ASTM D3608-95(2011)
(Test Method)Standard Test Method for Nitrogen Oxides (Combined) Content in the Atmosphere by the Griess-Saltzman Reaction
Standard Test Method for Nitrogen Oxides (Combined) Content in the Atmosphere by the Griess-Saltzman Reaction
SIGNIFICANCE AND USE
Both NO2 and NO play an important role in photochemical-smog-forming reactions. In sufficient concentrations NO2 is deleterious to health, agriculture, materials, and visibility.
In combustion processes, significant amounts of NO may be produced by combination of atmospheric nitrogen and oxygen; at ambient temperatures, NO can be converted to NO2 by oxygen and other atmospheric oxidants. Nitrogen dioxide also may be generated from processes involving nitric acid, nitrates, the use of explosives, and welding.
SCOPE
1.1 This test method covers the manual determination of the combined nitrogen dioxide (NO2) and nitric oxide (NO) content, total NOx; in the atmosphere in the range from 4 to 10 000 μg/m3 (0.002 to 5 ppm (v)).
1.2 The maximum sampling period is 60 min at a flow rate of 0.4 L/min.
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
1.4 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 and health practices and determine the applicability of regulatory limitations prior to use.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D3608 − 95 (Reapproved 2011)
Standard Test Method for
Nitrogen Oxides (Combined) Content in the Atmosphere by
the Griess-Saltzman Reaction
This standard is issued under the fixed designation D3608; 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 E128Test Method for Maximum Pore Diameter and Perme-
ability of Rigid Porous Filters for Laboratory Use
1.1 Thistestmethodcoversthemanualdeterminationofthe
combined nitrogen dioxide (NO ) and nitric oxide (NO)
3. Terminology
content, total NO ; in the atmosphere in the range from 4 to
x
3.1 Definitions—For definitions of terms used in this test
10000 µg/m (0.002 to 5 ppm (v)).
method, refer to Terminology D1356.
1.2 The maximum sampling period is 60 min at a flow rate
of 0.4 L/min.
4. Summary of Test Method
1.3 The values stated in SI units are to be regarded as
4.1 The NO is quantitatively (1) converted to NO by a
standard. The values given in parentheses are for information
chromicacidoxidizer.TheresultingNO ,plustheNO already
2 2
only.
present, are absorbed in an azo-dye-forming reagent (2).A
1.4 This standard does not purport to address all of the
red-violet color is produced within 15 min, the intensity of
safety concerns, if any, associated with its use. It is the
which is measured spectrophotometrically at 550 nm.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
5. Significance and Use
bility of regulatory limitations prior to use.
5.1 Both NO and NO play an important role in
photochemical-smog-forming reactions. In sufficient concen-
2. Referenced Documents
trationsNO isdeleterioustohealth,agriculture,materials,and
2.1 ASTM Standards:
visibility.
D1071Test Methods for Volumetric Measurement of Gas-
5.2 In combustion processes, significant amounts of NO
eous Fuel Samples
may be produced by combination of atmospheric nitrogen and
D1193Specification for Reagent Water
oxygen;atambienttemperatures,NOcanbeconvertedtoNO
D1356Terminology Relating to Sampling and Analysis of
by oxygen and other atmospheric oxidants. Nitrogen dioxide
Atmospheres
also may be generated from processes involving nitric acid,
D1357Practice for Planning the Sampling of the Ambient
nitrates, the use of explosives, and welding.
Atmosphere
D3195Practice for Rotameter Calibration
6. Interferences
D3609Practice for Calibration Techniques Using Perme-
6.1 Anysignificantinterferencesduetosulfurdioxide(SO )
ation Tubes
D3631Test Methods for Measuring Surface Atmospheric should be negated by the oxidation step. The addition of
acetone to the reagent retards color-fading by forming a
Pressure
E1Specification for ASTM Liquid-in-Glass Thermometers temporary addition product with SO . This will protect the
reagent from incidental exposure to SO and will permit
readingthecolorintensitywithin4to5h(insteadofthe45min
required without acetone) without appreciable losses.
This test method is under the jurisdiction of ASTM Committee D22 on Air
Quality and is the direct responsibility of Subcommittee D22.03 on Ambient
6.2 A five-fold ratio of ozone to NO will cause a small
Atmospheres and Source Emissions.
interference, the maximal effect occurring in 3 h. The reagent
Current edition approved Oct. 1, 2011. Published October 2011. Originally
approved in 1977. Last previous edition approved in 2005 as D3608–95 (2005). assumes a slightly orange tint.
DOI: 10.1520/D3608-95R11.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The boldface numbers in parentheses refer to the list of references appended to
the ASTM website. this test method.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3608 − 95 (2011)
acid mixture, rinse well with water, and redetermine the
maximum pore diameter.
7.3.3 Rinse the bubbler thoroughly with water and allow to
dry before using.
7.4 Mist Eliminator or Gas Drying Tube filled with acti-
vated charcoal or soda lime is used to prevent damage to the
flowmeter and pump.
7.5 Air-Metering Device—A calibrated glass variable-area
flowmeter, or dry gas meter coupled with a flow indicator
capableofaccuratelymeasuringaflowof0.4L/minissuitable.
