ASTM D8358-21

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D8358 − 21
Standard Guide for
Assessment and Inclusion of Wall Deposits in the Analysis
of Single-Stage Samplers for Airborne Particulate Matter
This standard is issued under the fixed designation D8358; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 Many methods for sampling airborne particulate matter
ization established in the Decision on Principles for the
entail aerosol collection on a substrate (typically a filter)
Development of International Standards, Guides and Recom-
housed within a container (or holder), the whole apparatus
mendations issued by the World Trade Organization Technical
being referred to as an aerosol sampler. In operation, the
Barriers to Trade (TBT) Committee.
sampler allows a vacuum (pressure below ambient or room air
pressure) to be applied to the rear of the substrate so that
2. Referenced Documents
sampled air will pass through the substrate, leaving collected
2.1 ASTM Standards:
particles on the substrate for subsequent analysis. The sampler
D1356Terminology Relating to Sampling and Analysis of
may also protect the substrate, while the opening (orifice) of
Atmospheres
the container may further play some role in determining what
D4185Test Method for Measurement of Metals in Work-
size range(s) of particles approach the collection substrate
placeAtmospheres by FlameAtomicAbsorption Spectro-
(size-selective sampling).
photometry
1.2 All particles entering the container orifice are consid-
D4532Test Method for Respirable Dust in Workplace At-
ered part of the sample, unless stated otherwise in the method,
mospheres Using Cyclone Samplers
but not all particles are necessarily found on the substrate after
D6061Practice for Evaluating the Performance of Respi-
sampling (1). Particlesmaybedepositedontheinnerwallsof
rable Aerosol Samplers
thesamplerduringsamplingormaybedepositedontheinside
D6062GuideforPersonalSamplersofHealth-RelatedAero-
walls of the sampler or on the orifice plug or cap following
sol Fractions
transportation (2). These particles are often loosely referred to
D6552Practice for Controlling and Characterizing Errors in
as wall deposits. This guide presents background on the
Weighing Collected Aerosols
importance of these wall deposits and offers procedures by
D6785TestMethodforDeterminationofLeadinWorkplace
which these deposits can be assessed and included in the
Air Using Flame or Graphite FurnaceAtomicAbsorption
sample.
Spectrometry
1.3 Wall deposits may also occur in multi-stage samplers
D7035Test Method for Determination of Metals and Met-
(forexample,cascadeimpactors),butthisguidedoesnotcover
alloids in Airborne Particulate Matter by Inductively
such samplers.
Coupled Plasma Atomic Emission Spectrometry (ICP-
AES)
1.4 The values stated in SI units are to be regarded as
D7439Test Method for Determination of Elements in Air-
standard. No other units of measurement are included in this
borne Particulate Matter by Inductively Coupled Plasma-
standard.
–Mass Spectrometry
1.5 This standard does not purport to address all of the
D7948Test Method for Measurement of Respirable Crystal-
safety concerns, if any, associated with its use. It is the
line Silica in Workplace Air by Infrared Spectrometry
responsibility of the user of this standard to establish appro-
NOTE 1—Other standards under the jurisdiction of ASTM Committee
priate safety, health, and environmental practices and deter-
D22 on Air Quality, including standards that are not the direct responsi-
mine the applicability of regulatory limitations prior to use.
bility of Subcommittee D22.04 on Workplace Air Quality, may also be
affected by this guide and should be considered on a case-by-case basis.
This guide is under the jurisdiction of ASTM Committee D22 on Air Quality
and is the direct responsibility of Subcommittee D22.04 on WorkplaceAir Quality.
Current edition approved Jan. 1, 2021. Published February 2021. DOI: 10.1520/ For referenced ASTM standards, visit the ASTM website, www.astm.org, or
D8358-21. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
The boldface numbers in parentheses refer to a list of references at the end of Standards volume information, refer to the standard’s Document Summary page on
this standard. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D8358 − 21
2.2 Other Standards: ciently efficient and reproducible to meet the expanded uncer-
ISO 7708Air quality — Particle size fraction definitions for tainty requirements of the overall sampling and analytical
health-related sampling method.Intheabsenceofapublishedstandardmethoditisthe
EN 13205Workplace exposure — Assessment of sampler responsibility of those collecting samples and the analytical
performanceformeasurementofairborneparticleconcen- laboratory to review the validation data and assess the fitness-
trations (in four parts) for-purpose of the procedure.
