Performance Characteristics of Stack Monitoring Instruments for Oxides of Nitrogen

Abstract

The experience of the New York State Division of Air Resources in conducting performance tests of NO_x monitoring instruments is reported and the data collected are presented. Four representative instrumental techniques were selected and evaluated: chemiluminescence, ultraviolet spectrophotometry, electrochemical transducer, and dispersive infrared spectrometry. The objective of this study was twofold: to provide objective information on the selection and use of instrumental methods, and to determine whether the current instrumental techniques are adequate for source testing purposes. Important aspects of the performance tests were to identify possible weaknesses in the measuring principle and design, and to make appropriate suggestions for improvement.

Field test results demonstrated that instrumental methods, together with an appropriate sample pretreatment system, should be seriously considered as a substitute for the phenoldisulfonic acid method for NO_x measurement from stationary combustion sources. Immediate research and development is recommended to design an optimized sample pretreatment system to suitably prepare the stack gas sample for the measurement of NO_x and other pollutants.