7.6 Thermometer—ASTM Thermometer 33C, meeting the
requirements of Specification E1, will be suitable for most
applications of the method.
7.7 Manometer, accurate to 670 Pa (0.20 in. Hg].
7.8 Air Pump—A suction pump capable of drawing the
required sample flow for intervals of up to 60 min.
7.9 Spectrophotometer or Colorimeter—A laboratory in-
strument suitable for measuring the intensity of the red-violet
FIG. 1 Fritted Bubbler for Sampling Combined Nitrogen Oxides
color at 550 nm, with stoppered tubes or cuvettes. The
wavelength band-width is not critical for this determination.
7.10 Stopwatch or Timer.
6.3 The interferences from nitrous oxide and nitrogen
pentoxide, and other gases that might be found in polluted air
8. Reagents and Materials
are considered to be negligible.
8.1 Purity of Reagents—Reagent grade chemicals shall be
usedinalltests.Allreagentsshallconformtothespecifications
7. Apparatus
of the Committee on Analytical Reagents of the American
7.1 Sampling Probe—A glass or TFE-fluorocarbon (pre-
Chemical Society, where such specifications are available.
ferred) tube, 6 to 10 mm in diameter, provided with a
Other grades may be used, provided it is first ascertained that
downward-facing intake (funnel or tip). The dead volume of
the reagent is of sufficiently high purity to permit its use
thesystemshouldbekeptminimal,toavoidlossofNO onthe
x
without lessening the accuracy of the determination.
surfaces of the apparatus.
8.2 Purity of Water—Water shall be deionized water in
7.2 Oxidizer Tube—Soak 14 to 16-mesh firebrick or ⁄16-in.
accordance with Specification D1193 for Type I and II reagent
(1.5mm]molecularsievepelletsina17%aqueoussolutionof
water. Water must be nitrite-free.
chromium trioxide (CrO ) for 10 to 30 min.After draining the
8.3 Absorbing Reagent—Dissolve5gof anhydrous sulfa-
excess solution and drying in an oven at 105°C for 30 min, the
nilic acid (or 5.5 g of the monohydrate) in almost a litre of
solid oxidizer has a dull pink color. This color changes to rich
water containing 140 mLof glacial acetic acid. Gentle heating
yellow (active color) after 24-h equilibration with ambient air
is permissible to speed up the process. To the cooled mixture,
at 40 to 70% relative humidity, or after drawing ambient air
add 20 mL of the 0.1% stock solution of N-(1-naphthyl)-
through at a flow rate of 0.5 L/min for 1 h. A change in color
ethylenediaminedihydrochlorideand10-mLacetone.Diluteto
to a greenish brown indicates the exhaustion of oxidizing
1 L. The solution will be stable for several months if kept
ability, and progresses with a sharp boundary. Place about 3 g
well-stoppered in a brown bottle in the refrigerator. The
oftheoxidizerina30-mLmidgetimpinger,orfilla5-mmtube
absorbing reagent must be at room temperature before use.
to a height of 80 mm and plug each end with glass wool.
Avoidlengthycontactwithairduringbothpreparationanduse,
7.3 Absorber—Anall-glassbubblerwitha60-µmmaximum
since absorption of nitrogen dioxide will discolor the reagent.
pore diameter frit, commonly labeled “coarse,” similar to that
8.4 Chromic Acid Oxidant—Dissolve 17 g of chromium
illustrated in Fig. 1.
trioxide (CrO ) in 100 mL of water.
7.3.1 The porosity of the fritted bubbler, as well as the 3
sampling flow rate, affect absorption efficiency. An efficiency
8.5 N-(1-Naphthyl)-Ethylenediamine Dihydrochloride,
of over 95% may be expected with a flow rate of 0.4 L/min or
Stock Solution (0.1 %)—Dissolve 0.1 g of the reagent in 100
less and a maximum pore diameter of 60 µm. Frits having a
maximum pore diameter less than 60 µm will have a higher
efficiency, but will require an inconvenient pressure drop for
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
sampling.
listed by the American Chemical Society, see Analar Standards for Laboratory
7.3.2 Measure the porosity of an absorber in accordance
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
with Test Method E128. If the frit is clogged or visibly
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
discolored, carefully clean with concentrated chromic-sulfuric MD.
D3608 − 95 (2011)
mL of water. The solution will be stable for several months if from 0.2 to 15 L/min. The flow rate of the sampling system
kept well-stoppered in a brown bottle in the refrigerator. determines the lower limit for the flow rate of diluent gases.
