The Flow
Calibration Cap is pressed onto the nozzle cap of the PEM. The flowmeter is
attached to the ½-inch diameter inlet tube on the top of the device.
10.1.6 The recommended flow rate for the PEM specified in this method is
10 L/min. Start the pump, adjust the flow to 10 L/min, and run the pump for a
minimum of 5 minutes to stabilize the flow. Adjust pump flow until 10 L/min
IP-10A Method Update by SKC Inc. Page 12
appears on the flowmeter. Record the initial flow rate as indicated by the flow-
meter. Disconnect the flowmeter and Flow Calibration Cap.
10.1.7 Place the pump and PEM in the desired sample location. Initiate sampling
by turning on the pump and recording all pertinent sampling details.
10.1.8 At the end of the sampling period, turn off the pump and document all
pertinent sampling details including the sample time displayed on the pump LCD.
Repeat the flow calibration as indicated in 10.1.5 and 10.1.6. The flow rate for the
overall sample period will be the average of the flow rates determined in the pre-
and post- flow calibration. The pre- and post- flow calibration values should agree
within ± 5%. Multiply the flow rate by the sample time to determine the air volume
for individual samples.
10.2 Preparation of Sioutas Impactor
10.2.1 The Sioutas Impactor should be disassembled by loosening the two
thumbnuts and removing all stages. To remove O-rings, align the head of a small
flat-head screwdriver with the notch in the inner wall of the plate. Gently lift the O-
ring up and out. Wash parts in water with detergent or in isopropyl alcohol. Parts
may also be cleaned in an ultrasonic bath. Rinse and dry all parts thoroughly with
compressed air if available or airdry in a clean environment. Inspect all
accelerator plates by holding them up to a light to ensure that none of the
impaction slits are clogged. Impaction slits may be cleaned with compressed air.
10.2.2 In a clean environment, assemble the Sioutas Impactor from outlet to inlet
as follows: (1) insert the 37-mm after-filter into the outlet plate and replace the
compression ring and O-ring; (2) place a collector plate on top of the outlet plate
and align the marks; (3) use forceps to place a 25-mm filter in the collector plate,
place a filter retainer on top of the filter, and press retainer down firmly; (4) place
the designated accelerator plate on top of the collector plate and align the marks;
(5) repeat steps (3) and (4) for all stages; (6) put inlet plate in place; and (7)
replace thumbnuts.
10.2.3 Using flexible tubing, connect the outlet of the Sioutas Impactor to the inlet
of a Leland Legacy pump or other pump capable of maintaining a constant
9 L/min flow rate for up to 24 hours. Connect the inlet of the Sioutas impactor to
the outlet of a flowmeter such as the DryCal DC-Lite (SKC Cat. No. 717-05) or
other primary flowmeter capable of measuring 9 L/min.
10.2.4 The recommended flow rate for the Sioutas Impactor is 9 L/min. Start the
pump, adjust the flow to 9 L/min, and run the pump for a minimum of 5 minutes to
stabilize the flow. Adjust pump flow until 9 L/min appears on the flowmeter.
IP-10A Method Update by SKC Inc. Page 13
Record the initial flow rate as indicated by the flowmeter. Disconnect the
flowmeter.
10.2.5 Place the pump and Sioutas Impactor in the desired sample location.
Initiate sampling by turning on the pump and recording all pertinent sampling
details.
10.2.6 At the end of the sampling period, turn off the pump and document all
pertinent sampling details including the sample time displayed on the pump LCD.
Repeat the flow calibration as indicated in 10.2.4. The flow rate for the overall
sample period will be the average of the flow rates determined in the pre- and
post- flow calibration. The pre- and post- flow calibration values should agree
within ± 5%. Multiply the flow rate by the sample time to determine the air volume
for individual samples.
11. Filter Removal and Transport
11.1.1 After sampling with either the PEM or the Sioutas Impactor, the filters
should be carefully removed from the device for weighing and/or other analyses.
The filters should be handled with the aid of tweezers to avoid sample loss. Do
not turn filters upside down. If transporting samples to an offsite laboratory, place
filters in marked, sealed containers for transport such as the SKC Filter-Keeper
(SKC Cat. No. 225-8301/2).
11.1.2 For each set of samples, submit a blank sample. The filters to be used as
blanks are handled in the same manner as the samples except that no air is
drawn through them. Label these as blanks.
11.1.3 As the filters are unpacked in the laboratory, the date received and the
condition of the filters should be noted on the accompanying Field Data Sheet
and laboratory logbook.
11.1.4 Filters should be placed in an environmentally controlled weighing room
and allowed to equilibrate for a minimum of 24 hours. Final weighing of the filters
must be performed on the same balance as the original weighing using the same
standard operating procedures.
IP-10A Method Update by SKC Inc. Page 14
12. Calculation
12.1 Mass of particles found on the sample filter:
Ms = (m2- m1) - m3
Where:
Ms= mass found on the sample filter
M1= tare weight of the clean filter before sampling, µg
M2=the weight of the sample-containing filter, µg
M3=the mean value of the net mass change found on the blank filters, µg
Note: The blank filters must be subjected to the same equilibrium conditions.
