SO2 Precursor Gas Monitoring Training Overview

1
SO2 Precursor Gas Monitoring Training Overview

• Lewis Weinstock
• Solomon Ricks, U.S. EPA
• Office of Air Quality Planning and Standards

2
Outline

• Methodology
• Field test results
• Responses to Calibrations
• Burdens Creek SO2 Frequency Distribution
• Instrument Operations
• Summary

3
Why measure trace levels of SO2

• Objectives
• Emission strategy development
• Effectiveness of reduction strategies
• Validation of SO2 and sulfate modeling
  predictions
• Long term trends analysis
• Health effect studies

Need highly-sensitive ambient monitors deployed
around these areas to determine CAIRs effect on
SO2 and related species.
4
Trace Level Sampling Challenges (SO2)

• Performance challenges
• Lower noise for reduced LDL/MDL
• Reduced zero and span drift
• Increased rejection of interferences
• Trace level modifications
• Special band-pass filter to increase NO rejection
• Improved light baffling to reduce stray light
• More powerful UV source lamp
• Higher detector sensitivity
• Longer optical bench

5
Methodology (UV Light Path)
SO2 hv214nm SO2 SO2
SO2 hv330nm
6
Methodology (General Schematic)
General Diagram of a Precursor Gas SO2 Analyzer
7
Currently Available Trace-Level SO2 Options
Teledyne-API 100EU EQSA-0495-100
Thermo Electron 43C-TLE EQSA-0486-060 (new model
43i-TLE)
Ecotech EC9850T EQSA-0193-092
8
Testing Results FieldApril 2006
9
(No Transcript)
10
Recertified Environics calibrator
11
Recertified Environics calibrator
?
12
Burdens Creek Ambient Concentrations
Span Level
Precision Level
13
Burdens Creek Ambient Concentrations
14
Thermo 43C-TLE Diagnostic Parameters (5-11-07)
15
Instrument Operation
16
Interferences

• Hydrocarbons
• Fluoresces in a fashion similar to SO2 when
  exposed to UV light
• Removed through the hydrocarbon kicker
• Nitrogen oxide
• NO fluoresces in a spectral range close to SO2
• Band pass filter enhances NO rejection

17
SO2 Response due to NO interference