(Alternatively,weighedsmallamountsofthesolidreagentmay The flow rates of the nitrogen and the diluent air must be
be stored.) measured to an accuracy of 1 to 2%. With a tube permeating
NO at a rate of 0.1 µL/min (0.19 µg/min), the range of
8.6 Sodium Nitrite (NaNO ), Standard Solution (0.0246
concentration of NO will be between 20 to 1000 µg/m (0.01
g/L)—One mL of this working solution of NaNO produces a
to 0.50 ppm (v)), a generally satisfactory range for ambient air
colorequivalenttothatof20µgofNO in1Lofairat101kPa
conditions. When higher concentrations are desired, calibrate
(29.92 in. Hg] and 25°C (see 10.2.2). Prepare fresh just before
using longer permeation tubes.
use by diluting from a stock solution containing 2.460 g/L of
10.2.1.4 Procedure for Preparing Simulated Calibration
NaNO (calculated as 100%). It is desirable to assay the solid
Curves—A multitude of curves may be prepared by selecting
reagent (3). The stock solution is stable for 90 days at room
differentcombinationsofsamplingrateandsamplingtime.The
temperatures, and for a year in a brown bottle under refrigera-
following description represents a typical procedure for ambi-
tion.
ent air sampling of short duration. The system is designed to
8.7 NO Permeation Device—See Practice D3609.
provideanaccuratemeasureofNO inthe40to10 000µg/m
(0.02 to 5 ppm (v)) range. It can be modified to meet special
9. Sampling
needs.
9.1 Sampling procedures are described in Section 11. Dif-
10.2.1.5 The dynamic range of the colorimetric procedure
ferent combinations of sampling rates and time may be chosen
fixes the total volume of the sample at 24 L, then to obtain
to meet special needs, but sample volumes and air flow rates
linearity between the absorbance of the solution and the
must be adjusted so that linearity is maintained between
concentration of NO in parts per million by volume, select a
absorbance and concentration over the dynamic range.
constant sampling time. This fixing of sampling time is also
9.2 See Practices D1357 for sampling guidelines. desirable from a practical standpoint. In this case, select a
sampling time of 60 min. Then, to obtain a 24-L sample
10. Calibration and Standardization
requiresaflowrateof0.4L/min.Calculatetheconcentrationof
standard NO in air as follows:
10.1 Sampling Equipment—If a flowmeter is used to mea-
sure sample air, calibrate it prior to use using Practice D3195.
P 1000
~ !
C 5 (1)
If a gas meter is used, calibrate it prior to use in accordance
R1r
with Test Method D1071.
where:
10.2 Analysis: 3
C = concentration of NO µg/m ,
10.2.1 Recommended Procedure:
P = permeation rate, µg/min,
10.2.1.1 Calibrated permeation tubes that contain liquefied
R = flow rate of diluent air, L/min,
NO can be used to prepare standard concentrations of NO in
2 2 r = flow rate of diluent nitrogen, L/min, and
air (4). See Practice D3609 for details. Analyses of these
1000 = conversion factor to convert L to m .
known concentrations give calibration curves that simulate all
10.2.1.6 A plot of the concentration of NO in µg/m
the operational conditions performed during the sampling and
(x-axis) against absorbance of the final solution (y-axis) will
chemical procedures. This calibration curve includes the im-
yield a straight line, the inverse or the slope of which is the
portant correction for collection efficiency at various concen-
factor for conversion of absorbance to µg/m . This factor
trations of NO .
includes the correction for collection efficiency.Any deviation
10.2.1.2 Prepare or obtain a TFE-fluorocarbon permeation
from linearity at the lower concentration range indicates a
tube that emits NO at a rate of 0.1 to 0.2 µg/min (0.05 to 0.1µ
change in collection efficiency of the sampling system.
L/min at standard conditions of 25°C and 101.3 kPa (29.92 in.
Actually, the standard concentration of 20 µg/m is slightly
Hg].Calibratepermeationtubesunderastreamofdrynitrogen,
below the dynamic range of the method. If this is the range of
using Practice D3609.
interest,thetotalvolumeofaircollectedshouldbeincreasedto
10.2.1.3 To prepare standard concentrations of NO as-
obtain sufficient color within the dynamic range of the colori-
semble the apparatus, as shown in Practice D3609, consisting
metric procedure. Also, once the calibration factor has been
of a water-cooled condenser; constant-temperature water bath
established under simulated conditions, the conditions can be
maintainedat20°C;cylinderscontainingpuredrynitrogenand
modified so that the concentration of NO is a simple multiple
pure dry air, with appropriate pressure regulators; needle
of the absorbance of the colored solution.
valves and flowmeters for the nitrogen and dry air diluent gas
10.2.2 Alternate Procedure:
streams. Bring the diluent gases to temperature by passage
10.2.2.1 Standardization is based upon the empirical obser-
through a 2-m long copper coil immersed in the water bath.
vation (5) that 0.82 mol of NaNO produces the same color as
Insert a calibrated permeation tube into the central tube of the 2
1 mol of NO . One mL of the working standard contains 24.6
condenser maintained at 20°C by circulating water from the
µg of NaNO . Since the molecular weight of NaNO is 69.1,
constant-temperature bath and pass a stream of nitrogen over 2 2
this is equivalent to: (24.6/69.1)×(46.0⁄0.82)=20 µg of NO .
thetubeatafixedrateofapproximately50mL/min.Dilutethis
gasstreamtothedesiredconcentrationbyvaryingtheflowrate 10.2.2.2 For convenience, standard conditions are taken as
of the “clean dry air.” This flow rate can normally
...
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