Accuracy Assessment of EPA Protocol Gases Purchased In 1991

Abstract

The U.S. Environmental Protection Agency (EPA) has established quality assurance procedures for air pollution measurement systems that are intended to reduce the uncertainty in environmental measurements. The compressed gas standards of the program are used for calibration and audits of continuous emission monitoring systems. EPA's regulations require that the certified values for these standards be traceable to National Institute of Standards and Technology (NIST) Standard Reference Materials or to NIST/EPA-approved Certified Reference Materials via either of two traceability protocols. The manufacturer assessment was conducted to: (1) document the accuracy of the compressed gas standards' certified concentrations; and (2) ensure that the compressed gas standards' written certification reports met the documentation requirements of the protocol. All available sources were contacted and the following gas mixtures were acquired: (1) 300-ppm SO2 and 400-ppm NO in N2; and (2) 1500-ppm SO2 and 900-ppm NO in N2.