1、Designation: D 5011 92 (Reapproved 2003)Standard Practices forCalibration of Ozone Monitors Using Transfer Standards1This standard is issued under the fixed designation D 5011; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 These practices describe means for calibrating ambient,workplace or indoor ozone monitors, using transfer stand
3、ards.1.2 These practices describe five types of transfer standards:(A) Analytical instruments(B) Boric acid potassium iodide (BAKI) manual analyticalprocedure(C) Gas phase titration with excess nitric oxide(D) Gas phase titration with excess ozone(E) Ozone generator device.1.3 These practices descri
4、be procedures to establish theauthority of transfer standards: qualification, certification, andperiodic recertification.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-p
5、riate safety and health practices and determine the applica-bility of regulatory limitations prior to use. See Section 8 forspecific precautionary statements.2. Referenced Documents2.1 ASTM Standards:2D 1071 Test Methods for Volumetric Measurement of Gas-eous Fuel SamplesD 1193 Specification for Rea
6、gent WaterD 1356 Terminology Relating to Sampling and Analysis ofAtmospheresD 3195 Practice for Rotameter CalibrationD 3249 Practice for General Ambient Air Analyzer Proce-duresD 3631 Test Methods for Measuring Surface AtmosphericPressureD5110 Practice for Calibration of Ozone Monitors andCertificat
7、ion of Ozone Transfer Standards Using Ultravio-let PhotometryE 591 Practice for Safety and Health Requirements Relatingto Occupational Exposure to Ozone2.2 Other Documents:40 CFR Part 50, Environmental Protection Agency Regula-tions on Ambient Air Monitoring Reference Methods33. Terminology3.1 For d
8、efinitions of terms used in this standard, seeTerminology D 1356.3.2 Definitions of Terms Specific to This Standard:3.2.1 primary standarda standard directly defined andestablished by some authority, against which all secondarystandards are compared.3.2.2 secondary standarda standard used as a means
9、 ofcomparison, but checked against a primary standard.3.2.3 standardan accepted reference sample or deviceused for establishing measurement of a physical quantity.3.2.4 transfer standarda type of secondary standard. It isa transportable device or apparatus, which, together withoperational procedures
10、, is capable of reproducing pollutantconcentration or producing acceptable assays of pollutantconcentrations.3.2.5 zero airpurified air that does not contain ozone anddoes not contain any other component that may interfere withthe measurement. See 7.1.3.3 Symbols:b = Spectrophotometer cell path leng
11、th, cm. SeeAnnex A2.davg= Average of discrete single point compari-sons. See Annex A1.di= Single point comparison. See Annex A1.FD= Diluent air flow, mL/min.FD8 = New diluent air flow, mL/min.FNO= NO flow, mL/min.FO= Flow through the O3generator, mL/min.1These practices are under the jurisdiction of
12、 ASTM Committee D22 on AirQuality and are the direct responsibility of Subcommittee D22.03 on AmbientAtmospheres and Source Emissions.Current edition approved April 10, 2003. Published June 2003. Originallyapproved in 1989. Last previous edition approved in 1997 as D 5011 92 (1997)e1.2For referenced
13、 ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from the Superintendent of Documents, U.S. Government PrintingOff
14、ice, Washington, DC 20402.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.FR= Flowrate corrected to reference conditions(25C and 101.3 kPa), mL/min. See AnnexA2.FS= Flowrate at sampling conditions, mL/min.See Annex A2.FT= The total f
15、low required at the output mani-fold (monitors demand plus 10 to 50 %excess), mL/min.I = The intensity of light which passes throughthe photometer absorption cell and is sensedby the detector when the cell contains an O3sample. See Annex A4.I2i= Concentration of each I2standard, mol I2/L.See Annex A
16、2.Iavg= Average intercept. See Annex A1.Ii= Individual intercepts. See Annex A1.IO= The intensity of light which passes throughthe photometer absorption cell and is sensedby the detector when the cell contains zeroair. See Annex A4.mavg= Average slope. See Annex A1.mi= Individual slopes. See Annex A
17、1.mol I2=I2released, mols. See Annex A2.NKIO3= Normality of KIO3, equivalent/L. SeeAnnexA2.NO = Diluted NO concentration, ppm. See AnnexA4.NOORIG= Original NO concentration, ppm. See AnnexA3.NOOUT= Highest NO concentration required at theoutput manifold, ppm. It is approximatelyequal to 90 % of the
18、upper range limit of theO3concentration to be determined. See An-nex A3.NORC= NO concentration (approximate) in the reac-tion chamber, ppm. See Annex A3.NOREM= NO concentration remaining after addition ofO3, ppm. See Annex A3.NOSTD= Concentration of the undiluted NO standard,ppm.n = Number of compar
