"Ziman, Steve (SDZI)" <SDZI@chevrontexaco.com>
	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.  

 <<Long term measurement document update.rtf>> 



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