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Environmental Protection Agency Blind Audit 2018



Christina Cecelski, Cassie Goodman, Jennifer Carney


The U.S. Environmental Protection Agency (EPA) conducted a blind audit of EPA protocol calibration gas mixtures produced by specialty gas manufactures. The objective was to determine the amount-of-substance fraction (concentration) of the analytes in the mixtures, and to compare the quantified values with those stated in the producers' certificates. The mixtures included in this audit consisted of carbon dioxide (CO2) at 8 % mol/mol to 18 % mol/mol; nitric oxide (NO) at 50 µmol/mol to 800 µmol/mol (ppm) [with total oxides of nitrogen (NOx) within 1 % relative of NO]; and sulfur dioxide (SO2) at 75 µmol/mol to 900 µmol/mol (ppm). The quality of these calibration mixtures is critical for the accurate determination and reporting of regulated gaseous emissions.
PGVP Audit Results


EPA Audit, PGVP, EPA Protocol Gas Mixtures, Protocol Gas Verification Program


Cecelski, C. , Goodman, C. and Carney, J. (2021), Environmental Protection Agency Blind Audit 2018, PGVP Audit Results, [online],, (Accessed June 21, 2024)


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Created May 17, 2021, Updated November 29, 2022