QA - 1 Pt QC

40 CFR Part 58 Appendix A section 3.2.1 requires the primary quality assurance organization (PQAO) to perform a quality control check at least once every 2 weeks at required ranges (0.01 - 0.1ppm for SO2, NO2 and O3; and 1 - 10 ppm for CO) on every automated gaseous monitor. The “check standard” is a gas concentration generated from standard reference materials. In the case of O3, the “check standard” concentration is generated using an ozone generator.

The monitors for which this assessment applies usually sample continuously and report hourly average values as raw data to AQS. When it is time to run the 1-Point QC check, the check standard is introduced in the monitor, and readings from the monitor recorded. The monitor concentration and the check standard concentration are reported to AQS for the monitor and date. A null data code is included on the raw data transaction for that hour if a routine observation cannot be made for the hour due to performing the 1-Point QC check, and will indicate that the 1-Point QC check was performed.

For 1-Point QC Checks, the known value of the check gas concentration is referred to as the Assessment Concentration on the transaction. The value indicated by the monitor as a result of sampling the standard reference gas is referred to as the Monitor Concentration on the transaction. (This should alleviate some of the confusion that arose from the terms “actual” and “indicated” on the deprecated RP and RA transactions.)

Examples:

QA - 1-Point QC transaction in default mode
QA|I|1-Point QC|0145|06|067|0010|42602|1|20200601|1|074|008|67.9|70||
QA - 1-Point QC transaction in Tribal mode
QA|I|1-Point QC|0009|TT|905|8001|44201|1|20200601|1|047|008|62.2|61.3||

Format

QA - 1-Point QC 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 = 1-Point QC

Always

Y

4

Performing Agency

Agency Code of organization performing assessment.

Must exist in AGENCIES reference table.

Optional; defaults to user agency

5

State Code / Tribal Indicator

The FIPS state code of the monitor, or “TT” to indicate that the next field on the transaction is a Tribal code.

Must exist in STATES Reference Table or be ‘TT’ for Tribal Site

Always

Y

6

County Code / Tribal Code

The FIPS County Code of the site. If the previous field on the transaction contains “TT”, then the Tribal Code of the site.

Must exist in COUNTIES (for state) or TRIBAL_AREAS Reference table

Always

Y

7

Site Number

Four digit number to uniquely identify site in county and/or tribe.

Must exist in SITES table with {State Code, county Code} or Tribal Code

Always

Y

8

Parameter Code

The AQS parameter code assigned to the monitor in AQS.

Must exist in PARAMETERS reference table.

Always

Y

9

POC

Parameter Occurrence Code: One or two digit number identifying a specific monitor for a parameter at the site.

Must exist in MONITOR table for non-Insert actions.

Always

Y

10

Assessment Date

Date that the assessment was performed

YYYYMMDD.

Always

Y

11

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

12

Monitor Method Code

The sampling methodology of the monitor being assessed.

Must exist in SAMPLING METHODOLOGIES reference table.

Insert

13

Reported Unit

Units associated with the assessment concentrations (Monitor Concentration and Check Standard Concentration).

Must exist in UNITS reference table, and unit code must be for Concentration units type.

Unless Delete

14

Monitor Concentration

The concentration value provided by the monitor being assessed.

Decimal.

Insert

15

Assessment Concentration

The value of the known gas standard concentration.

Decimal.

Insert

16

Null Code

Descriptive text similar to the null code on the RD transaction: e.g. A null code value is valid if it exists in the AQS list of qualifiers with the qualifier type of “NULL QC”.

Must be a valid Null Code.

Optional

17

Comment

Free form text describing the assesment or invalidation.

Text, up to 2000 characters.

Optional