5. Significance and Use
3. Terminology
5.1 The following is a non-exclusive list of standards to
3.1 Definitions—For definitions of terms used in this
which this guide applies: Guide D6062; Test Methods D4185,
standard, refer to Terminology D1356.
D4532, D6785, D7035, D7439, D7948; and Practices D6061
3.1.1 wall deposit, n—particles which have entered the
and D6552.
container (holder) of an air sampler but which are found
5.2 The applicability of this guide to other standards under
elsewhere than on or in the principal particle collection
the jurisdiction of ASTM Committee D22, but not the direct
medium (for example, a filter), including on any internal
responsibility of Subcommittee D22.04, should be considered
surfaces of the holder or container, such as O-rings and inlet
where analyte entry into the sampler is considered the sample
plugs or covers.
and where analyte adherence to internal sampler surfaces
4. Summary of Guide (“walls”) is likely to scavenge analyte from the collection
substrate.
4.1 Aerosol samplers that are used to collect “total particu-
5.3 Aerosol samplers typically consist of a filter or other
late matter” (TPM), as dictated by the aspiration efficiency of
collection substrate, for example an impaction plate or foam,
the sampler, and samplers that are used to collect “inhalable
supported in a container or holder. The entire device typically
particulate matter” (IPM), as dictated by the ISO 7708 inhal-
is considered an aerosol sampler. The sampling efficiency of
able particle convention, consist of filters housed in containers
the aerosol sampler, that is, the ratio of the concentration
(holders). The design of the holder, normally referred to as a
collectedbythecollectionsubstratetotheundisturbedconcen-
sampler, may be optimized so that aspiration follows the ISO
trationintheair,hasthreecomponents:(1)aspiration(orentry)
7708 inhalable particle convention. All particles passing
efficiency; (2) transport efficiency (depending on design, both
through the orifice of these samplers, particularly where the
from entry “plane” to internal separator and from any internal
orifice is designed for a specific sampling performance, typi-
separator to collection substrate); and (3) penetration (through
cally are considered as part of the sample, unless otherwise
the internal separator). For a sampler of a specific design, the
dictated by the method.
three efficiency components are functions of particle (aerody-
4.2 Samplers that are used to collect the “thoracic” particu-
namic) size and flow rate. The aspiration efficiency also
late fraction, as defined by ISO 7708, or the “respirable”
depends on wind speed and direction, while the sampler’s
particulate fraction, as defined by ISO 7708, have a pre-
angle to the vertical influences both the aspiration efficiency
selector to provide a defined size selection. These samplers
and the transport efficiency. Ideally, when a sampler is de-
may also exhibit wall deposits that could require inclusion for
signed and tested for its sampling performance, or both, it
subsequent analysis.
should first be established what is considered as the collected
4.3 This guide details procedures that have been used to
sample (that is, the deposit on the collection substrate, but also
ensure that all collected particles are assessed in the report of
any deposits on any internal surfaces if these are to be
mass collected, or airborne concentrations calculated from the
analysed).
collected mass.
5.4 Partoftheaerosolenteringasamplerwilldepositonthe
4.4 This guide focuses mainly on samples taken for two
internalsurfacesofthesamplerpriortoreachingthecollection
types of analysis: gravimetric analysis for Particles Not Oth-
substrate. There are number of mechanisms by which this can
erwise Regulated/Specified/Classified (PNOR/S/C), and acid
occur, including bounce from the filter, inertial impaction,
extraction/digestion for metals analysis. However, the prin-
gravitational settling and electrostatic attraction after entry. In
ciplesoftheguideareapplicabletosamplescollectedforother
addition, after sample collection, if the collection substrate is
analyticalprocedures,suchasinorganicacidmistsandorganic
transported while mounted in the sampler, it is possible that
aerosols.
