ASTM D2914-15(2022)
(Test Method)Standard Test Methods for Sulfur Dioxide Content of the Atmosphere (West-Gaeke Method)
Standard Test Methods for Sulfur Dioxide Content of the Atmosphere (West-Gaeke Method)
SIGNIFICANCE AND USE
5.1 Sulfur dioxide is a major air pollutant, commonly formed by the combustion of sulfur-bearing fuels. The Environmental Protection Agency (EPA) has set primary and secondary air quality standards (7) that are designed to protect the public health and welfare.
5.2 The Occupational Safety and Health Administration (OSHA) has promulgated exposure limits for sulfur dioxide in workplace atmospheres (8).
5.3 These methods have been found satisfactory for measuring sulfur dioxide in ambient and workplace atmospheres over the ranges pertinent in 5.1 and 5.2.
5.4 Method A has been designed to correspond to the EPA-Designated Reference Method (7) for the determination of sulfur dioxide.
SCOPE
1.1 These test methods cover the bubbler collection and colorimetric determination of sulfur dioxide (SO2) in the ambient or workplace atmosphere.
1.2 These test methods are applicable for determining SO2 over the range from approximately 25 μg/m3 (0.01 ppm(v)) to 1000 μg/m3 (0.4 ppm(v)), corresponding to a solution concentration of 0.03 μg SO2/mL to 1.3 μg SO2/mL. Beer's law is followed through the working analytical range from 0.02 μg SO2/mL to 1.4 μg SO2/mL.
1.3 The lower limit of detection is 0.075 μg SO2/mL (1),2 representing an air concentration of 25 μg SO2/m3 (0.01 ppm(v)) in a 30-min sample, or 13 μg SO2/m3 (0.005 ppm(v)) in a 24-h sample.
1.4 These test methods incorporate sampling for periods between 30 min and 24 h.
1.5 These test methods describe the determination of the collected (impinged) samples. A Method A and a Method B are described.
1.6 Method A is preferred over Method B, as it gives the higher sensitivity, but it has a higher blank. Manual Method B is pH-dependent, but is more suitable with spectrometers having a spectral band width greater than 20 nm.
Note 1: These test methods are applicable at concentrations below 25 μg/m3 by sampling larger volumes of air if the absorption efficiency of the particular system is first determined, as described in Annex A4.
Note 2: Concentrations higher than 1000 μg/m3 can be determined by using smaller gas volumes, larger collection volumes, or by suitable dilution of the collected sample with absorbing solution prior to analysis.
1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.8 Warning—Mercury has been designated by many regulatory agencies as a hazardous material that can cause serious medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Caution should be taken when handling mercury and mercury containing products. See the applicable product Safety Data Sheet (SDS) for additional information. Users should be aware that selling mercury and/or mercury containing products into your state or country may be prohibited by law.
1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see 8.3.1, Section 9, and A3.1.3.
1.10 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.
General Information
Relations
Standards Content (Sample)
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: D2914 − 15 (Reapproved 2022)
Standard Test Methods for
Sulfur Dioxide Content of the Atmosphere (West-Gaeke
Method)
This standard is issued under the fixed designation D2914; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 1.8 Warning—Mercury has been designated by many regu-
latory agencies as a hazardous material that can cause serious
1.1 These test methods cover the bubbler collection and
medical issues. Mercury, or its vapor, has been demonstrated to
colorimetric determination of sulfur dioxide (SO)inthe
be hazardous to health and corrosive to materials. Caution
ambient or workplace atmosphere.
should be taken when handling mercury and mercury contain-
1.2 These test methods are applicable for determining SO
ing products. See the applicable product Safety Data Sheet
over the range from approximately 25 µg/m (0.01 ppm(v)) to
(SDS) for additional information. Users should be aware that
1000 µg/m (0.4 ppm(v)), corresponding to a solution concen-
selling mercury and/or mercury containing products into your
tration of 0.03 µgSO /mL to 1.3 µgSO /mL. Beer’s law is
2 2
state or country may be prohibited by law.
followed through the working analytical range from 0.02 µg
1.9 This standard does not purport to address all of the
SO /mL to 1.4 µgSO /mL.
