Draft Modeling Guidance for PM2.5 Available for Comment

Draft modeling guidance documents incorporating proposed requirements for modeling of particulate matter with a diameter less than or equal to 2.5 microns (PM2.5) have been posted on the Air Quality Bureau website at:

www.iowacleanair.com/prof/tech/tech.html#DISPERSION

The effected modeling guidance documents include the Prevention of Significant Deterioration (PSD) air dispersion modeling guidance and the non-PSD air dispersion modeling guidance documents. These documents contain the same proposed changes that were reviewed and discussed with attendees at the Air Quality Client Contact meeting May 22, 2008.

Comments on the changes proposed in the draft guidance documents may be provided to Lori Hanson at lori.hanson@dnr.iowa.gov or at (515) 281-8911, or to Jim McGraw at jim.mcgraw@dnr.iowa.gov or at (515) 242-5167. Any ideas or suggestions regarding how PM2.5 background values could be calculated for modeling purposes would also be helpful. Comments should be provided on or before Monday, June 23, 2008.