particles originally deposited on the collection substrate may
dislodge during transportation. Such particles can thereby
4.5 Three main methods and some variants for assessing
contribute to deposits on the walls, as well as on the base of
wall deposits are discussed in this guide. The selection of
any cover plate or plug.All particles found elsewhere than on
methods is dictated by the ability of the method to meet data
or in the collection substrate are often loosely termed “wall
quality objectives. Recovery must be validated as being suffi-
deposits.” If the sample of interest entails the entire aspirated
air particulate into the container or holder (sampler), it is
necessary to account for these wall deposits, especially if it
Available from International Organization for Standardization (ISO), ISO
Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
cannot be shown that they should be disregarded.
Switzerland, https://www.iso.org.
5.5 The research underpinning the information in this guide
Available from British Standards Institution (BSI), 389 Chiswick High Rd.,
London W4 4AL, U.K., http://www.bsigroup.com. has arisen partly from studies of inert particles (3, 4), but
D8358 − 21
mostlyfrominvestigationsofmethodsforthedeterminationof facilities (16),walldepositsofendotoxinexceeded40%ofthe
airborne metalliferous particulates (2, 5-15). However, the total sample in 34 % of cassettes and exceeded more than half
issues at hand are also important in sampling airborne organic the total sample in some. In the laboratory study of wood dust
materials, including bacterial endotoxin (16), wood (17), and (17) 85 % of the sample aspirated was found on the cassette
pharmaceutical dusts (18); another relevant study reported
walls.Inthepharmaceuticalindustrystudy (18),averagesof51
results from investigations in thermosetting plastics, wood, %, 62 %, and 72 % of the sample was found on non-filter
paper, and animal breeding (19). Except in the case of very
internal surfaces, depending on compound. Figure 8.2 of
large wood dust particles, there is no evidence to suggest that Aitken and Donaldson (3) provides a graph of mass faction
wall deposited particles are sufficiently different from those
wall deposits of inert particles in the IOM sampler versus
foundonthecollectionsubstratetowarranttheirexclusion (13,
particle size. Although the actual data points are not provided
14).Walldepositsarenotlimitedtoaerosolsamplersforlarger
the median is approximately 18 % and the maximum approxi-
airborne particles but may also be found in samplers for finer
mately55%,inaccordancewiththedatainTable2.Witschger,
particles (20, 21). There may be a justification for excluding
et al., (4) provides similar data, with a maximum wall deposit
wall deposits where the performance of an aerosol sampler
of 50 %. While both these studies were performed in a
tested to EN 13205 shows appropriate compliance with the
laboratory, Lidén, et al., (19) presents averages of 24–37 %
relevant ISO 7708 size-selective convention without their
wall deposits in a range of field samples from non-metal
inclusion.
industries, depending on industry.
5.6 The findings of studies that have been carried out to
5.7 TheGesamtsstaubprobenhame(GSP)inhalablesampler,
assess wall deposits in two commonly used samplers are
and similar metal or plastic versions referred to as a conical
summarizedinTable1andTable2.Acommonlyusedsampler,
inhalable sampler (CIS), has not been the subject of similar
the37-mmclosed-facepolystyrenecassette(CFC),isspecified
extensive investigations of wall deposits. While the GSP met
as the sampler of choice in many U.S. National Institute for
the inhalable convention in a European study without consid-
Occupational Safety and Health (NIOSH) and U.S. Occupa-
ering wall deposits for particles up to 25 µm AED (25), for
tional Safety and HealthAdministration (OSHA) methods (1).