2 2
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
1.3 The lower limit of detection is 0.075 µgSO /mL (1),
representing an air concentration of 25 µgSO /m priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
(0.01ppm(v)) in a 30-min sample, or 13 µgSO /m (0.005
ppm(v)) in a 24-h sample. Forspecificprecautionarystatements,see8.3.1,Section9,and
A3.1.3.
1.4 These test methods incorporate sampling for periods
1.10 This international standard was developed in accor-
between 30 min and 24 h.
dance with internationally recognized principles on standard-
1.5 These test methods describe the determination of the
ization established in the Decision on Principles for the
collected(impinged)samples.AMethodAandaMethodBare
Development of International Standards, Guides and Recom-
described.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.6 Method A is preferred over Method B, as it gives the
higher sensitivity, but it has a higher blank. Manual Method B
2. Referenced Documents
is pH-dependent, but is more suitable with spectrometers
2.1 ASTM Standards:
having a spectral band width greater than 20 nm.
D1193Specification for Reagent Water
NOTE 1—These test methods are applicable at concentrations below
D1356Terminology Relating to Sampling and Analysis of
25 µg/m by sampling larger volumes of air if the absorption efficiency of
Atmospheres
the particular system is first determined, as described in Annex A4.
NOTE 2—Concentrations higher than 1000 µg/m can be determined by D1357Practice for Planning the Sampling of the Ambient
using smaller gas volumes, larger collection volumes, or by suitable
Atmosphere
dilution of the collected sample with absorbing solution prior to analysis.
D1914PracticeforConversionUnitsandFactorsRelatingto
1.7 The values stated in SI units are to be regarded as
Sampling and Analysis of Atmospheres
standard. No other units of measurement are included in this
D3195Practice for Rotameter Calibration
standard.
D3609Practice for Calibration Techniques Using Perme-
ation Tubes
D3631Test Methods for Measuring Surface Atmospheric
These test methods are under the jurisdiction ofASTM Committee D22 on Air
Quality and are the direct responsibility of Subcommittee D22.03 on Ambient
Pressure
Atmospheres and Source Emissions.
Current edition approved March 1, 2022. Published April 2022. Originally
approved in 1970. Last previous edition approved in 2015 as D2914–15. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
DOI:10.1520/D2914-15R22. 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
D2914 − 15 (2022)
E1Specification for ASTM Liquid-in-Glass Thermometers heavy metals by EDTA and phosphoric acid (4, 5). At least
E275PracticeforDescribingandMeasuringPerformanceof 60 µg of Fe(III), 10 µg of Mn(II), and 10 µg of Cr(III), 10 µg
Ultraviolet and Visible Spectrophotometers ofCu(II)and22 µgofV(V)in10mLofabsorbingreagentcan
E2251Specification for Liquid-in-Glass ASTM Thermom- be tolerated in the procedure. No significant interference was
eters with Low-Hazard Precision Liquids found with 2.3 µgofNH (9).
2.2 Other Standards:
40 CFR Part 58 Probe and Monitoring Path Siting Criteria 7. Apparatus
from Ambient Air Quality Monitoring, Appendix E
7.1 For Sampling:
7.1.1 Absorber, Short–Term Sampling—An all-glass midget
3. Terminology
impinger having a solution capacity of 30 mL and a stem
3.1 For definitions of terms used in this method, refer to
clearance of 4 6 1 mm from the bottom of the vessel is used
Terminology D1356.
for sampling periods of 30 min and 1 h (or any period
considerably less than 24 h).
4. Summary of Test Methods
7.1.2 Absorber, 24-h Sampling—A glass or polypropylene
4.1 Sulfur dioxide (SO ) is absorbed by aspirating a mea-
tube 32 mm in diameter and 164 mm long with a polypropyl-
sured air sample through a tetrachloromercurate (TCM)
enetwo-portcap(rubberstoppersareunacceptablebecausethe
solution, resulting in the formation of a dichlorosulfonatomer-
absorbing reagent can react with the stopper to yield errone-
curate complex (2, 3). Ethylenediaminetetraacetic acid diso-
ously high SO concentrations, and cause high and variable
dium salt (EDTA) is added to this solution to complex heavy
blank values). Insert a glass impinger stem, 6 mm inside
metals that interfere with this method (4).
diameter and 158 mm long, into one port of the absorber cap.
