Preliminary Results from Laboratory And Fiel Studies of Total Hydrocarbon (VOC) Analyzers and Discussion of the Application of ethod 25A Measurement..., 1998 Environmental Conference Proceedings

David H. Word

Leon J. Larson

Richard W. Law

NCASI

The definition and measurement of volatile organic compounds (VOC) in the wood products industry have been issues of considerable debate for over a decade. This paper explores some of the issues involved in measurement of VOCs and provides preliminary results of experiments designed to provide information that will assist in development of a VOC sampling protocol for wood products sources. The results of experiments to determine the effects of calibration gas and gas diluent, oxygen synergism, and stack moisture are presented. The results indicate that stack or sample vent moisture concentrations create bias in flame ionization detector (FID) based VOC analyzers. Furthermore, the choice of calibration gas, and calibration gas diluent, affects VOC measurements. It is suggested that a hydrocarbon gas in an air diluent be used for sources with near ambient levels of oxygen. Methane and propane responded differently in the two analyzers tested. The choice of hydrocarbon used as a calibration gas can have some effect on VOC measurements. A sampling system that reduces the effect of moisture on VOC analyzers is discussed and provided in a figure.