Document rMzw8LB4dx490mG60O4dO8jv

AR226-2316 y Charles J Zarzecki ' 03/20/2003 08:08 A M To: Catherine A Barton/AE/DuPont cc: Subject R e lookee what I found 0 . Cathie, The uncertainty is about 2X. That goes either way. The numbers can be half what we got, or twice what w e got. U nless these papers specifically address averaging time periods, I don't know how they will help our position. Also, even though they can underpredict, the IS C model is inherently conservative, a s we have discussed. I'll take a look, though. Charlie Z. Catherine A Barton Catherine A Barton 03/19/2003 04:25 P M To: Charles J Zarzecki/AE/DuPont@DuPont cc: Subject: lookee what I found Charlie, D am it,. There are a few papers on the web that d iscu ss uncertaintly around G aussian models. I'm reading through them to see if they could be used to say the answ ers we've gotten could be x tim es lower, or something of that nature. If you don't mind, take a look and see if they m ake a case or if they're full of hot air. here are three references: http://www.chemalliance.org/Columns/lndustry/lnd9908l 6.asp#(1) http://www.air-dispersion.com/feature.html http://www.epa.gov/epaoswer/hazwaste/combust/chg-air.pdf EID747641