Dichlorosulfonatomercurate, once formed, is stable to strong
Taper the tip of the stem to a small diameter orifice (0.4 6
oxidants(forexample,ozoneandoxidesofnitrogen) (2).After
0.1mm)suchthataNo.79jeweler’sdrillbitwillpassthrough
the absorption is completed, any ozone in the solution is
the opening but a No. 78 drill bit will not. Clearance from the
allowed to decay (5). The liquid is treated first with a solution
bottomoftheabsorbertothetipofthestemshallbe6 62mm.
of sulfamic acid to destroy the nitrite anion formed from the
Perform the orifice test before use to verify the orifice size.
absorption of oxides of nitrogen present in the atmosphere (6).
Permanentlymarkthe50mLvolumelevelontheabsorber.See
It is treated next with solutions of formaldehyde and specially
Fig. 1.
purified acid-bleached pararosaniline containing phosphoric
7.1.3 Air Sample Probe—A sample probe meeting the re-
acid(H PO )tocontrolpH.Pararosaniline,formaldehyde,and
3 4
quirements of Section 7 of 40 CFR Part 58, Appendix E,
the bisulfite anion react to form the intensely colored pararo-
(TFE-fluorocarbon, polypropylene, or glass with a residence
saniline methyl sulfonic acid which behaves as a two-color pH
time less than 20 sec), used to transport ambient air to the
indicator (2). The pH of the final solution is adjusted to the
sampling train location. Design or orient the end of the probe
desired value by the addition of prescribed amounts of 3 N
to preclude the sampling of precipitation, large particles, etc.
H PO to the pararosaniline reagent (5).
3 4
7.1.4 Moisture Trap—Glass or polypropylene trap as shown
5. Significance and Use
in Fig. 1, placed between the absorber tube and flow control
device to prevent entrained liquid from reaching the flow
5.1 Sulfur dioxide is a major air pollutant, commonly
control device. Pack the tube with coconut charcoal and glass
formed by the combustion of sulfur-bearing fuels. The Envi-
wool or with indicating silica gel. Charcoal is preferred when
ronmental Protection Agency (EPA) has set primary and
collecting long-term samples (1 h or more) if flow changes are
secondary air quality standards (7) that are designed to protect
routinely encountered.
the public health and welfare.
7.1.5 Cap Seals—Seal the absorber and moisture trap caps
5.2 The Occupational Safety and Health Administration
securely to prevent leaks during use, by using heat-shrink
(OSHA) has promulgated exposure limits for sulfur dioxide in
material to prevent the caps coming loose during sampling,
workplace atmospheres (8).
shipment, or storage.
5.3 These methods have been found satisfactory for mea-
7.1.6 Filter,membrane,of0.8to2.0 µmporosity,withfilter
suring sulfur dioxide in ambient and workplace atmospheres
holder, to protect the flow controller from particles during
over the ranges pertinent in 5.1 and 5.2.
long-term sampling. This item is optional for short-term
5.4 Method A has been designed to correspond to the sampling.
EPA-Designated Reference Method (7) for the determination
7.1.7 Pump,equippedwithvacuumgauge,capableofmain-
of sulfur dioxide.
taining a vacuum greater than 70 kPa (0.7 atm) at the specified
flow rate across the flow control device.
6. Interferences
7.1.8 Flow Control and Measurement Devices:
6.1 The interferences of oxides of nitrogen are eliminated
7.1.8.1 Flow Control Device—A calibrated rotameter and
by sulfamic acid (5, 6), of ozone by time delay (5), and of
needle valve combination capable of maintaining and measur-
ing air flow to within 62 percent is suitable for short-term
sampling but shall not be used for long-term sampling. A
Available from U.S. Government Publishing Office (GPO), 732 N. Capitol St.,
NW, Washington, DC 20401, http://www.gpo.gov. critical orifice can be used for regulating flow rate for both
D2914 − 15 (2022)
FIG. 1 Sampling System
long-term and short-term sampling. Use a 22-gauge hypoder- of the 15 6 10°C range to minimize losses during this period.
