Causes of Haze (COHA)
Scope of Work
This page outlines the tasks that will be completed by DRI
and its’ subcontractors for the initial phase of the Causes of Haze Contract.
Completion of these tasks is necessary to answer the causes of haze questions
listed in the RFP and will provide either some of all of the information needed
to answer each sub-question. More detailed information regarding the technical
approach appears in our original proposal titled “Causes of Haze in the Western
United States” (June 11, 2002) and the revisions given in our response to the
request for clarification of our proposal (titled “DRI Clarification to WRAP
Causes of Haze Proposal”, dated August 5, 2002).
A matrix of the analysis methods proposed for the study (some only in later
study phases) and the questions addressed by each analysis method in shown in
Task 1: Emissions density maps (supports questions 3a., 3b.,3c., 3e.,
Gather emissions data and prepare emissions density maps for the WRAP region and
nearby areas in Canada and Mexico for SO2, NOX, NH3, PM2.5, PM10, organic
carbon, and elemental carbon for the WRAP region and nearby areas in Mexico and
Canada. Locations of large point sources and urban areas will be noted.
These will be used to:
- Help in interpreting the aerosol component data;
- Determine relationship of sources to the Class I areas;
- Interpreting results of backtrajectory analysis;
- To examine relationships between mesoscale meteorological transport and
efforts of the sources upon Class I areas (next phase of study)
Task 2: Monitoring site setting description (supports question 1c.)
Describe the IMPROVE/IMPROVE protocol monitoring sites representing Class I
areas in regards to:
- Their representation of the Class I area and nearby Class I areas;
- Relationship to terrain features, bodies of water, etc.;
- Proximity to major point sources, cities, etc. Information from the emissions
compilation described above will be quite useful.
Task 3: Meteorological setting of monitoring sites (supports question
Assess the meteorological setting of the sites with respect to:
- Expected mesoscale flow patterns of interest (sea/land breeze, mountain/valley
winds, convergence zones,etc.);
- Orographic precipitation patterns (i.e. favored for precipitation, or in
- Inversion layers;
- Potential for transport from cities and other significant sources/source
A more detailed assessment will be done in the second phase of the study.
Task 4: Aerosol data analysis (supports questions 1a., 1b., 1c., 1d.,
- Gather aerosol data for all sites in the WRAP region
- Prepare descriptive statistics and interpretation for the aerosol data for all
sites with monitoring data;
individual components as well as reconstructed extinction will be included;
- Document and interpret the spatial and seasonal patterns for aerosol
- Determine best 20%, middle 60%, and worst 20% reconstructed extinction days
and their seasonal patterns at each site;
- Compile and describe spatial and seasonal patterns of aerosol components
- Interprete aerosol component data in light of the emissions sources and
monitoring site settings analyses from the previous tasks and the backtrajectory
analyses described in the next task.
- Use cluster analysis to group sites having similar patterns in aerosol
component contributions to haze.
Task 5: Backtrajectory analysis (supports questions 2a., 2c., 2e., 3a.)
- Gather backtrajectory endpoint data
- Compute and map backtrajectory summary statistics including residence time by
season, and best 20% and worst 20% reconstructed extinction and aerosol
components for all sites with 5 years or more of data.
- Prepare conditional probability maps for high and low extinction and aerosol
- Interpret the maps using emissions density and location information, and site
setting information obtained from tasks listed earlier.
Task 6: Conceptual model development (supports overall goal of
determining causes of haze)
- Develop preliminary conceptual models regarding the sources of haze at every
Class I area in the WRAP region;
- Note uncertainties and limitations of the conceptual models;
- Suggest methodologies to refine the conceptual models in the next phase of the
Task 7: Reporting
- Make all the information gathered available over the Internet in the form of a
- Coordinate closely with appropriate WRAP participants and the WRAP project
The deliverable is a virtual report available over the Internet containing the
information described in the above tasks. Progress made toward answering each
Cause of Haze question and the uncertainty or remaining work to be done to
address the questions will be described.