1、Designation: D 3824 95 (Reapproved 2005)Standard Test Methods forContinuous Measurement of Oxides of Nitrogen in theAmbient or Workplace Atmosphere by theChemiluminescent Method1This standard is issued under the fixed designation D 3824; the number immediately following the designation indicates the
2、 year oforiginal adoption or, in the case of revision, the year 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 test methods cover procedures for the contin
3、uousdetermination of total nitrogen dioxide (NO2) and nitric oxide(NO) as NOx, or nitric oxide (NO) alone or nitrogen dioxide(NO2) alone, in the ranges shown in the following table:Range of ConcentrationGas Ambient Atmosphere Workplace Atmosphereg/m3(ppm) (Note 1) mg/m3(ppm) (Note 1)NO 10 to 600 (0.
4、01 to 0.5) 0.6 to 30 (0.5 to 25)(NO+NO2)=NOx20 to 1000 (0.01 to 0.05) 1 to 50 (0.5 to 25)NO220 to 1000 (0.01 to 0.5) 1 to 50 (0.5 to 25)NOTE 1Approximate range: 25C and 101.3 kPa (1 atm).1.2 The test methods are based on the chemiluminescentreaction between nitric oxide and ozone.1.3 This standard d
5、oes 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-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specificprecautionary stateme
6、nts, see Section 9.2. Referenced Documents2.1 ASTM Standards:2D 1356 Terminology Relating to Sampling and Analysis ofAtmospheresD 1357 Practice for Planning the Sampling of the AmbientAtmosphereD 1914 Practice for Conversion Units and Factors Relatingto Sampling and Analysis of AtmospheresD 3195 Pra
7、ctice for Rotameter CalibrationD 3249 Practice for General Ambient Air Analyzer Proce-duresD 3609 Practice for Calibration Techniques Using Perme-ation TubesD 3631 Test Methods for Measuring Surface AtmosphericPressureE1 Specification for ASTM Liquid-in-Glass Thermometers2.2 Other Documents:29 CFR,
8、Part 1910, Occupational Safety and Health Stan-dards340 CFR, Parts 50 and 53, Environmental ProtectionAgencyRegulations on Ambient Air Monitoring Reference andEquivalent Methods33. Terminology3.1 Definitions:3.1.1 Four definitions of terms used in these test methodsrefer to Terminology D 1356 and Pr
9、actice D 3249.4. Summary of Test Method4.1 The principle is based upon the chemiluminescence, orthe emission of light, resulting from the homogeneous gasphase reaction of nitric oxide and ozone (1).4The equation isas follows:NO 1 O35 NO2* 1 O2(1)NO2* 5 NO21 hvIn the presence of excess ozone, the int
10、ensity of the lightemission is directly proportional to the nitric oxide concentra-tion.4.2 To measure nitric oxide concentrations, the gas samplebeing analyzed is blended with ozone in a flow reactor. Theresulting light emissions are monitored by a photomultipliertube.4.3 To measure total oxides of
11、 nitrogen (NOx=NO+NO2),the gas sample is diverted through a NO2to NO converterbefore being admitted to the flow reactor.4.4 To measure nitrogen dioxide (NO2), the gas sample isintermittently diverted through the converter, and the NOsignal subtracted from the NOxsignal. Some instrumentsutilize a dua
12、l stream principle with two reaction chambers.1These test methods are under the jurisdiction of ASTM Committee D22 on AirQuality and are the direct responsibility of Subcommittee D22.03 on AmbientAtmospheres and Source Emissions.Current edition approved Oct. 1, 2005. Published January 2006. Original
13、lyapproved in 1979. Last previous edition approved in 2000 as D 3824 - 95 (2000).2For referenced 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
14、 onthe ASTM website.3Available from Superintendent of Documents, U.S. Printing Office, Washing-ton, DC 20402.4The boldface numbers in parentheses refer to the list of references at the end ofthese test methods.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1
15、9428-2959, United States.5. Significance and Use5.1 Most oxides of nitrogen are formed during high-temperature combustion. The Environmental ProtectionAgency (EPA) has set primary and secondary air qualitystandards for NO2that are designed to protect the public healthand the public welfare (40 CFR,
16、Part 50).5.2 Oxides of nitrogen are generated by many industrialprocesses that can result in employee exposures. These areregulated by the Occupational Safety and Health Administra-tion (OSHA) which has promulgated exposure limits for theindustrial working environment (29 CFR, Part 1910).5.3 These m
17、ethods have been found satisfactory for mea-suring oxides of nitrogen in the ambient and workplaceatmosphere over the ranges shown in 1.1.6. Interferences6.1 The chemiluminescent detection of NO with ozone isnot subject to interference from any of the common airpollutants, such as O3,NO2, CO, NH3, a
18、nd SOx, normallyfound in the atmosphere (1). The possible interference ofhydrocarbons is eliminated by means of a red sharp-cut opticalfilter.6.2 The chemiluminescent detection of NO with O3issubject to positive interference from olefins (for example2-butene) and organic sulfur compounds (for exampl
