DRAFT

Science and Technical Support Work Group

Issues and Work Products

I. Atmospheric Processes

[Conceptual Model: In order to develop an adequate understanding of PM formation in different areas of the country, it is very useful to develop a conceptual model of the processes that lead to PM. In setting out the initial model, there will be many more questions than available information can answer them. Consequently, the conceptual model will provide a mechanism to identify additional needed information. The entire process is iterative in nature, but provides an overall frame work for increasing the scientific and technical information needed to provide a basis for sound planning. In addition, the conceptual model can codify the processes independent of any air quality modeling, and thus provides an independent mechanism to evaluate the performance of the air quality model(s)

What critical data do we need to understand, evaluate and predict the concentrations of PM and O3 and the impairment from regional haze?]

Issues:

What are the transport mechanisms and how important are they for regional haze, PM and O3?

How do we determine what portion of the problem are natural, local generated or transported in?

If VOC reactivity is an important factor, how can it be determined and added in to the system?

How will data gaps/data quality (chemistry, meteorology, emissions, etc) be addressed?

What is the minimum acceptable modeling, monitoring and emissions data analyses need to characterize long range transport?

Secondary aerosol is a major component of PM2.5. Do we have sufficient knowledge of its formation to construct a credible PM control strategy?

Examine or model how regional haze, PM NAAQS, acid rain, and ozone programs could be integrated.

II. Modeling Formulation/Evaluation

[Modeling: Closely akin to the conceptual model.]

Issues:

How will a PM model be validated without ambient data?

Develop a conceptual model of the processes that lead to PM.

Will the model(s) be able to characterize PM concentrations which are comparable to the measurements produced by the Federal Reference Method (FRM).

Will the model(s) be able to characterize regional transport; assist with identifying culpable sources; provide information to assist with monitoring site selection?

How do we identify the uncertainty in the model outputs so that the information can be reasonably used and not misused?

How sensitive are the models to the uncertainty of the input data?

Does it make sense to emphasize the peak concentrations predicted by the models for attainment demonstration or is it better to use some averaging mechanism?

How will one determine the need for a common platform, what is sufficient input data, what is acceptable performance and how does one define "acceptable"?

How does a regional model become an EPA "guideline" model?

What is the relationship between urban and superregional modeling?

Do we need to, and if so, how do we improve the accuracy of biogenic emission measurements and inventories?

III. Ambient Monitoring and Data Analysis

[Monitoring: One issue not addressed is network design. That is, where do we place monitors, what information we seek from the monitors, the duration of monitoring, the types of monitors etc. The conceptual model, the data analysis, and any design of an intensive model data collection effort will help this effort. Additionally, there is a need to explicitly decide if the network design should take into account the idea of better characterizing ambient ozone and PM levels to be used for exposure assessment. Both of the standards are health based, yet the present guidance in 40 CFR 58 provides minimal support for this type of siting. Further, the present set of compliance criteria actively discourage adding monitors to a network.

All of these issues, as well as the ones identified in the memo sent to us prior to the conference call point out the lack of understanding that we now have about PM, as well as the lack of information and tools to carry out a technically sound assessment for PM and ozone (note, if we can t address these two criteria pollutants, we have little chance in making headway in regional haze). These issues need to be described in further detail, including the time it will take to develop the necessary information. It is critical that the other two work groups have a clear understanding as to what methodolgies and tools are or will be available prior to proposing specific regulations. Otherwise, we will repeat the problems that we are encountering with the present ozone planning process and regulations

Based upon existing PM data, how can we predict PM fine concentrations for a system of area designations and classifications?]

[Data Analysis: The work products item III, makes mention of data analysis, but there appears to be no clear statement of what will/should be done or how it fits into the overall frame work. Data analysis is often overlooked, but it is of prime importance. It provides the information to enhance a conceptual model, and provides specific independent analyses which can be used to compare to the inputs and outputs of the different air quality modules (emissions, meteorology, deposition, chemistry etc) and the air quality model as a whole. Based on experience in the San Joaquin Valley Air

Quality Study (ozone) and the Gulf of Mexico Air Quality Study (ozone), this independent comparison has been invaluable in leading to model improvements, or identifying uncertainties in the modeling results.

