NARSTO Measurement Methods Compendium

NO2 Methods
  1. NO2

    1. Chemiluminescence after NO2 conversion to NO - (FRM)
      1. Basis: Chemiluminescence is the technique used to measure an analyte by mixing it with a species with which it reacts to form light. The intensity of the light is proportional to the concentration of the analyte and can be measured. Ambient air is flooded with excess ozone, which reacts with NO to produce excited NO2. The NO2 emits a photon as it returns to ground state. The NO2 in a second ambient air sample is then reduced to NO by a converter. The new NO concentration can again be measured by chemiluminescence. The difference of the concentrations is the concentration of NO2.
      2. Range: 0.25 - 25 ppmv
      3. Minimum Detection Level: 0 .005 ppmv
      4. Operating Temperature: N/A
      5. Known Interference: Water vapor above 20 ppm concentration. NO2 to NO converter specific interference:
        1. Catalytic reduction using heated molybdenum - PAN (375°C, 450°C); ethyl nitrate; ethyl nitrite; HONO; HNO3 (350°C, 375°C, 450°C); methyl nitrate, n-propyl nitrate, n-butyl nitrate, nitrocresol (450°C)
        2. Catalytic reduction using heated stainless steal - NH3, CH3NH2, HCN, N2O (650°C)
        3. Reaction with CO over a gold catalyst surface - n-propyl nitrate; HNO3, N2O5, PAN (3,000 ppm CO over 300°C gold surface); HCN, NH3 (except in the presence of water vapor under 700°C)
        4. Reaction with iron sulfate (FeSO4) at room temperature - PAN, HONO, and other nitrogen-containing species (dry conditions)
        5. Reaction with carbon at 200°C - PAN (285°C), HNO3 (285°C), n-propyl nitrate, phosgene, trichloroacetyl chloride, chloroform, chlorine, hydrogen chloride, photochemical reaction products of perchloroethylene-NOx mixtures, photochemical reaction products of molecular chloride (Cl2)-NOx mixtures, photochemical reaction products of molecular chloride (Cl2)-methanethiol mixtures, methanethiol, ethanethiol, ethyl sulfide, ethyl disulfide, methyl disulfide, 3-methylthiophene, H2S, 2,5-dimethylthiophene, methyl sulfide, methyl ethyl sulfide
        6. Photolysis at 320-400 nm - HONO; NO3; HO2NO2; N2O5
      6. Notes of Interest: N/A
      7. Instrument - Manufacturer:
        1. Advanced Pollution Instrumentation, Inc. Model 200 NO2 Analyzer - Advanced Pollution Instrumentation, Inc.
        2. Advanced Pollution Instrumentation, Inc. Model 200A NO2 Analyzer - Advanced Pollution Instrumentation, Inc.
        3. Beckman Model 952-A NO/NO2/NOx Analyzer - Beckman Coulter
        4. Bendix Model 8101-B Oxides of Nitrogen Analyzer - Bendix Corporation (refer to ABB Process Analytics)
        5. Bendix/Combustion Engineering Model 8101-C Oxides of Nitrogen Analyzer - Bendix Corporation (refer to ABB Process Analytics)
        6. Columbia Scientific Industries Models 1600 and 5600 Analyzers - Columbia Scientific Industries
        7. Dasibi Model 2108 Oxides of Nitrogen Analyzer - Dasibi Environmental Corp.
        8. Environnement S.A. Model AC31M NO Analyzer - Environnement S.A.
        9. Horiba Instruments Model APNA-360 NO-NO2-NOx Monitor - Horiba Instruments Inc.
        10. Monitor Labs Model 8440E Nitrogen Oxides Analyzer - Monitor Labs Inc.
        11. Monitor Labs Model ML9841B - Monitor Labs
        12. Monitor Labs/Lear Siegler Model 8840 and Model 8841 Nitrogen Oxides Analyzer - Monitor Labs Inc.
        13. Monitor Labs/Lear Siegler Models ML9841 and ML9841 - Monitor Labs Inc.
        14. Wedding and Associates Model 1030 NO2 Analyzer - Wedding and Associates Inc. (a subsidiary of Thermo Environmental Instruments Inc.)
        15. Phillips Model PW9762/02 NO/NO2/NOx Analyzer - Phillips Electronic Instruments, Inc.
        16. Thermo Electron/Thermo Environmental Instruments Model 14 B/E and Model 14 D/E - Thermo Environmental Instruments Inc.
        17. Thermo Environmental Instrument Model 42 and 42C NO/NO2/NOx Analyzer - Thermo Environmental Instruments Inc.
      8. References: 1, 4, 5, 23 (Go to References)

