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March 11, 1998 NRE 501 Robin Saha

Preliminary Steps toward Developing a Sound Research Design for Analyzing the Spatial Distribution of Commercial Hazardous Waste Facilities in Wayne County, Michigan: Part I. March 11, 1998 NRE 501 Robin Saha. General Research Question.

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March 11, 1998 NRE 501 Robin Saha

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  1. Preliminary Steps toward Developing a Sound Research Design for Analyzing the Spatial Distribution of Commercial Hazardous Waste Facilities in Wayne County, Michigan: Part I March 11, 1998 NRE 501 Robin Saha

  2. General Research Question Are low income and minority populations disproportionately exposed to the risks associated with commercial hazardous waste facilities in Wayne County, Michigan?

  3. Research Design Issues • Defining geographic areas of impact (“impact zones” or “ host neighborhoods”) • Selecting a geographic unit of analysis (census tracts versus block groups)

  4. Location of Wayne County, Michigan

  5. STUDY AREA AND TSDF LOCATIONSWayne County, Michigan

  6. Considerations in Defining Impact Zones (Design Issue #1) • Proximity of known or potential impacts • Inverse relationship between distance and impact (social, psychological, economic, environmental, and health ) • Size and shape of geographic units for which demographic data are available • Previous research and comparability with other studies

  7. DESIGN ISSUE #2Considerations in Selecting an Appropriate Unit of Analysis • How different units affect the delineation of host neighborhoods in terms of how well they approximate circular areas • Want to create host neighborhoods (“impact zones”) that are as equivalent as possible in size and shape (equidistant from hazardous waste facilities) -- inter-case consistency

  8. Census Tracts with TSDFs

  9. Census Tracts at Least Partially within 1/2 Mile Circle Centered at TSDFs

  10. Census Tracts at Least Partially within 1.0 Mile Circle Centered at TSDFs

  11. 1990 Census Tracts Partially within 1.5 Mile Circle Centered at TSDFs

  12. 1990 Census Tracts at least Half within 1.5 Mile Circle Centered at TSDFs

  13. Number of Census Tracts Partially within and at Least Half within 1.5 Mile Radius of TSDFs

  14. Area in Decimal Degrees of Census Tracts Partially within and at Least Half within 1.5 Mile Radius of TSDFs

  15. Area of Census Tracts Partially within and at Least Half within 1.5 Mile Radius of TSDFs, as a Percentage of Wayne County

  16. Delineation of Host Neighborhood as Census Tracts Partially Encompassed by Circle of 1.0 Mile Radius #

  17. Delineation of Host Neighborhood as Census Tracts with Area at Least Half within Circle of 1.0 Mile Radius #

  18. Census Tracts Partially within 1.5 Mile Circle Centered at Env’l Waste Control

  19. Census Tract at Least Half within 1.5 Mile Circle Centered at Env’l Waste Control

  20. Block Groups Partially within 1.5 Mile Circle Centered at Env’l Waste Control

  21. Block Groups At Least Half within 1.5 Mile Circle Centered at Env’l Waste Control

  22. Census Tracts Partially within 1.5 Mile Circle Centered at ChemMet

  23. Block Groups Partially within 1.5 Mile Circle Centered at ChemMet

  24. Census Tracts At Least Half within 1.5 Mile Circle Centered at ChemMet

  25. Block Groups At Least Half within 1.5 Mile Circle Centered at ChemMet

  26. Census Tracts within 1.5 Miles of City Environmental Facility X

  27. Block Groups within 1.5 Miles of City Environmental Facility X

  28. “Underlap” and Overlap of Census Tracts within 1.5 Miles of City Environmental X

  29. “Underlap” and Overlap of Block Groups within 1.5 Miles of City Environmental X

  30. Area As a Percentage of 1.5 Mile Circle of Underlap and Overlap for City Environmental

  31. Comparison of Host Neighborhood Delineations Using Census Tracts and Block Groups

  32. Total Population in Host Neighborhoods Using Tracts vs. Combination of Tracts and Block Groups

  33. Selected Demographics of Host Neighborhoods Using Tracts vs. Combination of Tracts and Block Groups

  34. Conclusions Regarding Host Neighborhood Delineations • Areas within a given radius delineate significantly different host neighborhoods using partially vs. mostly circumscribed geographic units (tracts or block groups) • Host neighborhood shape and size can (but do not always) vary significantly depending on whether tracts or block groups are used and urban vs. non-urban locations • Tract/block group differences appear to be insignificant for highly urbanized locations (based on City Env’l TSDF) • Need to repeat analysis for other host neighborhoods, especially for suburban and rural locations

  35. Conclusions Regarding Units of Analysis • Preliminary findings suggest choice of using census tracts or block groups can significantly influence demographic results • These differences need be more carefully assessed before research design decisions regarding most appropriate unit of analysis can be made • Methods for estimating demographic data in “underlap” and overlap areas may address both research design issues

  36. THE END

  37. STUDY AREA AND TSDF LOCATIONSWayne County, Michigan

  38. Area in Square Miles of Underlap and Overlap for City Environmental

  39. Census Tracts at Least Partially within 2.0 Mile Circle Centered at TSDFs

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