Particle mass concentration is an imprecise metric: seek out more precise technologies that characterize particle constituents (e.g., sulfate,nitrate, organics) and minimize adulteration caused by sampling techniques.]

Issues:

What does one design a network that accurately monitors VOC and NOx ratios?

Do we need to begin using monitoring networks for NH3?

Since monitoring with the Federal Reference Method (FRM) will be required by the monitoring regulations and not subject to FACA input, then; how can we supplement monitoring by the Federal Reference Method (FRM) and improve the monitoring networks?

- make it more real time

- make it cost efficient

- expand the coverage

Where do we place monitors, what types of monitors should be used, what information do we seek from monitors, what duration of monitoring is necessary?

How does one determine the appropriate episode to model, given different pollutants, averaging times, frequency of important modeling conditions (i.e., health responses), temporal and spatial emissions changes, meteorological and transport patterns, etc.

.What role (if any) will receptor modeling play in the PM fine implementation program?

IV. Emission Measurements and Inventories

[Concept: TBD]

Issues:

How will equitable (meaning like quality) multi-pollutant emission inventories (gridded data sets) be established for use with multi-pollutant models?

Do we need to, and if so, how do we improve the accuracy of biogenic emission measurements and inventories?

If necessary how do we inventory sinks of pollutants and precursors?

How do we improve the accuracy of emission inventories in general?

V. Implementation and Control Strategies

[Concept TBD]

Issues:

What are the technical tools needed to develop integrated control strategies?

If appropriate how do we include reactivity of VOC in the control programs?

How do we demonstrate the effectiveness of control measures and strategies?

Should modeled demonstrations be required for an area to show attainment of the revised NAAQSs?

What would be a logical procedure for the "too-close-to-call" classification? This procedure is directly linked to how the standard is defined.

VI. Uncertainty

[Uncertainty: Again, this is an issue that should be separated from the topics now listed. Most of the listed topics contain mention of uncertainty, but nowhere does there appear to be an attempt to describe how the uncertainty is propagated through the system of emissions (present and future projections), air quality, meteorology and models. It is important that we understand the overall effects of the individual uncertainties on any assessments that are carried out.

How is uncertainty propagated through emissions projections, air quality, meteorology and models? Comparison of the San Joaquin Valley Air Quality Study and the Gulf of Mexico Air Quality Study have been invaluable in leading to model improvements for identifying uncertainties in the modeling results.]

Issues:

How do we handle uncertainty identified in the modeling and inventories?

How will a PM model be validated without ambient data?

What role (if any) will receptor modeling play in the PM fine implementation program?

VII. Other/Miscellaneous

How important are sinks for O3 and precursors in the system? If necessary how do we inventory sinks of pollutants and precursors?

To what extent will Title IV SOx and NOx reductions, Title I NOx RACT and the proposed PM2.5 NAAQS have an impact on regional haze?

Since the global background O3 level are increasing at a rate of 1 to 2% per year, what impact will it have on attainment of the standards?

How do we determine the O3 season, i.e., what are the spatial and temporal parameters that generate high O3 concentration days?

WORK PRODUCTS

Suggested Papers

•	Modeling - State of the Art

•	What is Meant by Ozone, Particulate Matter, and Regional Haze Integration?

•	The interface between modeling and monitoring and the differentiation between total aerosol concentrations (including ammonia nitrate, semi volitile organics and water) and the portion measured by the FRM

ADDENDUM

The following information from the North American Research Strategy on Troposheric Ozone (NARSTO) is directly pertinent to ozone-oriented issues. Indirectly, these issues will help establish a foundational format for similar relevant concerns in particulate matter and regional haze discussions. It is our hope that, upon review, we can begin to build a framework for resolving the problems peculiar to integration of ozone, particulate matter, and regional haze.

POLICY QUESTIONS FOR NARSTO 1998 ASSESSMENT

Policy question 1.

