Performance Evaluation of SO₂ Monitoring Instruments

Continuous air monitoring sulfur dioxide (SO₂) instruments which employ the four measuring principles most commonly used by federal, state, and local air pollution agencies are discussed. These measuring principles are colorimetry, conductivity, coulometry, and flame photometry. The advantages and disadvantages of using analyzers which employ each of these principles for collecting air quality data are discussed. Definitions for performance parameters and suggested performance specifications for SO₂ analyzers are given.