    2. Differential Optical Absorption Spectrometry (DOAS) - (FEM)
      1. Basis: The wavelength of light where a distinct absorption peak occurs is determined for an analyte. A wavelength (lambda) on either side of the absorption peak is next determined. The intensity of a light source at wavelength (lambda) is measured and then the intensity is measured again after the light passes through the analyte. The difference of the intensities is proportional to the concentration to the analyte.
      2. Range: 0-500 ppbv
      3. Minimum Detection Level: 4 ppbv
      4. Operating Temperature: 20°C-30°C and an air temperature of -50°C-50°C
      5. Known Interference: Anything that interrupts the path of the laser will cause some interference (i.e., animals, cars, planes, etc.).
      6. Notes of Interest: DOAS is a long path measuring technique. Measurements can be made in an optical pathway from 1 to 10 kilometers.
      7. Instrument - Manufacturer:
        1. OPSIS Model AR 500 and System 300 Open Path Ambient Air Monitoring System for NO2 - manufactured by OPSIS AB of Sweden (available from ABB Power Plant Controls, Inc.)
      8. References: 1, 4, 8, 14, 15 (Go to References)

    3. Sodium Arsenite Method - (FEM)
      1. Basis: Ambient air is bubbled with an orifice bubbler through a solution of sodium hydroxide (NaOH). The NO2 is reduced to nitrite. The nitrite is reacted with sulfanilamide and N-1-napthylethylenediamine (NEDA) in acid media to form an azo dye. The dye can be analyzed with a spectrophotometer at 540 nm.
      2. Range: 30-150 ppbv
      3. Minimum Detection Level: 5 ppbv
      4. Operating Temperature: N/A
      5. Known Interference: NO and CO2 are known interferences but at concentrations far exceeding those found in ambient air. The role of SO2 as an interference has not been determined.
      6. Notes of Interest: The original manual FRM was the Jacobs-Hochheiser Method. The method was withdrawn in 1973 by the EPA and is now considered unacceptable for air sampling and analysis.
      7. Instrument - Manufacturer: This is a manual method.
      8. References: 1, 11 (Go to References)

    4. Sodium Arsenite Method Technicon II Automated Analysis System - (FEM)
      1. Basis: Ambient air is bubbled with an orifice bubbler through a solution of sodium hydroxide (NaOH). The NO2 is reduced to nitrite. The nitrite is reacted with sulfanilamide and N-1-napthylethylenediamine (NEDA) in acid media to form an azo dye. The dye can be analyzed with a spectrophotometer at 540 nm. This method is considered a continuous method because hardware is used to make continuous measurements of the concentration of NO2.
      2. Range: 30-150 ppbv
      3. Minimum Detection Level: 5 ppbv
      4. Operating Temperature: N/A
      5. Known Interference: NO and CO2 are known interferences but at concentrations far exceeding those found in ambient air. The role of SO2 as an interference has not been determined.
      6. Notes of Interest: The original manual FRM was the Jacobs-Hochheiser Method. The method was withdrawn in 1973 by the EPA and is now considered unacceptable for air sampling and analysis.
      7. Instrument - Manufacturer: No current information on Technicon could be located.
      8. References: 1, 11 (Go to References)

    5. TGS-ANSA - (FEM)
      1. Basis: Ambient air is bubbled with an orifice bubbler through a solution of triethanolamine, guaiacol, and sodium metabisulfite (TGS). The NO2 is reduced to nitrite and then reacted with sulfanilamide and 8-amino-1-naphthalene-sulfonic acid ammonium salt (ANSA) to form an azo dye. The dye is analyzed with a spectrophotometer at 550 nm.
      2. Range: 30-150 ppbv
      3. Minimum Detection Level: 8 ppbv
      4. Operating Temperature: N/A
      5. Known Interference: No interference from NH3, CO, formaldehyde, NO, phenol, O3, or SO2.
      6. Notes of Interest: The original manual FRM was the Jacobs-Hochheiser Method. The method was withdrawn in 1973 by the EPA and is now considered unacceptable for air sampling and analysis.
      7. Instrument - Manufacturer: This is a manual method.
      8. References: 1, 10 (Go to References)

For definitions of method description terms see the Annotated Method Description Outline and Definitions.

For more information on FRM/FEM instrumentation, visit the AMTIC Designated Methods -- NO2.

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