What’s Going On With the 1-Hour SO2 NAAQS Implementation Process?
Posted: January 9th, 2012
Now that we’ve all had some time to digest the plethora of guidance memoranda and updated air quality modeling programs that were released in March and April of 2011 and summarized by ALL4 in our April 4 The Record article […]
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More Thoughts on SO2 NAAQS
Posted: November 20th, 2011
The public comment period for U.S. EPA’s draft dispersion modeling guidance for the 1-hour sulfur dioxide (SO2) National Ambient Air Quality Standard (NAAQS) is open until December 2, 2011. Since the guidance will lead to a significant and complicated undertaking […]
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NO2 NAAQS Implementation Status Quo (For Now)
Posted: August 19th, 2011
U.S. EPA has posted its responses to states’ initial designation recommendations for the new 1-hour nitrogen dioxide (NO2) National Ambient Air Quality Standard (NAAQS). Determining which areas are attaining or not attaining the 1-hour NAAQS will require the operation of […]
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U.S. EPA Regional, State, and Local Dispersion Modelers Workshop Slides Available
Posted: July 20th, 2011
U.S. EPA has made available the presentations from the U.S. EPA Regional, State, and Local Dispersion Modelers Workshop (Workshop)…
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ALL4 Attends U.S. EPA Regional, State, and Local Dispersion Modelers Workshop
Posted: June 13th, 2011
ALL4’s ambient group members Dan Dix and Colin McCall attended the U.S EPA Regional, State, and Local Dispersion Modelers Workshop (Workshop) held in Atlanta, GA on June 9, 2011. The annual meeting, which is hosted by the U.S. EPA Office […]
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Another Update to AERMOD!!
Posted: May 16th, 2011
On April 12, 2011 U.S. EPA’s Air Quality Modeling Group (AQMG) released another update to the AERMOD (now version 11103) air dispersion model on the Support Center for Regulatory…
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U.S. EPA Provides SO2 NAAQS “Implementation” Guidance
Posted: April 4th, 2011
On March 25, 2011, U.S. EPA released guidance on the implementation process for the 1-hour sulfur dioxide (SO2) National Ambient Air Quality Standard (NAAQS). The 1-hour SO2 NAAQS was promulgated in June 2010. As part of the NAAQS implementation process, […]
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Source Specific Ambient SO2 Monitoring vs. Air Quality Modeling for 1-Hour SO2 NAAQS Designations
Posted: March 26th, 2011
As part of the preamble of the new 1-hour sulfur dioxide (SO2) National Ambient Air Quality Standard (NAAQS), U.S. EPA outlined new NAAQS implementation procedures that will require certain facilities to be evaluated using refined air dispersion modeling with U.S. […]
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U.S. EPA Finalizes Key PM2.5 New Source Permitting Concentration Limits
Posted: November 23rd, 2010
U.S. EPA has finalized ambient PM2.5concentration limits that apply to projects undergoing Prevention of Significant Deterioration (PSD) permitting. The following thresholds have now been established for Class II areas…
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States are Planning to Model Major Facilities for SO2
Posted: September 24th, 2010
U.S. EPA promulgated a final 1-hour sulfur dioxide (SO2) National Ambient Air Quality Standard (NAAQS) on June 22, 2010. The new 1-hour NAAQS became effective on August 23, 2010. As described in ALL4’s May 2010 4 The Record, the new 1-hour […]
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