What changes have occurred in tropospheric ozone science over the last decade that might alter (or confirm) the course of current ozone air quality management strategies?

Policy question 2.

How manageable is the ozone problem for a given area? [What portion of the problem is local and what portion is transported in? What portion of the problem is essentially irreducible and what portion is potentially controllable?]

Policy question 3.

Are existing emissions control measures helping to bring the ozone problem under control? [For a given area, if these control measures are continued, will they lead to ozone attainment? What is the best role of science in developing ozone air quality management strategies?]

Policy question 4.

What are alternate approaches for reducing current and future high ozone concentrations on urban and regional scales?

Policy question 5.

How can we best track and assess the progress and effectiveness of our ozone management efforts?

Policy question 6.

Will our efforts to manage ozone help or hinder efforts to mitigate other environmental problems, such as acid rain, fine particles, and global climate change, and vice versa?

SCIENCE QUESTIONS FOR NARSTO 1998 ASSESSMENT

Science question 1.	(Addresses Policy question 1.)

What are the most significant research developments in tropospheric ozone science over the last decade?

Science question 2.	(Addresses Policy questions 2,3,4.)

How does ozone accumulation on local and regional scales depend on the source dimension and location? How does it depend on the relative contribution from local and regional sources?

Science question 3.	(Addresses Policy questions 3,5.)

What are the most recent assessments of the relative contributions of VOCs, NOx, and CO to ozone accumulation on local and regional scales in North America?

Science question 4.	(Addresses Policy questions 2,3,4.)

What are the relationships between the scientific understanding of the tropospheric ozone system and the on-going efforts to manage it?

Science question 5.	(Addresses Policy questions 3,4,5.)

What approaches are required to determine historic concentration trends of ozone and its precursors on local and regional scales? What is required to demonstrate the effectiveness of emissions control strategies over time?

Science question 6.	(Addresses Policy question 6.)

What are the relationships between the control strategies designed to manage tropospheric ozone and those designed to manage other pollutant regimes of interest?

DETAILED SCIENCE QUESTIONS FOR NARSTO 1998 ASSESSMENT

Science question 1.	(Addresses Policy question 1.)

What are the most significant research developments in tropospheric ozone science over the last decade?

o	How have these developments confirmed or changed our conceptual picture of tropospheric ozone processes?

o	What are the principal remaining scientific uncertainties?

o	Are there any scientific breakthroughs on the horizon in the next few years?

o	Would these breakthroughs/developments alter the way we are managing the ozone problem?

Science question 2.	(Addresses Policy questions 2,3,4.)

How does ozone accumulation on local and regional scales depend on the source dimension and location? How does it depend on the relative contribution from local and regional sources?

o	What are the relationships among point source, urban, regional, and larger scale processes and tropospheric ozone levels?

o	What are the regional transport influences on urban-scale ozone and the urban influences on regional tropospheric ozone?

>	How large a region must be considered; do we know how large is large enough?

>	What do modeling analyses and measurements tell us about transport scales of regional, urban, and point source emissions influences?

>	What is the sensitivity of urban ozone to regional transport of ozone, of NO2/PAN, of VOCs/carbonyls?

>	What spatial and temporal resolutions are required for modeling to assess regional transport effects on an urban area experiencing high ozone concentrations?

>	What measurements are needed, where are they needed, and what degree of accuracy is needed to assess regional transport effects on an urban area experiencing high ozone concentrations?

o	Can we better understand, further identify, isolate, and explain the fundamental physical, chemical, and meteorological processes responsible for ozone accumulation on local and regional scales?

>	What are ambient measurement programs revealing about fundamental processes?

>	What are modeling studies revealing about fundamental processes?

>	What are laboratory studies revealing about fundamental processes?

o	What is the influence of stratospheric ozone on tropospheric ozone concentrations?

Science question 3.	(Addresses Policy questions 3,5.)

What are the most recent assessments of the relative contributions of VOCs, NOx, and CO to ozone accumulation on local and regional scales in North America?

o	Is the accumulation of ozone limited by the availability of VOCs or NOx?

