A Pilot Program for Streamlining Particulate Matter (PM) and Mobile Source Air Toxics (MSATs) Project-Level Air Quality Analyses with Programmatic Agreements (PAs).

Focus Area

Air Quality


Air Quality






Under 1 year

Research Idea Scope

Most recently, NCHRP 25-25 Task 78, developed templates for a PA for CO hot-spot analysis and identified needed research areas to develop PAs for PM hot spot analyses and MSAT analyses. This proposed research flows directly from those identified research areas. By way of background, PM project-level hot-spot analyses and MSAT analyses are undertaken to satisfy various environmental requirements (e.g. NEPA, state environmental laws). Different modeling approaches have been developed and used to determine whether a transportation project has the potential to violate a PM ambient air quality standard or the potential to results in unacceptable emissions of MSATs. Federal guidance has been developed to evaluate potential impacts of transportation projects on levels of these pollutants. FHWA has Interim Guidance on Air Toxics Analysis in NEPA Documents (http://www.fhwa.dot.gov/environment/air_quality/air_toxics/policy_and_guidance/aqintguidmem.cfm) and USEPA has Transportation Conformity Guidance for Quantitative Hot-spot Analyses in PM2.5 and PM10 Nonattainment and Maintenance Areas (http://www.epa.gov/otaq/stateresources/transconf/projectlevel-hotspot.htm). The PM guidance was developed for use in project-level conformity determinations in these nonattainment and maintenance areas. However, many practitioners at the state DOT level use this guidance as available technical support for other purposes than project-level conformity determinations (e.g. NEPA or state environmental review analyses). Since this guidance is being used in a non-regulatory setting, opportunities exist for flexibility and for streamlining the analysis steps in this guidance. The proposed research relies on the experience gained over the last several years doing PM hot-spot analysis and MSAT analyses for transportation projects. It would most directly build upon the work of NCHRP 25-25, Task 78. The proposed research would utilize and build upon the research areas identified in Task 78 for the development of PAs for PM and MSAT analyses and apply them to a state DOT to develop and implement a PA for these pollutants. It would start at the beginning of the process and continue through necessary approvals and subsequent implementation at the state DOT. The Tasks for this proposed research would be developed in consultation with the state DOT that would best meet their needs, but in general, would likely consist of Tasks as outlined below, generally following the USEPA PM Hot-spot guidance: 1. Ascertain from state DOT issues, past procedures, needs, etc. related to PM hot-spot and MSAT analyses in their state. 2. Determine Need for Analysis. The need for an analysis is based on whether a project is similar to a project of local air quality concern. A PA could include elements that identify facilities for which highway projects would not need a PM hot-spot analysis because they are not at locations that have high volumes, have congested intersections or high levels of truck traffic. 3. Determine Approach, Models and Data. This Step offers opportunities for streamlining the hot-spot analysis and establishing elements of a PA. These include: – Establish an overall approach to the analysis, perhaps by project type. This could include: scale and scope of the analysis (i.e. the “project area”); build and no-build analysis; emission sources to be modeled; applicable PM NAAQS to be evaluated; applicable models by project type; use of project-specific or state-specific data; sources of meteorological data; agency coordination and schedule considerations; determination of analysis years (year of maximum emissions or multiple years); sources of PM emissions to be modeled such as: exhaust emissions, running losses emissions, crankcase emissions, brake and tire wear emissions, and road dust emissions ( for PM10, perhaps for PM2.5); construction emissions; year round or peak season analysis. 4. Estimate On-Road Motor Vehicle Emissions. The inputs for MOVES can be determined at this point and be included as part of a PA. 5. Estimate Emissions from Road Dust, Construction and Additional Sources. This Step offers a substantial number of opportunities to incorporate streamlined aspects of a hot-spot analysis and to insert elements into a PA. These include: – Determine whether there is a need to include nearby emission sources in the hot-spot analysis. – Determine the need to include re-entrained road dust for a PM2.5 hot spot analysis. It is expected that in most cases, road dust will not need to be included. – Establish the methodology for estimating road dust for a PM10 hot-spot analysis. – Determine whether there is a need to include construction emissions. It is expected that in most case, construction emissions will not be included. – Establish a methodology or agreement for obtaining data for nearby emission sources. 6. Select Air Quality Model, Data Inputs and Receptors. This Step also offers opportunities for project analysis streamlining and development of elements of a PA. These include: – Determine which project types will use CAL3QHC/R as the dispersion model and which project types will use AERMOD as the dispersion model. – When AERMOD is to be used, establish under which circumstances, if any, the volume, area or point source modes will be used. – Determine which meteorological inputs will be assumed “worst-case” and which will be based on measured data. – For “worst-case” inputs, establish the values to be used. – For measured data, establish source of the data, data completeness and adequacy and data recentness requirements. – Establish source of traffic inputs (i.e. micro-simulation models, observed and forecasted values, etc.) – Describe time units of inputs to arrive at appropriate units of the applicable ambient air quality standard (e.g. hourly traffic volumes leading to a comparison of the annual or daily PM2.5 air quality standard). – Establish land use and surface characteristics, by locations across the state. – Determine selection and placement of receptors, based on pollutant analyzed. – Establish inappropriate locations for receptors (e.g. in highway ROW, downwind of a specific stationary source). 7. Determine Background Concentrations. This Step offers opportunity for streamlining a hot-spot analysis or determining the elements of a PA, all related to background concentration. These include: – Determine if nearby sources should be considered in establishing background levels. – If needed, establish process for calculating nearby sources contribution to background levels and how they will be calculated for future years. – Examine location and operation of air monitoring stations for applicable pollutants and obtain data. – Develop procedure for determining appropriate monitoring locations to areas of the State in which projects may be located. – Establish which areas of the State will use a single monitor to determine background. – Establish which areas of the State will use multiple monitors to determine background and develop interpolation scheme among monitors. – Develop process for adjusting background levels to account for future changes in air quality (use of chemical transport model and/or on-road emissions model). 8. Calculate Design Value and Determine Air Quality Impact. The USEPA guidance labels this Step as “Calculate Design Value and Determine Conformity”. Because this is related to PAs as part of a NEPA or state environmental required analysis undertaken in an attainment area, conformity does not apply and therefore, conformity would not be determined. However, it would be necessary to determine if the project causes a significant adverse air quality impact. That could done as part of a PA. The PA could establish: – What constitutes a significant adverse impact. – The availability of a “de minimus” impact, i.e. a small incremental increase in pollutant levels above the No-Build alternative that would not be considered a significant adverse impact. The “de minimus” concept recognizes the inherent uncertainty in the data inputs and model formulations and allows for a minimal pollutant addition from the project to pollutant levels from other sources and background levels. The background levels determined in Task 7 would be used to calculate the design value. For PM analyses, the PA could establish the process for calculating the design value and which tier and sequence of tiered analysis would apply for the daily PM2.5 standard. The PA could also determine under what circumstances, if any, alternate methods of calculating a design value could be considered. The PA could also establish what locations may be considered “unique” and, therefore, not appropriate for consideration of the annual PM2.5 standard in determining a significant adverse air quality impact. 9. Consider Mitigation or Control Measures. If a project results in a significant adverse impact, as defined in the PA (see Task 8 above), mitigation to reduce or eliminate the impact could be considered. The PA could address mitigation through a general policy approach that defines the goal of the mitigation (e.g. “to reduce or eliminate the significant adverse air quality impact to the maximum extent practicable”) or identify specific mitigation or control measures, perhaps by project type. For example, this could include turn lanes or separated lanes or relocated stop lines for intersection or highway projects, or reduced idle time for busses for transit projects. The PA could also explore the concept of “emissions credit” in which the project sponsor agrees to reduce emissions from another source with those emission reductions to be credited as mitigation for the project. The PA would also establish the point at which mitigation is sufficiently successful and the point at which further mitigation efforts would not be practicable or successful. 10. Document the Analysis. The PA could establish a template for project and analysis documentation with gaps to be filled in with project specific information or colored text to indicate where project information could be inserted. Alternatively, the PA could establish a list of parameters that should be included in the project and analysis documentation. For example, this could include a brief description of the project, the models used in the analysis, the results of the analysis, etc. 11. Assist state DOT with PA approvals and implementation, as needed 12. Develop Final Report documenting issues and obstacles encountered and solutions used to finalize the PA.