19、isons. See Eq 4O3CERT= Certified O3concentration, ppm.O3CERT8= Diluted certified O3concentration, ppm.O3GEN=O3concentration produced by the O3genera-tor, ppm. See Annex A4.O3OUT= Indicated O3concentration, ppm. See AnnexA2.O3OUT8= Diluted O3concentration, ppm.O3RC=O3concentration (approximate) at th
20、e outputmanifold, ppm.PH2O= Vapor pressure of H2OatTS, kPa, wetvolume standard. (For a dry standard,PH2O= 0.) (See Test Method D 4230 fortables of saturation vapor pressure of water.)See Annex A2.PR= Dynamic specification, determined empiri-cally, to ensure complete reaction of O3orNO, ppm/min.PS= B
21、arometric pressure at sampling conditions,kPa. See Annex A2.Sc= Slope of KI calibration curve, mL/mol/cm.See Annex A2.sd= Standard deviation of single point compari-sons. See Annex A1.si= Relative standard deviation of the six inter-cepts. See Annex A1.sm= Relative standard deviation of the six slop
22、es.See Annex A1.tR= Residence time in reaction chamber, min.ts= Sampling time, min. See Annex A2.TS= Temperature at sampling conditions, C. SeeAnnex A2URL = Upper range limit of O3or NO monitor, ppm.Vi= Volume of I2solution, mL. See Annex A2VO3= Volume of O3absorbed, L. See Annex A2.VR= Volume of ai
23、r sampled, corrected to 25Cand 101.3 kPa (1 atm), mL. See Annex A2.VRC= Volume of the reaction chamber, mL.yi=O3concentration indicated by the transferstandard, ppm. See 10.6.2.Z = Recorder response with zero air, % scale.4. Summary of Practices4.1 These practices describe the procedures necessary t
24、oestablish the authority of ozone transfer standards: qualifica-tion, certification, and periodic recertification. Qualificationconsists of demonstrating that a candidate transfer standard issufficiently stable (repeatable) to be useful as a transferstandard. Repeatability is necessary over a range
25、of variables(such as temperature, line voltage, barometric pressure, elapsedtime, operator adjustments, relocation, etc.), any of which maybe encountered during use of the transfer standard. Tests andpossible compensation techniques for several such commonvariables are described. Detailed certificat
26、ion procedures areprovided, and the quantitative specifications necessary tomaintain continuous certification of the transfer standard arealso provided.4.2 Method AA dedicated ozone monitor is tested asdescribed in 4.1 to demonstrate its authority as a transferstandard.4.3 Method BThis method (1)4is
27、 based on the reactionbetween ozone (O3) and potassium iodide (KI) to releaseiodine (I2) in accordance with the following stoichiometricequation (2):O31 2I21 2H15 I21 H2O 1 O2(1)The stoichiometry is such that the amount of I2released isequal to the amount of O3absorbed. Ozone is absorbed in a 0.1N b
28、oric acid solution containing 1 % KI, and the I2releasedreacts with excess iodide ion (I) to form triiodide ion (I3),which is measured spectrophotometrically at a wavelength of352 nm. The output of a stable O3generator is assayed in thismanner, and the O3generator is immediately used to calibratethe
29、 O3monitor.4.4 Method CThis procedure is based on the rapid gasphase reaction between nitric oxide (NO) and O3, as describedby the following equation (3):4The boldface numbers in parentheses refer to the references at the end of thesepractices.D 5011 92 (2003)2NO 1 O35 NO 1 O2(2)When O3is added to e
30、xcess NO in a dynamic system, thedecrease in NO response is equivalent to the concentration ofO3added. The NO is obtained from a standard NO cylinder,and the O3is produced by a stable O3generator. A chemilu-minescence NO analyzer is used to measure the change in NOconcentration. The concentration of
31、 O3added may be varied toobtain calibration concentrations over the range desired. Thedynamic system is designed to produce locally high concen-trations of NO and O3in the reaction chamber, with subsequentdilution, to effect complete O3reaction with relatively smallchamber volumes.4.5 Method DThis p
32、rocedure is based on the rapid gasphase reaction between O3and nitric oxide (NO) as describedby the following equation (3):NO 1 O35 NO21 O2(3)When NO is added to excess O3in a dynamic system, thedecrease in O3response observed on an uncalibrated O3monitor is equivalent to the concentration of NO add
33、ed. Bymeasuring this decrease in response and the initial response,the O3concentration can be determined. Additional O3con-centrations are generated by dilution. The gas phase titration(GPT) system is used under predetermined flow conditions toinsure that the reaction of NO is complete and that furt
34、herreaction of the resultant nitrogen dioxide (NO2) with residualO3is negligible.4.6 Method EA dedicated ozone generator is tested asdescribed in 4.1 to demonstrate its authority as a transferstandard.5. Significance and Use5.1 The reactivity and instability of O3precludes the storageof O3concentrat