mic needle 25 mm long as a critical orifice (10) to yield a flow Thermoelectric coolers specifically designed for this tempera-
rate of approximately 1 L/min for a 30-min sampling period. ture control are available commercially and normally operate
When sampling for 1 h, use a 23-gauge hypodermic needle in the range of 5 to 15°C. Small refrigerators can be modified
16mm in length to provide a flow rate of approximately to provide the required temperature control; however, insulate
0.5L⁄min. Provide a flow control for a 24-h sample by a the inlet lines from the lower temperatures to prevent conden-
27-gauge hypodermic needle critical orifice that is 9.5 mm in sationwhensamplingunderhumidconditions.Asmallheating
lengthsothattheflowrateisintherangeof0.18to0.22L/min. pad may be necessary when sampling at low temperatures
7.1.8.2 Flow Measurement Device—Calibrated as specified (<7°C) to prevent the absorbing solution from freezing (11).
in 11.1.1, and used to measure sample flow rate at the
7.1.12 Sampling Train Container—A light-proof box to
monitoring site.
shield the absorbing solution from light during and after
7.1.9 Thermometer—ASTMThermometer33C,meetingthe
sampling.
requirementsofSpecificationE1willmeettherequirementsof
7.1.13 Timer—To initiate and to stop sampling for the 24-h
most applications in this method. A comparable precision
sampling period. This is not a required piece of equipment;
low-hazard liquid thermometer, ASTM Thermometer S33C,
however, without the timer it will be necessary to manually
meeting the requirements of Specification E2251, may also be
startandstopthesampling.Anelapsedtimemetermayalsobe
used.
used to determine the sampling period.
7.1.10 Barograph or Barometer, capable of measuring at-
7.1.14 The arrangement of the component parts for sam-
mospheric pressure to 60.5 kPa (5 torr). (See Test Methods
pling is shown in Fig. 1.
D3631.)
7.2 Shipping:
7.1.11 Temperature Control Device—To maintain the tem-
perature of the absorbing solution during sampling at 15 6 7.2.1 Shipping Container—To maintain a temperature of 5
10°C.Maintainthetemperatureofthecollectedsampleat5 6 6 5°C while transporting the sample from the collection site
5°C,assoonaspossiblefollowingsamplinganduntilanalysis. totheanalyticallaboratory.Icecoolersorrefrigeratedshipping
Where an extended period of time may elapse before the containers have been found to be satisfactory. The use of
collected sample can be moved to the lower storage eutectic cold packs instead of ice will give a more stable
temperature, use a collection temperature near the lower limit temperature control.
D2914 − 15 (2022)
7.3 Analysis: and 6.0 g KCl in distilled water and dilute to volume with
7.3.1 Spectrophotometer or Colorimeter—The instrument distilled water in a 1000–mL volumetric flask. The pH of this
shall be suitable for measurement of color at 548 nm for reagentshouldbebetween3.0and5.0 (5).CheckthepHofthe
MethodAor575nmforMethodB.ForMethodA,aneffective absorbingsolutionbyusingpHindicatingpaperorapHmeter.
spectralbandwidthoflessthan15nmisrequiredsincereagent If the pH of the solution is not between 3.0 and 5.0, dispose of
blank problems may otherwise result. Verify the wavelength the solution in accordance with the disposal technique de-
calibration of the spectrophotometer in accordance with Prac- scribed in AnnexA3.The absorbing reagent is normally stable
tice E275 upon initial receipt of the instrument and after each for 6 months. If a precipitate forms, dispose of the reagent in
160 h or normal use or every 6 months, whichever occurs first, accordancewithAnnexA3.(Warning—Mercuricchlorideand
using a standard wavelength filter traceable to the National TCM are very poisonous, particularly when concentrated.
Institute of Standards and Technology. Avoid contact with skin and especially, with eyes. Avoid
7.3.2 Spectrophotometer Cells—A set of 1-cm path length generating or breathing dust. Keep away from food. Wash
cells suitable for use in the visible region. If the cells are hands after use. Do not
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