Software Release Notes

2010 NO2 and SO2 NAAQS revisions to AQS (Phase 1)

October 15, 2010

AQS will be unavailable October 15 – 18, 2010 due to system software changes.

1. The software changes will implement Phase 1 of the 2010 NO2 and SO2 NAAQS revisions to AQS.

   1. For NO2, these regulation changes were published in 40 CFR Part 50.11 (75 FR 6531) and Appendix S (75 FR 6532) on February 9, 2010.

   2. For SO2, these regulation changes were published in 40 CFR Part 50.17, (75 FR 35592) and Appendix T (75 FR 35595) on June 22, 2010.

2. Monitor-level summaries will be computed.

   1. Only the monitor-level summaries required by the regulations will be implemented in Phase 1.

   2. Site-level summarization (to compute the 3-year design values) will be implemented by Phase 2 of this project (expected completion 4^th quarter 2010.)

3. Standard units for NO2 and SO2 will change.

   1. The standard units for NO2 and SO2 will change from Parts per Million (ppm, unit code 007) to Parts per Billion (ppb, unit code 008).

   2. For NO2

Only parameter code 42602 (Nitrogen Dioxide) is affected.

(Other parameter codes - 42600 (Reactive Oxides of Nitrogen) and 42603 (Oxides of Nitrogen) - will be addressed by Phase 2.)

c. For SO2

Only parameter code 42401 (Sulfur Dioxide) with duration 1 (1-hour) and H (5minutes) is affected.

(Parameter code, 42406 (SO2 Max 5-minute Avg) will be addressed by Phase 2).

4. Measurement values in standard units (the "standard value") will be stored with one digit after the decimal; any additional digits will be truncated.

5. Summaries will be recomputed.

   1. All NO2 and SO2 summaries (daily, quarterly, annual, and 3-hour and 24-hour block averages for SO2) are being recomputed in units of ppb. 

6. AMP450 Quick Look Report changes:

   1. AMP450 Quick Look has been updated to reflect the new 1-hour standards and new units for both NO2 and SO2.

      1. NO2 report format now includes the 98th percentile.

      2. SO2 report format now includes the 99th percentile.

      3. Data for NO2 and SO2 are presented in ppb.

      4. Maxima and Percentiles are displayed with 1 digit after the decimal.

      5. Annual Means are displayed with 2 digits after the decimal.

   2. Quick Look workfile formats are changing.

      2. When multiple pollutants are selected, the NO2 and SO2 records will be separated into a different workfile, so that delimited (NO2, SO2) and fixedformat records (other pollutants) are not mixed.

      3. The data is formatted as a delimited file (rather than as a fixed-format file) and the delimiter (either a '|' or a ',') can be selected by the user.

      4. SO2 includes 99^th percentile

      5. NO2 includes 98^th percentile