19、e methanethiol) (2,3).6.2.1 Negative interference approaching 10 % may occur athigh humidities for instruments that have been calibrated withdry span gas (4).6.3 When the instrument is operated in the NO2or NOxmodes, any nitrogen compound decomposing to NO in theconverter or yielding products capabl
20、e of generating atomichydrogen or chlorine in the ozonator will produce a positiveinterference (2,5,6).6.3.1 Reported interferences are presented in Annex A8.Note that some organic sulfur species will positively interferein the NO mode, and negatively in the NO2mode.7. Apparatus7.1 Commercially avai
21、lable oxides of nitrogen analyzersshall be installed on location and demonstrated by the manu-facturer. Minimum performance specifications are shown inAnnex A1. The manufacturers shall verify that the instrumentmeets the specifications as determined by the test methods in40 CFR, Part 53.7.2 A simpli
22、fied schematic of the analyzer used in themethod is shown in Fig. 1. The principal components are asfollows:7.2.1 NOxConverterA device to reduce NO2to NO. Thisusually utilizes a stainless steel, molybdenum, or molybdenum-coated stainless steel coil at elevated temperatures. Conversionefficiency shal
23、l be at least 96 %.7.2.2 OzonatorA device that produces ozone for thechemiluminescent reaction.7.2.3 ReactorThe reaction chamber in which nitric oxideand ozone undergo the gas phase chemiluminescent reaction.7.2.4 PhotomultiplierA device used in conjunction with ared sharp-cut optical filter (600 nm
24、) (1) for measuring the lightoutput of the reaction between nitric oxide and ozone.(WarningThe photomultiplier tube may become perma-nently damaged if it is exposed to ambient light while the highvoltage is on.)7.2.5 PumpAdevice to provide a flow of gas (sample andozone) through the reaction chamber
25、 and to set the reactoroperating pressure for a given flow rate.7.2.6 Pressure Regulator for Standard NO CylinderAtwo-stage regulator to fit the NO cylinder, having internal partsof stainless steel with a TFE-fluorocarbon or polychlorotrifluo-rethylene seat and a delivery pressure of 200 kPa (30 psi
26、). Itshall contain a purge port or purge assembly to flush theregulator and delivery systems after connecting the regulatorsto the NO cylinder, but before the cylinder valve is opened.7.3 Zero and Span Calibrator, containing an NO2perme-ation device (see Practice D 3609), a means of controlling theF
27、IG. 1 Schematic of NO-NOxChemiluminescence MonitorD 3824 95 (2005)2temperature of the permeation device to 60.1C, flow control-lers, flowmeters, and an air pump. It shall include means ofcontinually flushing the permeation device with pure nitrogengas that has been passed through a drying tube conta
28、ining amixture of molecular sieve and indicating calcium sulfate.7.4 Gas Phase Titration Apparatus:7.4.1 GeneralThe apparatus consists of flow controllers,flowmeters, ozone generator, reaction chamber, and mixingchamber (see Fig. 2).7.4.2 Air Flowmeters, capable of measuring air flows be-tween 0 to
29、10 L/min with an accuracy of 62%.7.4.3 Nitric Oxide Flowmeters, capable of measuring nitricoxide flow between 0 to 100 mL/min.7.4.4 Soap Bubble Flowmeter, for calibrating the NO flow-meter with an accuracy of 62%.7.4.5 Ozone Generator, consisting of a quartz tube fixedadjacent to a low-pressure merc
30、ury vapor lamp capable ofemitting ultraviolet light of 185 nm. The concentration ofozone is controlled by adjusting the generator as specified bythe manufacturer.7.4.6 Reaction ChamberA borosilicate glass bulb (aKjeldahl bulb is satisfactory) (seeAnnexA2 for choosing size).7.4.7 All interconnections
31、 in the gas phase titrator shall bemade with glass and TFE-fluorocarbon.7.5 Air Purifier, to purify ambient air for use in the zero andspan calibrator and in the gas phase titration apparatus. Itconsists of an indicating silica gel trap to remove moisture, anozone generator to convert nitric oxide t
32、o nitrogen dioxide, anda trap containing activated coconut charcoal and molecularsieve. The purifier shall deliver air containing no more than 2.5g/m3of NO (0.002 ppm), 4 g/m3of NO2(0.002 ppm), and4 g/m3of O3(0.002 ppm).7.6 Temperature Sensor to Measure AmbientTemperatureAn ASTM low aniline point th
33、ermometer hav-ing a range from 38 to +42C and conforming to therequirements for Thermometer 33C as prescribed in Specifi-cation E1will meet the requirements of most applications.7.7 Barograph or Barometer, capable of measuring atmo-spheric pressure to 60.5 kPa (see Test Methods D 3631).7.8 Ozone Ana
34、lyzer, chemiluminescent or ultraviolet, meet-ing the requirements of 40 CFR, Part 50.7.9 Strip Chart Recorders, three, for use during calibration.8. Reagents and Materials8.1 Primary Standard (either 8.1.1 or 8.1.2 is satisfactory):8.1.1 Nitric Oxide Standard Cylinder, traceable to NationalInstitute