particles up 50 µmAED it under-samples by an average of 21
While the specific methods may not explicitly call for the
% with respect to the IOM sampler (when wall deposits are
recovery and analysis of CFC wall deposits, inclusion of wall
considered in the IOM sampler) (26).Astudy of wall deposits
deposits is called for by both agencies (22). Another widely
ataleadmineconcentratemill (5)showedupto40%(median
used sampler, the Institute of Occupational Medicine (IOM)
24 %) of total aspiration on the walls, while the laboratory
personal inhalable sampler, was specifically developed for the
wood study (17) found an average of 42 %, suggesting that
purpose of collecting the inhalable fraction of aerosol in
wall deposits be considered with this sampler. Other samplers
accordancewithISO7708specifications (23).Walldepositsin
notspecifiedinthispracticemayalsohavewalldeposits;these
this sampler were noted during its development and are
should be evaluated on a case-by-case basis.
specifically included as part of the sample (24), although no
standard protocol has been published for their inclusion other 5.8 No pattern has been discerned that might allow for
than for gravimetric analysis. Side-by-side studies have shown correction factors to be used in any single sampler without
little difference between these two samplers when used to introducing too great an uncertainty into the result (1, 12)).
collect aerosol in metals industries (12), provided they are Therefore,itisnecessarytoaccountforthewalldepositsinall
analyzedbythesameprocedure(thatis,filteronlyorfilterplus cases where the sample is meant to include the total aspirated
wall deposits). Fewer studies have been carried out in non- aerosol into the sampler. On the other hand, enough data have
metal industries. However, in the study of sewage composting now been accumulated to allow rough assumptions to be made
TABLE 1 Summary of Findings of Internal Wall Deposits as a Percentage of Total Analyzed Mass (Filter Plus Walls) in Field Samples for
Metals Using the 37-mm CFC Sampler
Work Environment/Activity
n Agent Median Wall Deposit Maximum Wall Deposit
(Reference)
Copper smelter (1) 18 Cu 21 % 55 %
Lead ore mill (5) 9Pb 19% 35%
Solder manufacture (6) 30 Pb 29 % 74 %
Battery production (7) 16 Pb 28 % 66 %
Battery recycling (8) 54 Pb 29 % 54 %
Welding (9) 10 Cr(VI) 5 % 55 %
Plating (9) 12 Cr(VI) 12 % 17 %
Paint spray (9) 29 Cr(VI) 7 % 12 %
Zn Foundry (7) 9Zn 53% 62%
Zn plating (7) 18 Zn 27 % 91 %
Cast iron foundry (7) 18 Fe 22 % 46 %
Grey iron foundry (7) 18 Fe 24 % 77 %
Bronze foundry (10) 6 Cu, Pb, Zn 19 %, 13 %, 15 % 45 %, 17 %, 21 %
Cuproberyllium alloying (7) 4 Cu, Be 31 %, 12 % 40 %, 39 %
Solder manufacturer (15) 50 Pb 45 % 77 %
Solder manufacturer (15) 47 Sn 56 % 93 %
D8358 − 21
TABLE 2 Summary of Findings of Internal Wall Deposits as a Percentage of Total Analyzed Mass (Filter Plus Walls) in Field Samples for
Metals Using the IOM Sampler
Work Environment/Activity
n Agent Median Wall Deposit Maximum Wall Deposit
(Reference)
Lead ore mill (5) 8Pb 19% 30%
Copper smelter (1) 17 Cu 16 % 38 %
Copper electrorefinery (2) 48 Cu 18 % 36 %
Battery production (11) 11 Pb 8 % 33 %
Welding (11) 18 Al 3 % 13 %
Cast iron foundry (7) 18 Fe 8 % 69 %
Grey iron foundry (7) 18 Fe 5 % 16 %
Bronze foundry (9) 6 Cu, Pb, Sn, Zn 0 %, 0 %, 0 %, 3 % 10 %, 3 %, 23 %, 6 %
regarding the effect of wall deposits on a large population of sampling and extraction. Originally the filter used consisted of
samples, either historically or for predictive purposes, includ-
quartz fiber media, but high background of some metals in
ing estimating the proportion of likely overexposures. These
these filters, together with the need for large quantities of
estimates become more precise where there is a body of data
hydrofluoric acid for complete dissolution of the filter, has led
involving filter-only and filter plus wall deposits from the
to replacement with a cellulose support pad and mixed cellu-
specific environment of interest.