12.2 The sampled volume is:
Vs= Q x t/1000
Where:
Vs=volume of the air sampled, m3
Q= average flow rate of air sampled, L/min
T= sampling time, min
1000=conversion from L to m3
Note: There are no temperature or pressure corrections for changes in sampled
volume since the flow calibration is typically performed with the impactor in place
at the sampling location. In addition, the Leland Legacy pump will compensate
for any additional changes in temperature and atmospheric pressure.
12.3 The concentration of the particulate matter in the sampled air is expressed
in micrograms/m3.
C = Ms/Vs
Where:
C= mass concentration of particulate matter, µg/m3
Ms=mass found on the sample filter, µg
Vs= volume of air sampled, m3
IP-10A Method Update by SKC Inc. Page 15
13. Method Safety, Performance Criteria, and Quality Assurance
13.1 Method Safety
13.1.1 This procedure may involve hazardous materials, operations, and
equipment. This method does not purport to address all the safety concerns
associated with its use. It is the user’s responsibility to establish appropriate
safety and health practices and to determine the applicability of regulatory
limitations prior to the implementation of this procedure. This should be part of
the user’s SOP manual.
13.2 Performance Criteria and Quality Assurance
13.2.1 SOPs should be generated by the users to describe and document the
activities in their laboratory including: assembly, calibration, operation of the
samplers, pumps, and other equipment; sample transport; and data recording
and processing.
13.3 Quality Assurance Program
13.3.1 The user should develop, implement, and maintain a quality assurance
program to ensure that the sampling system is operating properly and collecting
accurate data. Established protocols for calibration, operation, and maintenance
should be conducted on a regularly scheduled basis and should be part of the
quality assurance program.
14. References
1. U.S. Environmental Protection Agency, Compendium of Methods for the
Determination of Air Pollutants in Indoor Air, Atmospheric Research and
Exposure Assessment Laboratory, Research Triangle Park, NC, April 1990.
2. Clayton, D., Perritt, R., Pellizzari, E., Thomas, K., Whitmore, R., Wallace, L.,
Ozkaynak, H., Spengler, J., “Particle Total Exposure Assessment Methodology
(PTEAM) Study: Distributions of Aerosol and Elemental Concentration in
Personal, Indoor, and Outdoor Samples in a Southern California Community,�
Journal of Exposure Analysis and Environmental Epidemiology, 3(2), 1993, pp.
227-250.
3. Conner, T., Williams, R., “Individual Particle Analysis of Personal Samples
from the 1998 Baltimore Particulate Matter Study,� Proceeding of the American
Association for Aerosol Research Particulate Matter Meeting, March 31-April 4,
2003, Pittsburgh, Pennsylvania.
IP-10A Method Update by SKC Inc. Page 16
4. Morandi, M., Stock, T., and Contant, C., “A Comparative Study of Respirable
Particulate Microenvironmental Concentrations and Personal Exposures,�
Environmental Monitoring and Assessment, 10(2), 1988, pp. 105-122.
5. Singh, M., Misra, C., Sioutas, C., “Field Evaluation of a Personal Cascade
Impactor Sampler (PCIS),� Proceeding of the American Association for Aerosol
Research Particulate Matter Meeting, March 31-April 4, 2003, Pittsburgh,
Pennsylvania.
6. Spengler, J., Treitman, R., Tosteson, T., Mage, D., Soczek, M., “Personal
Exposures to Respirable Particulates and Implications for Air-pollution
Epidemiology,� Environmental Science and Technology, 19, 1985, pp. 700-707.
7. Misra, C., Singh, M., Shen, S., Sioutas, C., Hall, P., “Development and
Evaluation of a Personal Cascade Impactor Sampler (PCIS),� Journal of Aerosol
Science, 33, 2002, pp. 1027-1047.
IP-10A Method Update by SKC Inc. Page 17
Spanner Machine Screws
Nozzle Cap
Nozzle Cap Gasket
Porous Stainless Steel
Impaction Ring
Impaction Ring Support
2.5 µm, 10 L/min PEM, assembled
Stainless Steel
Support Screen
Base
Outlet Tube
Figure 1. Schematic Diagram of Personal Environmental Monitor (PEMâ„?)
IP-10A Method Update by SKC Inc. Page 18
Thumb Nuts
Clip
Inlet Plate
Accelerator Plate A
Collector Plate
O-ring
Accelerator Plate B
Compression Ring
Collector Plate Spacer Ring
Screen
Accelerator Plate C
Collector Plate
Outlet Plate and
After-filter Housing
Accelerator Plate D
Collector Plate
Exploded View of Sioutas Impactor
Outlet Plate
Outlet plate and After-
filter Housing
Threaded Studs
Figure 2. Exploded View of Sioutas Personal Cascade Impactor
IP-10A Method Update by SKC Inc. Page 19
Inlet Port
Flashing LED Run with protective filter
Indicator
Battery
Status Icon
Liquid Crystal
Display (LCD)
Keypad
with large operating
buttons
Li-Ion
Battery
Pack
For 24-
hour run
times
(included) Soft Rubber Over-molding
protects against damage
Not shown:
Beltclip (back)
Battery Charging Jack
(top)
Computer Interface
Port (top)
Sioutas Personal Cascade Impactor in
Sampling Train.
Figure 3. Leland Legacy Sample Pump
IP-10A Method Update by SKC Inc. Page 20
Figure 4. Pump Scheduler Window in DataTrac Software for Leland Legacy Pump
IP-10A Method Update by SKC Inc. Page 21
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