Urgency and Payoff

With few, if any, state DOTs having state-specific PAs for these pollutants (other than procedures referring to the Federal guidance), this proposed research would build upon the work of Task 78 and develop and implement a state-specific PM hot-spot and/or MSAT PA in one state. Information from this research could then be used to inform the process for PA development and implementation for other state DOTs. This would benefit other state DOTs that wish to develop a PAs for these pollutants for their state by identifying procedural, administrative or technical challenges and potential solutions which then could be applied by the other state DOTs. Research is needed to identify and address challenges, both technical and procedural, with development and implementation of PAs to be used by state DOTs to determine and document under what project types and conditions (e.g. road grade, number of lanes) a project-level PM hot-spot analysis or MSAT analysis would not be needed. The research would encompass the entire process of PA development and implementation, from start through needed approvals and implementation. The outcome would be a completed and implemented PA for these pollutants in one state. Lessons learned from this research. Upon successful completion of the proposed research, similar work could be performed for any state DOT that would benefit from having a state-specific PA in place for PM hot-spot and MSAT analysis. It is envisioned that most state DOTs would realize an improvement in their environmental process by clarifying and simplifying the requirements and assumptions in undertaking an analysis for these pollutants.

Suggested By

John Zamurs ZAMURS AND ASSOCIATES, LLC 5184563545

[email protected]