On January 1, 2011, the Accuracy Audit Levels in AQS will be changing.
The memo “Use of Expanded List of Audit Levels for Annual Performance Evaluation for SO2, NO2, O3 and CO as described in 40 CFR Part 58 Appendix A Section 3.2.2” was issued on November 10, 2010.
(https://www.epa.gov/ttn/amtic/files/ambient/pm25/datamang/TechMemoforPEAuditLevels.pdf) The memo expands the audit levels for the gaseous pollutant annual performance evaluations to ten levels so as to better reflect the spread of the routine ambient air data being collected.
What does this mean in AQS?
Currently, AQS supports the reporting of data in five audit levels. Table 1 has the current AQS audit level concentrations.
|
Audit Level |
|
Concentration Range, ppm |
|
|
|
O3 |
SO2 |
NO2 |
CO |
|
|
1 |
0.02-0.05 |
0.0003-0.005 |
0.0002-0.002 |
0.08-0.10 |
|
2 |
0.06-0.10 |
0.006-0.01 |
0.003-0.005 |
0.50-1.00 |
|
3 |
0.11-0.20 |
0.02-0.10 |
0.006-0.10 |
1.50-4.00 |
|
4 |
0.21-0.30 |
0.11-0.40 |
0.11-0.30 |
5-15 |
|
5 |
0.31-0.90 |
0.41-0.90 |
0.31-0.60 |
20-50 |
For the near-term, there will continue to be five levels, but the concentration ranges of these five existing audit levels will change. The new concentration ranges defined within AQS will match the first four levels described in the November 10, 2010 memo, while the fifth level in AQS will encompass levels 5 – 10. Table 2 contains the new audit level concentrations, effective January 1, 2011.
|
Audit Level |
|
Concentration Range, ppm |
|
|
|
O3 |
SO2 |
NO2 |
CO |
|
|
1 |
0.004-0.0059 |
0.0003-0.0029 |
0.0003-0.0029 |
0.020-0.059 |
|
2 |
0.006-0.019 |
0.0030-0.0049 |
0.0030-0.0049 |
0.060-0.199 |
|
3 |
0.020-0.039 |
0.0050-0.0079 |
0.0050-0.0079 |
0.200-0.899 |
|
4 |
0.040-0.069 |
0.0080-0.0199 |
0.0080-0.0199 |
0.900-2.999 |
|
5 |
0.070-0.089 |
0.0200-0.0499 |
0.0200-0.0499 |
3.000-7.999 |
|
0.090-0.119 |
0.0500-0.0999 |
0.0500-0.0999 |
8.000-15.999 |
|
|
0.120-0.139 |
0.1000-0.1499 |
0.1000-0.2999 |
16.000-30.999 |
|
|
0.140-0.169 |
0.1500-0.2599 |
0.3000-0.4999 |
31.000-39.999 |
|
|
0.169-0.189 |
0.2600-0.7999 |
0.5000-0.7999 |
40.000-50.000 |
|
|
0.189-0.259 |
0.8000-1.000 |
0.8000-1.000 |
50.000-60.000 |
|
For the longer-term, AQS will be revised to accept /evaluate all 10 levels. Expanding the number of audit levels will affect AQS reports (e.g., AMP255 Data Completeness). Once fields for levels 6 - 10 are available in AQS, any performance evaluation (PE) concentration data that is submitted to AQS and that is associated with those levels would be properly reported in the AMP255 report. Therefore, in the future, the use and submission of the audit data at all levels will be accepted in AQS.
More information on the implications of this longer-term audit level expansion will be forthcoming.