1、Designation: D3824 12Standard Test Methods forContinuous Measurement of Oxides of Nitrogen in theAmbient or Workplace Atmosphere by theChemiluminescent Method1This standard is issued under the fixed designation D3824; the number immediately following the designation indicates the year oforiginal ado
2、ption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover procedures for the continuousdetermination of
3、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 (0.01 to 0.5) 0.6 to 30
4、(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 The values stated in SI units are to
5、 be regarded asstandard. No other units of measurement are included in thisstandard.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-priate safety and health practices and
6、 determine the applica-bility of regulatory limitations prior to use. For specificprecautionary statements, see Section 9.2. Referenced Documents2.1 ASTM Standards:2D1356 Terminology Relating to Sampling and Analysis ofAtmospheresD1357 Practice for Planning the Sampling of the AmbientAtmosphereD1914
7、 Practice for Conversion Units and Factors Relatingto Sampling and Analysis of AtmospheresD3195 Practice for Rotameter CalibrationD3249 Practice for General Ambient Air Analyzer Proce-duresD3609 Practice for Calibration Techniques Using Perme-ation TubesD3631 Test Methods for Measuring Surface Atmos
8、phericPressure2.2 Other Documents:29 CFR, Part 1910, Occupational Safety and Health Stan-dards340 CFR, Parts 50 and 53, Environmental Protection AgencyRegulations on Ambient Air Monitoring Reference andEquivalent Methods33. Terminology3.1 Definitions:3.1.1 Four definitions of terms used in these tes
9、t methodsrefer to Terminology D1356 and Practice D3249.4. 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 h
10、vIn the presence of excess ozone, the intensity 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 photomult
11、ipliertube.4.3 To measure total oxides of 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 NO1These test methods are un
12、der 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 April 1, 2012. Published May 2012. Originallyapproved in 1979. Last previous edition approved in 2005 as D3824 - 95 (2
13、005).DOI: 10.1520/D3824-12.2For 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 onthe ASTM website.3Available from Superintendent of
14、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 19428-2959, United States.signal subtracted from the NO
15、xsignal. Some instrumentsutilize a dual stream principle with two reaction chambers.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 t
16、o protect the public healthand the public welfare (40 CFR, 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 theind
17、ustrial working environment (29 CFR, Part 1910).5.3 These methods 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
18、any of the common airpollutants, such as O3,NO2, CO, NH3, and 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 (fo
19、r example2-butene) and organic sulfur compounds (for example 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 de
20、composing to NO in theconverter or yielding products capable 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
21、negatively in the NO2mode.7. Apparatus7.1 Commercially available 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 de
22、termined by the test methods in40 CFR, Part 53.7.2 A simplified 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 ste
23、el coil at elevated temperatures. Conversionefficiency shall 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 use
24、d in conjunction with ared sharp-cut optical filter (600 nm) (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 PumpA device to provide
25、a flow of gas (sample andozone) through the reaction chamber 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 polychlorotrifl
26、uo-rethylene seat and a delivery pressure of 200 kPa (30 psi). Itshall contain a purge port or purge assembly to flush theFIG. 1 Schematic of NO-NOxChemiluminescence MonitorD3824 122regulator and delivery systems after connecting the regulatorsto the NO cylinder, but before the cylinder valve is ope
27、ned.7.3 Zero and Span Calibrator, containing an NO2perme-ation device (see Practice D3609), a means of controlling thetemperature 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 nitrogeng
28、as that has been passed through a drying tube containing 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 Flowme
29、ters, capable of measuring air flows be-tween 0 to 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
30、 a quartz tube fixedadjacent to a low-pressure mercury 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 (a Kjel-dahl bulb is satisfactory) (see
31、 Annex A2 for choosing size).7.4.7 All interconnections 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 remov
32、e moisture, anozone generator to convert nitric oxide to 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
33、 Measure Ambient TemperatureTemperature measuring devices such as RTDs (ResistanceTemperature Devices), thermistors and organic liquid-in-glassthermometers meeting the requirements of specific applicationsmay be used.7.7 Barograph or Barometer, capable of measuring atmo-spheric pressure to 60.5 kPa
34、(see Test Methods D3631).7.8 Ozone Analyzer, 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 Cy
35、linder, traceable to NationalInstitute 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 Mater
36、ial SRM-1629.8.2 Nitric Oxide Working 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/m
37、3of NO or 20 g/m3of NO2(0.01 ppm).8.5 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 SystemD3824 1239. Precautions9.1 The handling and s
38、torage of compressed gas cylindersand the installation and use of the analyzer shall followPractice D3249. 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.
39、For this reason, vent the exhaustfrom 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 Th
40、e NO and NO2SRMs are not indefinitely 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 D1357 and D3249.10.2 When sampling the ou
41、tside ambient atmosphere froman 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
42、remove particulates from the 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 mon
43、th.11.2 Flowmeters:11.2.1 Calibrate the flowmeters of the zero and span cali-brator and the gas phase titration apparatus in accordance withPractice D3195.11.2.2 Calibrate any flow orifice with a flowmeter that hasbeen calibrated in accordance with Practice D3195.11.2.3 Perform the calibrations in 1
44、1.2.1 when the flowme-ters 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 calibrato
45、r in accordancewith Annex 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 ar
46、e given inAnnex A7.12. Procedure12.1 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 NO
47、2converter efficiency every 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
48、 color indicates that 75 % 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
49、 of the analyzer is generally displayedon a potentiometric recorder and is read directly in parts permillion.13.2 To convert ppm to g/m3or mg/m3, refer to PracticeD1914.14. 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 precisio