lose ester (MCE) filter (28). After sampling, the cassette is
inverted and opened from the rear and the support pad
5.9 Samplers for the ISO 7708 respirable fraction of dust
have filters contained in holders downstream of (after) the removed, leaving the MCE filter in place. Acids (perchloric
size-separation device, typically a cyclone. These sample first, followed by nitric and hydrochloric, with hydrofluoric
holders, where not electrically conductive, have also been
where necessary) are pipetted into the cassette, which is then
shown to exhibit significant proportions of wall deposits. In a
sealed and placed in an ultrasonic bath for 10 minutes (being
studyoffieldsamples (19),upto32%oftotalcollectedquartz
upended after 5 minutes).
was found on the walls of 2-piece non-conductive styrene
NOTE 2—While this procedure purports to include wall deposits, and
cassettes and up to 55 % on the walls of 3-piece styrene
verylikelydoesso,theefficiencyofrecoveryofwalldepositshasnotbeen
non-conductive cassettes, which is similar to what was found
investigated systematically, for example by wiping the interiors of field
in laboratory studies (20).
sample cassettes after extraction.
6. Reagents and Equipment
7.2.3 A procedure that has often been used is to rinse the
6.1 For information on equipment and reagents to be used, interior of the sampler after removing the filter and adding the
see the specific applicable test method(s) (see 5.1 or other). washings to the solution used to extract or digest the filter.The
rinsate typically is acidic for metals analysis, aqueous for acid
7. Procedural Guidance
mists, basic for alkaline dusts or hexavalent chromium, or
7.1 Samples are typically collected in accordance with the
organicfororganicaerosols.However,rinsingprocedureshave
applicable test method (see 5.1 or other).
beentestedextensivelyforthe37-mmpolystyrenecassetteand
have been shown to result in recovery that is less than
7.2 After sample collection, the exterior of the sampler is
satisfactory (8, 29). Available evidence (see Table 2) suggests
carefully cleaned by wiping with an appropriate material to
that rinse recovery from other samplers by rinsing also is less
ensure the sample is not contaminated by material not consid-
ered part of the sample. Where the sample is considered to be thanfullyquantitative.Itislikelythattheprecisionofrecovery
all particles entering the aerosol sampler, the measurement
is better (lower) where there is fully quantitative removal of
procedure is intended to analyze all of the collected particles
material on internal sampler walls.
within the sampler.
7.2.4 Anotherprocedurethatisoftenusedentailswipingthe
7.2.1 For gravimetric analysis, when the filter is bonded to
interiorsurfacesofthesampler(containerorholder),digesting
a tared internal capsule (usually made from polyvinyl chloride
and analyzing the wipe separately or adding the wipe material
(PVC)), which includes all particles of interest, the capsule is
to the filter in the digestion step. This has been found to be
weighedinitsentiretybymeansofahigh-sensitivityanalytical
much more efficient than the rinsing procedure, even with a
balance (typically accurate to the nearest 0.001 mg) in an
single wipe (8, 29), although it is a manual technique poten-
environmentally-controlledarea.Themassofcollectedaerosol
tially subject to inter-personal or intra-personal variation.
is given by the difference in mass (in units of grams or
Wiping with a moistened wipe allows a combination of
miligrams) between the pre-weighed (prior to sampling) and
mechanical removal with wetting or solubilization.The choice
post-weighed (subsequent to sampling) internal capsule.
of wipe is important: it must be free of significant background
7.2.2 It is also possible to recover collected metalliferous
contaminationanditmustbecompatiblewiththedigestionand
aerosols through acid extraction/digestion within an aerosol
analytical procedure. Typically, the same material as would be
sampler, but the sampler must necessarily be watertight and
used for a surface wipe sample is to be preferred. These wipe
resistant to the extraction solution employed. A procedure for
materials are typically fully digestible in any acid mixture that
in-situ (that is, within-sampler) extraction in France (27) uses
a 3-piece polystyrene cassette as the container for both would be used to digest the filter. However, where the
D8358 − 21
procedurehasnotbeenvalidatedusinglaboratorysamples,the 164
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