Document n9D4e6pDwm70qqaB9J8OyO9jR

AR226-2313 David M Rurak 03/16/2003 07:01 PM To: Catherine A Barton/AE/DuPont@ DuPont ce: Mark C Hause/DuPont@ DuPont, Charles J Zarzeeki/AE/DuPont@ DuPont Subject Re: ISC Model Q C ath y, I am not suggesting the model Is being used inappropriately, it has provided valuable input. W hat I am looking fo r are documented limitations o f the m odel. For instance, does it handle particulates and aerosols or m aterials that behave in both m anners. Thanks, Dave Catherine A Barton g r Catherine A Barton 03/12/2003 04:39 PM To: Mark C Hause/DuPont@ DuPont ec: David M Rurak/AE/DuPont@ DuPont, Charles J Zarzecki/AE/DuPont@ DuPont Subject Re: ISC Model Q j " Dave, Recall that we gave O hio EPA our reference for how we are doing the m odeling. That reference is EPA's Guideline on a ir Q uality Models in 40 CFR 51Appendix W (you can find it at this link: http://www.epa.gov/scram001/guidance/guide/appw__01 .pdf). If you scroll down to the bottom o f the 50th page (page 435 on the docum ent) you will see a sum mary of the ISC m odel. Here is an excerpt: a. Recommendations for Regulatory Use ISC 3 is appropriate for the following uses: Industrial source com plexes Rural or urban areas Flat or rolling terrain Transport distances less than 50 kilometers O ne hou r to an n u al averagin g tim es Continuous toxic a ir emissions . There really isn't an argum ent to say the model is being used inappropriately. Sorry to be the bearer of bad news. -C a th ie Mark G Hause Mark C Hause 03/12/2003 04:25 PM EID747631 To: David M Rurak/AE/DuPont@ DuPont cc: Catherine A Barton/AE/DuPont@ DuPont, Charles J Zarzecki/AE/DuPont@ DuPont Subject: ISC Model Dave, P er our discussion, I have spoken with Cathie on the need to investigate th e model and its validity fo r 1 and 8 hour periods. She is investigating the documentation and w ill respond to you promptly. W ith regard to future work on modeling, in order to expedite communications, I suggest you com municate directly with Cathie and C harlie on this issue. Particularly since I will be travelling for the next several days. If there is anything that I can do to help, please let m e know. Thanks EID747632