2B Tech Model 211 Scrubberless Ozone Monitor for Interference-Free Measurements John Birks, Peter Andersen, Craig Williford & Andrew Turnipseed 2B Technologies, Inc. FEM/FRM Ozone Monitors in Monitoring Network  Ethylene Chemiluminescence (FRM, 0%)  UV Absorbance (FEM, >99%) • Teledyne API 400 series • Thermo-Fisher 49 series • Dasibi 1003/1008 • 2B Technologies 202, 205  NO + O Chemiluminescence (FEM, New FRM) 3 • Teledyne API Model T265  Scrubberless UV Absorbance (FEM, Candidate FRM) • 2B Technologies Model 211 Problem: Many Atmospheric Species Absorb at 254 nm e.g., Hg, Aromatics, Aldehydes & Ketones, Nitro Compounds Hg Line at 253.7 nm Example: Toluene Absorbs ~26 x less strongly than ozone at 253.7 nm 9 3 1 1.2 . 1 0 0 0 . 1 1 Absorbance Relative to Ozone 0.8 8 1 0.6 5 . 0 0.4 8 5 2 . 0 4 3 5 1 3 2 0.2 1 3 6 73 32 83 .0 90. 1.0 5 0 1 0 0 0 0 0 1 0 0 0 . . . 0 .0 .0 .0 0 0 0 .0 0 Response to p-Xylene using Different Ozone Scrubbers Relative Response to Mercury using Different Ozone Scrubbers Comparison of UV (FEM) with Ethylene CL (FRM) Ozone Measurements in Mexico City 30 ppb 8-hr Averages April 28, 1998 Azcapotzalco Mexico City UV: Thermo 49 CL: Bendix 8410 Alan R. Leston, Will M. Ollison, Chester W. Spicer and Jan Satola, “Potential Interference Bias in Ozone Monitoring” (2005) Air and Waste Management Association 55, 1464-1472. Conventional Ozone Monitor Scrubberless Ozone Monitor Schematic Diagram of Model 211 Ozone Monitor