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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U.S. EPA Releases New Dispersion Modeling Guidance
Posted: September 12th, 2010
U.S. EPA’s Air Quality Modeling Group (AQMG) released guidance on the U.S. EPA Support Center for Regulatory Atmospheric Modeling (SCRAM) website. The first memorandum entitled “Applicability of Appendix W Modeling Guidance for the 1-hour SO2 NAAQS” was released in conjunction with the […]
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More Stringent SO2 NAAQS Finalized by U.S. EPA
Posted: June 27th, 2010
U.S. EPA has announced the promulgation of a new 1-hour National Ambient Air Quality Standard (NAAQS) for sulfur dioxide (SO2). The new 1-hour NAAQS level is 75 parts per billion (ppb) measured as the three year average of the 99th […]
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U.S. EPA Convenes RSL Modelers Workshop
Posted: June 18th, 2010
On May 10 – 13, U.S. EPA met with regional, state, and local modelers in Portland, Oregon for the U.S. EPA Regional/State/Local (RSL) Modelers Workshop. Several “hot-topic” items were included on the agenda, most notably, the new NO2 and SO2 […]
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Tightening the Screws – Lower NAAQS Mean Higher Costs
Posted: April 20th, 2010
ALL4’s Ambient Group continues to track and provide you with updates on the latest developments related to National Ambient Air Quality Standards (NAAQS). The NAAQS are the primary basis for the permitting of new stationary sources and modifications to stationary […]
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U.S. EPA Releases 1-Hour NO2 NAAQS Modeling Guidance
Posted: March 18th, 2010
The U.S. EPA Air Quality Modeling Group (AQMG) recently released a new guidance document for NO2 modeling. The document outlines procedures that can be used to calculate the NO2 design values for comparison to the new 1-hour NO2 National Ambient […]
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Air Modeling Dispersion Program Update
Posted: February 14th, 2010
The Air and Waste Management Association (AWMA) held a conference entitled Guideline on Air Quality Models: Next Generation of Models in Raleigh, NC from October 28 – 30, 2009. During the conference representatives from U.S. EPA’s Air Quality Modeling Group […]
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ALL4 Ambient Group Attends Modeling Conference
Posted: December 28th, 2008
On October 8 and 9, 2008, ALL4’s Ambient Group attended the 9th Conference on Air Quality Modeling in Research Triangle Park, NC, hosted by U.S. EPA. The conference provided an update on the latest developments in air quality modeling and […]
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