May 13, 1997

DRAFT ISSUE PAPER

New Sources:

Considerations for the Implementation of New Air Quality Standards/Regulations

Phase II Issues

Following are the major issues that were deferred to Phase II.

PM10/PM2.5 Issues

With the promulgation of a PM2.5 standard, EPA will need to consider PM2.5 increments for the Prevention of Significant Deterioration (PSD) program. As has been discussed in other issue papers, fine particulate modeling is in its infancy and emission factors for PM2.5 are lacking. Sufficient resources must be dedicated to the effort of developing and validating the model and emission factors before they can successfully be used as a permitting and regulatory tool. In addition, while ozone modeling has become more sophisticated over the past couple of years, there is still a significant gap in the knowledge of atmospheric chemistry and conversion to secondary fine particulates. EPA looked at adopting increments for ozone around 1980. Due to the complexity of the secondary phase transformation (i.e., VOC or NOx conversion to ozone), EPA elected not to promulgate ozone increments. If PM2.5 increments are proposed and promulgated, they would most likely be very small. Using the ranges proposed for the PM2.5 standard, the increments might look as follows (based on PM2.5/PM10 ratios and the process used to set the PM10 increments).

Class I	Class II

PM2.5 Annual	1 ug/m3	5 ug/m3

PM2.5 24-Hour	3 ug/m3	10 ug/m3

Options for consideration:

Do not propose or promulgate PM2.5 increments.

Do not propose or promulgate PM2.5 increments until such time as accurate models and emission factors are developed and validated. Retain the current PM10 increment program for now, but recognize that current models/emission factors are not adequate for some sources. Commit up front the necessary resources to develop accurate models and emission factors. Sufficient resources are also required for a monitoring program with which to validate the outputs of the models and emission factors, as well as resources to develop an accurate inventory.

Propose and promulgate PM2.5 increments. Commit up front the necessary resources to develop and validate accurate models and emission factors.

Do not develop PM2.5 increments for secondary particles. Delay development of PM2.5 increments until there are better data, emission factors and models. PM10 increments may serve as a surrogate until that time, recognizing that the current models and emission factors are not adequate for some sources. However, it must be recognized that PM2.5/PM10 ratios are highly variable, raising a concern over the validity of using PM10 as a surrogate.

The previous discussion has addressed PSD increments for PM10 and PM2.5 separately. This discussion was based on the assumption that PM2.5 and PM10 are separate pollutants. The whole discussion of the PSD program should also be considered in the overall context of current and upcoming regulatory programs.

Permitting

The adoption of new ozone and particulate standards (particularly a PM2.5 standard), as well as the promulgation or regional haze rules raises many questions about how new or modified sources will be permitted. If a market based trading program is adopted, modeling requirements might be appropriately reduced. Permitting, in its current form, may be limited to non-AOI's. Some options:

Each source will be required to conduct a modeling demonstration for each pollutant (for example, ozone, PM10, PM2.5, NOx, VOC's, SO2, ammonium nitrate, ammonium sulfate and regional haze). This permitting requirement would apply to all sources.

1.A. The permitting requirement discussed in (1) would only be required for sources that exceed existing thresholds for "significant" emissions.

1.B. The permitting requirement discussed in (1) would only be required for sources that exceed newly-established thresholds.

1.C. Note that there may be an incentive for some sources to reduce emissions in order to avoid a lengthy, expensive permitting process.

Allow for parametric quantification/engineering analyses in lieu of full source/receptor modeling. This option could apply to all sources, or to those sources under a certain threshold.

Request that the Science and Technology Work Group identify areas for consolidation of modeling demonstrations. For example, can a single model be developed that incorporates several pollutants, thereby decreasing the overall complexity of the permitting process. Guidance should also be sought on how to handle transport in the permitting process. For example, how should background be handled? Are the models accurate enough to use? Does monitoring data support the numbers generated by the models? With regard to the western United States, how should prescribed and natural fires be handled? Does there need to be a requirement to add emission inventories and meteorological fields, by season, for AOI's? There is a lack of stack test methods for some pollutants, particularly when transport and conversion to a particle are included. Do stack test methods need to be updated, or developed? Should both the coarse and fine particles be considered before a permit is granted?

This discussion of how to permit new or modified sources leads to the question of how to apply the permitting process for any new air quality standard between the time of promulgation of the standards and the time that the models/emission factors are deemed adequate for regulatory use. Some options:

Use available models and emission factors for permitting of new sources, regardless of whether or not the models/emission factors have been adequately tested for regulatory use.

Require new sources or major modifications of existing sources to undergo the current system of permitting until such time as the new models and emission factors are adequately reviewed and tested for regulatory use.

2.A. Same as (2), but require any new source permitted in this interim period to perform the modeling for the new air quality standards once the models/emission factors are deemed ready for regulatory use. This option substantially increases the uncertainty in the permitting process.

Fine Versus Coarse Particles

The EPA Staff Paper states "PM2.5 does have some potential for intrusion of the "tail" of the coarse mode during episodes of fugitive dust. Staff recommends a sharp inlet for the Federal Reference Method (FRM) to minimize this potential intrusion of coarse mode particles. Such intrusions in to PM2.5 measurements are not anticipated to be significant in most situations; nevertheless, if subsequent data reveal problems in this regard, this issue can and should be addressed on a case-by-case basis in the monitoring and implementation programs." Some considerations:

Do nothing and ignore coarse particle intrusion.

Recommend that EPA truly consider "coarse" and "fine" particles. For example, EPA states that coarse and fine particles should be considered as separate pollutants. One is comprised of crustal materials, while the other derives from combustion. Yet, a PM10 standard would include both coarse and fine particles. Consideration should be given t particle.

Consider adoption of a policy that adjusts the coarse particles in the PM2.5 fraction. Dr. Dale Lundgren with the University of Florida has developed a statistical approach to making this adjustment.