An analyzer was developed for measuring motor vehicle NOx (NO and NO2) emissions based on the chemiluminescence reaction of NO and NO2 with hydrogen atoms. This eliminated the need for an NO2 to NO converter as required with ozone chemiluminescence for NOx analysis. The hydrogen-atom source is based on the thermal dissociation of molecular hydrogen on a hot (approximately 1900C) tungsten filament. The unit has linear response to NOx over a concentration range from 4 ppm to greater than 3000 ppm. No interferences were observed with H2O, CO, CO2, toluene, isopentane, NH3, HCN, CH3NH2, or H2 at concentrations encountered in raw automobile exhaust. Oxygen and ethylene caused minor interferences which should be inconsequential in actual application.

  • Corporate Authors:

    Aerochem Research Laboratories, Incorporated

    Emissions Measurement and Characteristics Division
    Durham, NC  United States  27709

    Environmental Sciences Research Laboratory

    Research Triangle Pk, NC  United States  27711
  • Authors:
    • Fontijn, A
    • Volltrauer, H N
    • Frenchu, W R
  • Publication Date: 1979-7

Media Info

  • Pagination: 43 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00312538
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: EPA/600/2-79/120
  • Contract Numbers: EPA-68-02-2744
  • Files: TRIS
  • Created Date: May 7 2002 12:00AM