35、 of Standards and Technology (NIST) Reference Ma-terial SRM-1683 cylinder containing 60 mg/m3(50 ppm) of NOin N2, or SRM-1684a cylinder containing 120 mg/m3(100ppm) of NO in N2.8.1.2 Nitrogen Dioxide Standard Permeation Device, trace-able to NIST Reference Material SRM-1629.8.2 Nitric Oxide Working
36、Cylinder, containing from 60 to120 mg/m3(50 to 100 ppm) NO in oxygen-free nitrogen andless than 2 mg/m3(1 ppm) of NO2.8.3 Nitrogen Dioxide Permeation Device, for use in zeroand span calibration.8.4 Nitrogen, zero nitrogen, oxygen-free, containing lessthan 10 g/m3of NO or 20 g/m3of NO2(0.01 ppm).8.5
37、Molecular Sieve, type 4E, 6 to 14 mesh.8.6 Calcium Sulfate, indicating.8.7 Activated Coconut Charcoal, 6 to 14 mesh.8.8 Silica Gel, indicating, 6 to 14 mesh.FIG. 2 Schematic Diagram of a Typical GPT Calibration SystemD 3824 95 (2005)39. Precautions9.1 The handling and storage of compressed gas cylin
38、dersand the installation and use of the analyzer shall followPractice D 3249. Cylinders shall not be exposed to directsunlight.9.2 The exhaust from the analyzer may contain high con-centrations of ozone if the internal scrubber of the analyzerfails or becomes exhausted. For this reason, vent the exh
39、austfrom the vicinity of the analyzer and work area.9.3 Vent excess gases from calibrations outside the workarea and downwind of the sample probe.9.4 Purge the NO cylinder regulators with nitrogen usingthe purge port or assembly before opening the NO cylindervalve.9.5 The NO and NO2SRMs are not inde
40、finitely stable withtime; the stated concentration will change. They shall not beused for a longer period of time than that recommended in theircertificate.10. Sampling10.1 GeneralFor planning sampling programs, refer toPractices D 1357 and D 3249.10.2 When sampling the outside ambient atmosphere fr
41、oman enclosure with an ambient monitor, utilize a TFE-fluorocarbon or borosilicate probe or sampling line. Extend theprobe at least 1 m 3 ft from the building and protect it againstthe entry of precipitation. Utilize a TFE-fluorocarbon in-linefilter of 0.5-mm pore size to remove particulates from th
42、e airstream. Heat the portion of the probe inside the building toprevent condensation.11. Calibration and Standardization11.1 Analyzer:11.1.1 For calibration procedures, refer to Annex A2 andAnnex A3.11.1.2 Frequency of CalibrationPerform a complete cali-bration once a month.11.2 Flowmeters:11.2.1 C
43、alibrate the flowmeters of the zero and span cali-brator and the gas phase titration apparatus in accordance withPractice D 3195.11.2.2 Calibrate any flow orifice with a flowmeter that hasbeen calibrated in accordance with Practice D 3195.11.2.3 Perform the calibrations in 11.2.1 when the flowme-ter
44、s are received, when they are cleaned, and when they showsigns of erratic behavior.11.2.4 Perform the calibration in 11.2.2 when the analyzersare received and when the orifices are cleaned or replaced.11.3 Zero and Span Calibrator:11.3.1 Calibrate the zero and span calibrator in accordancewith Annex
45、 A4.11.3.2 Perform the calibration when the nitrogen dioxidepermeation device is received and every month thereafter.11.4 Certification of NO CylinderProcedures for certify-ing NO working cylinder against an NIST traceable NOcylinder or NIST traceable NO2permeation device are given inAnnex A7.12. Pr
46、ocedure12.1 After proper calibration has been established, allow theanalyzer system to sample the atmosphere to be tested.12.2 Take the recorder output and determine the concentra-tion of NO, NOx,orNO2directly from the calibration curves inparts per million.12.3 Check the NO2converter efficiency eve
47、ry month inaccordance with Annex A5.12.4 Perform a zero and span check daily in accordancewith Annex A6.12.5 Check the flow rates of all gases in the calibrator dailywith the flowmeters and adjust if necessary.12.6 Check the indicating drying tubes weekly and replacewhen the color indicates that 75
48、% of the capacity of the dryingmaterial has been reached.12.7 Replace all nonindicating drying tubes every threemonths.12.8 Replace the aerosol filter in the sampling line weekly.12.9 Check the paper and ink supply in the recorder daily.13. Calculations13.1 The signal output of the analyzer is gener
49、ally displayedon a potentiometric recorder and is read directly in parts permillion.13.2 To convert ppm to g/m3or mg/m3, refer to PracticeD 1914.14. Precision and Bias14.1 Precision: (7)14.1.1 The within-laboratory relative standard deviation hasbeen found to be 6 % of the NO2concentration over the range75 to 300 g NO2/m3(0.04 to 0.16 ppm), based on 1-h averages(7).14.1.2 The between-laboratories relative standard deviationhas been found to be approximately 14 % over the same range,based on 1-h averages (7).NOTE 2The stated precision data are for NO2modes