>	Does this limitation change from day to day for a given area or region, or from area to area on a given day, based on changes in meteorology and emissions?

>	What portion of the ozone precursors are from natural (biogenic) sources, and how will these emissions change with meteorological variability, land-use, and climate change perturbations?

Science question 4.	(Addresses Policy questions 2,3,4.)

What are the relationships between the scientific understanding of the tropospheric ozone system and the on-going efforts to manage it?

o	How do regional versus urban emissions controls affect local, urban ozone?

>	What are results of modeling analyses indicating effects of regional versus local emissions controls?

>	What measurements can be made to assess the adequacy of modeled estimates of emissions control impacts on ozone?

o	What are the critical limiting factors (uncertainties) in current models for assessing and managing urban and regional ozone problems?

>	How do strengths and limitations affect the way emissions-based air quality models are best applied?

>	Are emerging multi-scale air quality modeling systems more accurate and more useful than their predecessors in estimating regional/urban ozone, precursor, and other key species concentrations?

>	Can single (urban) scale models be used to assess regional/urban interactions?

>	What is the sensitivity of modeled ozone management strategies to the accuracies of emissions inventories?

>	What confidence do we have in model-predicted changes in ozone given a change in precursor emissions?

o	What are the critical limiting factors (uncertainties) in current measurement methods for assessing and managing urban and regional ozone problems?

>	How do strengths and limitations affect the way measurements are best used?

o	How might an efficient approach toward ozone management be constructed that combines observational analysis and modeling techniques?

>	How might such an approach be made operational?

>	What is needed for a successful modeling study in support of air quality management?

>	How can observational methods and emissions model techniques be combined to reduce uncertainty and risk? How can these risks best be communicated to decision makers?

o	What are the scientific implications of assessing ozone and strategies for its control over periods longer than an episode (up to a season or year)?

>	How will emissions control impacts change under a new primary standard, such as an 8-hr averaging period?

>	How many episodes must be analyzed to assess against the new primary standard? Is episodic modeling meaningful?

>	What new measurement and modeling methods might be required to assess a potential secondary (seasonal) ozone standard?

>	Can we characterize the seasonal ozone "baseline" or clean continental concentration for different regions?

Science question 5.	(Addresses Policy questions 3,4,5.)

What approaches are required to determine historic concentration trends of ozone and its precursors on local and regional scales? What is required to demonstrate the effectiveness of emissions control strategies over time?

o	What measurements are needed, and where, to track the impact of emissions, meteorology, ozone and precursors over time to detect a signal in each component?

o	What techniques can be applied to observed concentration trends to minimize the confounding influence of the meteorological signal?

o	What do models tell us about the confounding influence of the meteorological signal on pollutant concentration trends?

o	Since urban ozone trends are generally downward, is the basic management strategy a sound one but with need for fine-tuning, or are there more fundamental problems?

o	What do we know about ozone trends in rural areas? What is the urban ozone influence on rural concentrations?

o	What approaches are required to evaluate ozone exposures of humans and ecosystems?

o	How can measurements be best utilized?

>	What are the most important additions/improvements in PAMS and similar monitoring to facilitate emissions inventory evaluation and improvement, air quality model evaluation and improvement?

>	What types of method development efforts, field studies, and training are needed to maintain high quality data from PAMS and similar networks?

>	What data analysis techniques are most useful, for scientific or regulatory purposes, in eliciting information from the PAMS and similar data?

>	How can the long-term sustained effort in PAMS or other monitoring be used to establish progress in achieving improved air quality?

>	What improvements are needed in the long-term monitoring effort in rural areas?

Science question 6.	(Addresses Policy question 6.)

What are the relationships between the control strategies designed to manage tropospheric ozone and those designed to manage other pollutant regimes of interest?

o
What are the linkages and feedbacks between other pollutants of concern (especially, fine particles, regional haze, acid deposition, and airborne toxics) and tropospheric ozone?

o	Can future operational assessments be performed in an integrated manner across different pollutant regimes?