Presentation on theme: "SO2 Precursor Gas Monitoring Training Overview"— Presentation transcript:
1SO2 Precursor Gas Monitoring Training Overview Lewis WeinstockSolomon Ricks, U.S. EPAOffice of Air Quality Planning and Standards
2Outline Methodology Field test results Responses to Calibrations Burden’s Creek SO2 Frequency DistributionInstrument OperationsSummary
3Why measure trace levels of SO2 Objectives:Emission strategy developmentEffectiveness of reduction strategiesValidation of SO2 and sulfate modeling predictionsLong term trends analysisHealth effect studiesNeed highly-sensitive ambient monitors deployed around these areas to determine CAIR’s effect on SO2 and related species.
4Trace Level Sampling Challenges (SO2) Performance challengesLower noise for reduced LDL/MDLReduced zero and span driftIncreased rejection of interferencesTrace level modificationsSpecial band-pass filter to increase NO rejectionImproved light baffling to reduce stray lightMore powerful UV source lampHigher detector sensitivityLonger optical bench
15Instrument Operation Item Schedule Check diagnostics (if not available remotely)Bi-weeklyVisual inspection and cleaning6 monthsReplace sample particulate filterBi-weekly to monthly based on PM levelsPerform QC gas challenge (Level 1 and precision)Bi-weekly (daily recommended)Capillary inspection and replacementFan filter inspection and cleaning6 months depending on surroundingsLamp voltage checkWhen lamp voltage approaches maximum (1200v)
16Hydrocarbons Nitrogen oxide Interferences Fluoresces in a fashion similar to SO2 when exposed to UV lightRemoved through the hydrocarbon “kicker”Nitrogen oxideNO fluoresces in a spectral range close to SO2Band pass filter enhances NO rejection