From:	Ziman, Steve - <SDZI@chevron.com>

To:	RTP3.RTMU538(blais-gary),RTPMAINHUB.INTERNET("sand...

Date:	10/18/96 10:34am

Subject:	review of PM design. options paper

FROM: Ziman, Steve -SDZI

DATE: 10/18/96 07:31

TO: OPEN ADDRESSING SERVI-OPENADDR

CC:

SUBJECT: review of PM design. options paper

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10/17/96

David Sanders: Here are my comments on this paper. You can distribute them to those STWG members who are part of the review of this, or to all the group.

Steve Ziman

cc: Gary Blais-EPA

Review of Options for Designating PM-fine Areas:

Background Section:

Para. 1: Statement that three years are necessary to provide a stable target. David Chock has already commented on this issue, and pointed out that the 24 hour standard is still an extreme value standard. Moreover, based on analyses done for the Central California Regional PM Air Quality

Study, it appears that the fine PM-10 concentrations (as well as the coarse

PM-10 concentrations) are subject to significant climatological influence.

In particular, drought versus non drought cycle has the direct affect on:

fugitive dust-the moisture content of the soil and therefore the degree that mechanical degradation of the soil into fugitive dust can occur. fine aerosol, especially secondary aerosol formation-depending on the timing of fronts moving through an area, buildup of secondary aerosol may not proceed to a level that triggers a standard violation. The last few years in the San Joaquin Valley have had lower values of the 24 hour standard than prior dry years.

Para. 3: As noted, there is no reference method. However, the draft methodology that has been discussed raises some significant questions with respect to it being able to provide an adequate characterization of both mass and species. This is due in part to the potential to have both positive and negative artifacts associated with volatilization and particulate formation on the filter. Unless the methodology is designed to account for these measurement problems, the data will be insufficient to define compliance, much less provide information for implementation decisions.

Options:

Ratio Method: There is a real question that the ratio method, especially on a 24 hour standard, can even attempt to simulate what is there. I think, if anything, that statement is a con statement. Further, the con statements are all correct, but need reinforcement. Essentially, there is little technical justification of using ratios without much more data than now available or even available for one year for minimal sites.

Unclassifiable Method: The con statement on ignores public health needs to be questioned. There are a number of controls implemented for ozone that may have the potential to reduce fine particles. The author should look at these and determine what we are getting from present Title I, II, III and IV programs. In addition, the present requirements for the PM-10 standard will still be in effect, and some of those will speak directly to both fine and coarse PM. Thus, it is also questionable as to whether the comment on sends mixed message is appropriate.

One Year Method: The pros and cons are OK as is. However, the term actual data negates the issue of the potential for the federal reference method to be flawed per above comments.

AOI Method: First, the assumption that we have regional problems is still very questionable on a overall basis. There needs to be specific analyze to determine which areas, based on real data (air quality, meteorology, emissions) any assumption of regionality is applicable. The present data is not sufficient to do so. Thus, I would question the bias of both of the pros- and the entire idea of AOIs

Modeling and Monitoring Method- There are no available models that have been evaluated for ability to predict secondary aerosol on an episodic basis. In point of fact, there is no guidance on what constitutes evaluation. Attempts to use UAM-Aero as part of the South Coast PM program showed that the state of science is not yet there. Further, even if the model(s) exist, the lack of sufficient emissions and ambient air quality and meteorological data does not allow one to have any confidence in using models for designations. I suggest this option be deleted.

Integration Implications: As previously noted in the conceptual model write up, and Rich Scheffe s summary, as well as comments on integration, it is not clear that there is integration of these pollutants in general. Rather, integration should be thought of as an opt-in process-only proceed with this if the area specific data justifies it. With respect to delay of new control strategies in the con section, see above comments on ignores public health problems in the unclassifiable section.

The bottom line is that there is not sufficient technical information or tools to meet a legal deadline. The time frame is inconsistent with the science. Determination of how to deal with that is a policy issue.