QA - AA-PGVP

AA-PGVP = Ambient Air Protocol Gas Verification Program.

The basic principles of the U.S. Environmental Protection Agency (EPA) Traceability Protocol for the Assay and Certification of Gaseous Calibration Standards (EPA, 1997) were developed jointly by EPA, the National Bureau of Standards (now National Institute of Standards and Technology [NIST]), and specialty gas producers over 30 years ago. At the time, commercially prepared calibration gases were perceived as being too inaccurate and too unstable for use in calibrations and audits of continuous source emission monitors and ambient air quality monitors. The protocol was developed to improve their quality by establishing their traceability to NIST Standard Reference Materials (SRMs) and to provide reasonably priced products. This protocol established the gas metrological procedures for measurement and certification of these calibration gases for EPA’s Acid Rain Program under 40 Code of Federal Regulations (CFR) Part 75, for the Ambient Air Quality Monitoring Program under 40 CFR Part58, and for the Source Testing Program under 40 CFR Parts 60, 61, and 68. EPA required monitoring organizations implementing these programs (“the regulated community”) to use EPA Protocol Gases or NIST standards as their calibration gases. 40 CFR Part 58 Appendix A includes the following language.

2.6 Gaseous and Flow Rate Audit Standards. Gaseous pollutant concentration standards (permeation devices or cylinders of compressed gas) used to obtain test concentrations for CO, SO2, NO, and NO2 must be traceable to either a National Institute of Standards and Technology (NIST) Traceable Reference Material (NTRM), NIST Standard Reference Materials (SRM) and Netherlands Measurement Institute (NMi) Primary Reference Materials (valid as covered by Joint Declaration of Equivalence) or a NIST-certified Gas Manufacturer’s Internal Standard (GMIS), certified in accordance with one of the procedures given in reference 4 of this appendix. Vendors advertising certification with the procedures provided in reference 4 of this appendix and distributing gases as “EPA Protocol Gas” must participate in the EPA Protocol Gas Verification Program or not use “EPA” in any form of advertising.

In 1997, EPA revised the protocol to establish detailed statistical procedures for estimating the total uncertainty of these gases (EPA, 1997). The acceptance criterion that is required for EPA’s Acid Rain Program (EPA, 1993) is for the total uncertainty to be less than +/- 2.0 percent. Although not specified in CFR the AA-PGVP established an acceptance goal of 4%.

In 2009 EPA-OAQPS and EPA Region’s 2 and 7 developed the Ambient Air Protocol Gas Verification Program (AA-PGVP). This program is expected to:

  • ensure that producers selling EPA Protocol Gases participate in the AA-PGVP and

  • provide end users with information about participating producers and verification results.

This program is considered a verification program because its current implementation level does not allow for a large enough sample size of EPA Protocol Gases from any one specialty gas producer to yield a statistically rigorous assessment of the accuracy.

The program is implemented by monitoring organizations who purchase a cylinder from the specialty gas producer and send the new, unused gas cylinder to the Region 2 or Region 7 laboratory. This process will allow for a submission that is “blind” to the producer. However, if EPA does not receive cylinders from a producer that is used by a monitoring organization, then EPA has to contact producers directly for cylinder submission.

Format

QA - Ambient Air Protocol Gas Verification Program transaction format

Seq.

Name

Description

Formatting Rules

Required

Key

1

Transaction Type

Quality Assurance transaction identifier.

Must = QA

Always

2

Action Indicator

Indicator for Insert, Update, or Delete action.

Must = I, U, or D

Always

3

Assessment Type

Indicates the specific QA assessment associated with the transaction.

Must = AA-PGVP

Always

Y

4

Performing Agency

Agency Code of organization performing assessment.

Must exist in AGENCIES reference table.

Always

Y

5

Producer ID

Unique identifier of organization that produced cylinder being assessed.

Must exist in AAPGVP PRODUCERS reference table.

Always

Y

6

Cylinder ID

Unique identifier (e.g. serial number) of gas cylinder being assessed.

Text (up to 40 characters).

Always

Y

7

Parameter Code

The AQS parameter code assigned to the monitor in AQS.

Must exist in PARAMETERS reference table.

Always

Y

8

Assessment Date

Date that the assessment was performed

YYYYMMDD.

Always

Y

9

Assessment Number

A unique number associated with an assessment performed at a site on a given day. Value should be “1” unless additional same assessments are performed.

Integer.

Always

Y

10

Reported Unit

Units of measure of analyte by Lab.

Must exist in UNITS reference table.

Unless Delete

11

Cylinder Certified Concentration

Gas concentration specified by cylinder producer.

Decimal, positive.

Insert

12

Assessment Concentration

Measured concentration of gas in cylinder.

Decimal, positive.

Insert