"Ziman, Steve (SDZI)" 03/12/02 11:53 AM To: John Silvasi/RTP/USEPA/US@EPA cc: Subject: Follow Up to Yesterday's call John I plan to be in Phoenix for the next meeting. Assuming that you will be there, would it be useful to talk a bit the night before? I have talked with some of ChevronTexaco and API government affairs folks, and we will most likely provide written input after that meeting. There is one thing that I would like to have you think about, and I probably mentioned it already, but will do so again. It is clear to me that without a much improved air quality and meteorological monitoring network, any attempt to do mid course corrections, or to look at trends, or to provide much additional data for modeling and corroborative analysis will fail. Probably one of the more important lessons that we have drawn from the work now being done for the San Joaquin Valley bump up SIP is that we do not have enough data to really tell us why we have failed to make progress towards the ozone standard. Further, we recognize that, in order to understand how well any future strategy is working, and whether it is working efficiently, there is need for data. This will be true for other criteria pollutants. We recognize that modeling a few episodes, even with a robust data base, only allows a look at how the atmosphere responds for those worst case conditions. Yet, there will be significantly more 8-hr episodes than 1-hr episodes, and they will encompass a longer season, and therefore, different meteorological conditions. And it is not clear that the strategy for a worst case will work for these lesser episodes. One mechanism for trying to understand how the atmospheric processes vary for different episodes is to attempt to do seasonal modeling. But it can only be attempted with a much better routine database. And, given what we have learned about modeling, it must be done in conjunction with sufficient data analysis so that one at least has confidence that the direction (i.e., which precursor to reduce and where) is correct. I think I sent you the proposal that the San Joaquin Valley Study Agency Technical Committee has drafted and is trying to get implemented by the various local and state agencies here in California. In some ways it complements the ideas that Rich Scheffe is developing. But it is attached. I realize that there were real debates during FACA on monitoring, especially since many were concerned about it being used to identify new nonattainment areas. But without it, we will be in a world of hurt, and given the potential difficulty of some of the major CMSAs attaining the 8-hr standard, and also dealing with PM2.5, we need a better network. So, I urge you to consider pushing the states to implement a much better network, and perhaps having requirements for this if they are to do mid course corrections, and making much better trend reporting part of the guidance. <> Steve Ziman, Ph.D Senior Staff Scientist Air Issues; Health, Environment and Safety Group Chevron Research and Technology Co. 100 Chevron Way Richmond, California 94804 sdzi@chevrontexaco.com phone: 510-242-1530 fax: 510-242-5577