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Strategic Workplan for Air Toxics Research

5: Conclusions

Figure 3 summarizes the priority research recommendations from the May 12, 2003 workshop. This diagram is the blueprint for the workplan, and it identifies how each priority project helps to answer one or more of the transportation community's critical policy questions. Research to help understand the contribution of transportation sources to air toxics is emphasized because this is a critical need. The blueprint shows how the research priorities in this plan seek to answer the transportation community's critical research questions.

FHWA acknowledges that the technical complexity and broad scope of the projects contained in the workplan will require a coordinated, multi-agency approach. The multi-disciplinary range of projects outlined in Figure 3 will likely require coordination among FHWA, State Departments of Transportation, and metropolitan planning organizations, as well as involvement by academic and applied research organizations as well as State and Federal air quality agencies, and industry groups. Dialogue among all these groups is encouraged to facilitate speedy resolution of issues critical to implementing this workplan, particularly, equitable distribution of research leadership, development of detailed project scope information, and funding responsibilities for individual projects.

Figure 4 displays information about the expected staging of the research initiatives and related sub-areas and their relationships to each other. For each programmatic initiative, the timing is identified as either early, intermediate, or late to indicate the possible relative ordering with which this research might be pursued. For each programmatic initiative, Figure 4 also lists the related research areas. This indicates situations where one programmatic initiative intersects with others. Similarly, Figure 4 also indicates where a programmatic initiative, or a sub-area, is expected to be informed by research efforts that would be expected to be performed at an earlier stage in the research process.

Workshop

Sessions:

Characterization

Ambient Monitoring

Analysis

Control Measures/Strategies

 

P1: Fund research for improvements in emission measurement technology that are needed to measure the lower emission levels of air toxic compounds expected with improved emission control technologies and lower sulfur fuels expected in the 2005 to 2007 time frame.

P4: Fund research to identify what additional monitoring information needs to be collected to enhance existing monitoring networks to meet transportation sector needs.

P7: Develop a protocol on the appropriate methods to be used in emissions modeling, atmospheric dispersion modeling, and exposure modeling at varying spatial scales applicable to transportation projects (e.g., project-level, urban scale).

P11: Performing studies of potential control measures and their cost effectiveness is predicated on there being observed harmful levels which can be ameliorated by reducing motor vehicle emissions. Therefore, any programmatic initiatives to reduce air toxic emissions need to be informed by research on existing ambient air toxic concentrations, estimated associated risks, and the mobile source contributions to them.

 

P2: Design and initiate experiments to examine near roadway concentration patterns (especially for highways). There is evidence that air toxic concentrations near roadways are appreciably higher than those 300 to 500 meters or more downwind. Experiments to examine these gradients are likely to assist in steering future research toward examining pollutant emissions, fate, and transport.

P5: Fund research to understand existing, and develop new, practical tools for local and regional organizations to assess MSAT impacts and evaluate results.

P8: Conduct research and develop methods on variability and uncertainty analysis of on-road emission estimates. Identification of key sources of uncertainty can be used to target resources to reduce uncertainty.

Sub-Area 1: Research the expected multi-media MSAT benefits or dis-benefits of the control measures that are expected to be the leading candidates for adoption in upcoming 8-hour ozone and PM2.5 nonattainment plans.

 

P3: Conduct research to expand the available set of information about air toxic emissions and activity patterns for the on-road and off-road vehicle types with the most significant contributions to ambient air toxic concentrations of concern and the greatest uncertainty in their emission estimates. Two sub areas within this programmatic initiative have been identified as likely first priorities for study.

P6: Determine whether the existing knowledge about transportation air toxics can be enhanced by further examining current data.

P9: Develop improved inputs for emissions and receptor modeling. Some improvements are expected via incorporating already available data. Gap filling research may be needed in selected topics.

Sub-Area 2: Determine the emissions and potential emission reductions for measures that could be applied to mitigate the emissions from non-road construction equipment that is typically used in constructing/widening highways.

 

Sub-Area 1: There are needs to investigate the differences in fleet populations and travel characteristics for important sub-categories of trucks. These sub-categories can be defined as: long-range fleet, regional fleet (300 to 500 miles), and local fleet (primarily delivery trucks).

 

P10: Research the atmospheric chemistry of mobile source air toxics. Incorporate this information into distributed modeling tools. This area could be considered a sub-area of P7 above.

Sub-Area 3: Research the effectiveness of control strategies on toxics. This initiative specifically focuses on identifying the most cost effective control strategies available for reducing air toxic emissions. What would provide the best and most cost effective results where the most cost effective air toxics control strategies could differ from the most cost effective criteria pollutant options?

 

Sub-Area 2: For off-road engines/vehicles, diesel-powered construction equipment is a major emissions source (of PM) with large uncertainties in emission estimates.

     

Figure 3. Priority Mobile Source Air Toxic Research Areas

Characterization
Ambient Monitoring
Analysis
Control Measures/Strategies
P1: Measurement Technology Improvements
P4: Network Enhancements
P7: Modeling Protocols
P11: Where Needed?
Timing: Early
Timing: Early or Intermediate
Timing: Early
Timing: Early
Related Research: N/A
Related Research: P1
Related Research: N/A
Related Research: P3
Informed by: N/A
Informed by: N/A
Informed by: P10
Informed by: N/A
P2: Near Roadway Experiments
P5: Tools for State and Local Agencies
P8: Uncertainty Analysis
Sub-Area 1: SIP Related Benefits
Timing: Early
Timing: Early
Timing: Intermediate
Timing: Intermediate
Related Research: P7 and P10
Related Research: N/A
Related Research: N/A
Related Research: N/A
Informed by: N/A
Informed by: P2
Informed by: N/A
Informed by: P11
P3: Emissions/Activity Patterns by Vehicle Type
P6: Data Analysis
P9: Improved Model Inputs
Sub-Area 2: Non-Road Measures
Timing: Early
Timing: Early or Intermediate
Timing: Intermediate
Timing: Late
Related Research: P8 and P11
Related Research: P11
Related Research: N/A
Related Research: P3
Informed by: N/A
Informed by: N/A
Informed by: All
Informed by: P11
Sub-Area 1: Trucks
 
P10: Research Air Chemistry
Sub-Area 3: Focused Air Toxic Measures
Timing: Intermediate
 
Timing: Early
Timing: Late
Related Research: N/A
 
Related Research: P2
Related Research: N/A
Informed by: P2 and P11
 
Informed by: N/A
Informed by: P11
Sub-Area 2: Diesel Construction Equipment
     
Timing: Late
     
Related Research: P11 Sub-Area 2
     
Informed by: P11 and P2
     

Figure 4. Research Area Relationships and Timing

Updated: 07/06/2011
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