35、ion standards for any practical length of time,and precludes direct certification of O3concentrations asSRMs. Moreover, there is no available SRM that can bereadily and directly adapted to the generation of O3standardsanalogous to permeation devices and standard gas cylinders forsulfur dioxide and n
36、itrogen oxides. Dynamic generation of O3concentrations is relatively easy with a source of ultraviolet(UV) radiation. However, accurately certifying an O3concen-tration as a primary standard requires assay of the concentra-tion by a comprehensively specified analytical procedure,which must be perfor
37、med every time a standard is needed.5.2 The primary UV standard photometers, which are usu-ally used at a fixed location under controlled conditions, areused to certify transfer standards that are then transported to thefield sites where the ambient ozone monitors are being used.See Practice D5110.5
38、.3 The advantages of this procedure are:5.3.1 All O3monitors in a given network or region may betraced to a single primary standard.5.3.2 The primary standard is used at only one location,under controlled conditions.5.3.3 Transfer standards are more rugged and more easilyportable than primary standa
39、rds.5.3.4 Transfer standards may be used to intercompare vari-ous primary standards.6. Apparatus6.1 Apparatus Common to Methods A Through E:6.1.1 UV Photometric calibration system, as shown in Fig.1, consisting of the following:6.1.1.1 Primary Ozone Standarda UV photometer, con-sisting of a low-pres
40、sure mercury discharge lamp, collimationoptics (optional), an absorption cell, a detector, and signal-processing electronics. It shall be capable of measuring theFIG. 1 Schematic Diagram of a Typical UV Photometric Calibration SystemD 5011 92 (2003)3transmittance, I/I0, at a wavelength of 253.7 nm w
41、ith sufficientprecision that the standard deviation of the concentrationmeasurements does not exceed the greater of 0.005 ppm or 3 %of the concentration. It shall incorporate means to assure thatno O3is generated in the cell by the UV lamp. This is generallyaccomplished by filtering out the 184.9 nm
42、 Hg line with a highsilica filter. In addition, at least 99.5 % of the radiation sensedby the detector shall be 253.7 nm. This is usually accomplishedby using a solar blind photodiode tube. The length of the lightpath through the absorption cell shall be known with anaccuracy within at least 99.5 %.
43、 In addition the cell andassociated plumbing shall be designed to minimize loss of O3from contact with surfaces (4). See Practice D5110.6.1.1.2 Air Flow Controllercapable of regulating air flowsas necessary to meet the output stability and photometerprecision requirements.6.1.1.3 Flowmeterscalibrate
44、d in accordance with PracticeD 3195.6.1.1.4 Ozone Generatorcapable of generating stable lev-els of O3over the required concentration range. It shall bestable over short periods to allow for stability of the monitor ortransfer standard connected to the output manifold. Conven-tional UV-photolytic typ
45、e generators may be adequate but shallhave line voltage and temperature regulation.6.1.1.5 Output Manifoldconstructed of glass, TFE-fluorocarbon, or other relatively inert material. It shall be ofsufficient diameter to cause a negligible pressure drop at thephotometer connection and other output por
46、ts. The outputmanifold serves the function of providing an interface betweenthe calibration system and other devices and systems thatutilize the output O3concentrations. It shall have one or moreports for connection of the external instruments or systems, andshall be such that all ports provide the
47、same O3concentrations.The vent, which exhausts excess gas flow from the system andinsures that the manifold outlet ports are maintained at atmo-spheric pressure for all flowrates, shall be large enough toavoid appreciable pressure drop, and shall be located down-stream of the output ports to insure
48、that no ambient air entersthe manifold due to eddy currents, back diffusion, etc.6.1.1.6 Temperature Indicatoraccurate to 61C. This in-dicator is needed to measure the temperature of the gas in thephotometric cell in order to calculate a temperature correction.In most photometers, particularly those
49、 whose cell is enclosedinside a case or housing with other electrical or electroniccomponents, the cell operates at a temperature somewhatabove ambient room temperature. Therefore, it is important tomeasure the temperature of the gas inside the cell, and notroom temperature. A small thermocouple or thermistor, con-nected to an external readout device, may be attached to thecell wall or inserted through the cell wall to measure internaltemperature.6.1.1.7 Barometer or Pressure Indicatoraccurate to 6250Pa (2 Torr). The barometer or p
