Presentation on theme: "EPA 40 CFR Part 51, Appendix W Rural-Urban Classification"— Presentation transcript:
1A Land Use Tool for AERMOD Urban/Rural Classification John Glass South Carolina – BAQ
2EPA 40 CFR Part 51, Appendix W Rural-Urban Classification Section 7.2.3:c. Land Use Procedure:(1) Classify the land use within the total area, Ao, circumscribed by a 3km radius circle about the source using the meteorological land use typing scheme proposed by Auer 73;(2) if land use types I1, I2, C1, R2, and R3 account for 50 percent or more of Ao, use urban dispersion coefficients; otherwise, use appropriate rural dispersion coefficients.d. Population Density Procedure:(1) Compute the average population density, p per square kilometer with Ao as defined above;(2) If p is greater than 750 people/km2, use urban dispersion coefficients; otherwise use appropriate rural dispersion coefficients.e. Of the two methods, the land use procedure is considered more definitive.Basis for urban/rural determination
3SC-BAQ before 2008 AQ modeling guidelines (2001): ”With few exceptions, all of SC is considered to be rural. Typically, the areas in the large metropolitan areas of the state (Greenville/Spartanburg, Columbia, and Charleston) will meet one of the … definitions of urban.”►Limited population-based checking by SC-BAQ for facilities claiming “Urban” near metro “cores”
4SC-BAQ starting in 2008 Objective “Urban-Rural” Tool Based on preferred LAND USE methodUses GIS/ArcView“Bridge” from Auer’s scheme to NLCD 2001
5Auer vs. NLCD 2001 Auer – “Urban” NLCD 2001 <5 % 0-20 % 24 20-50 % TypeUseVegetationPerviousNo.I1Heavy Industrial<5 %0-20 %Dvlpd, hi intensity24I2Light Industrial20-50 %Dvlpd, med intensity23C1Comm.<15 %50-80 %Dvlpd, low intensity22R2Compact Residential<30 %R3<35 %Use only NLCD classes 23 & 24 for “Urban.” Roughly equate %pervious to %vegegation.
6User’s Basic Steps 1. Open “Land Use” tool in ArcView 2. Enter Lat/Lon of facility3. Create buffer (circle) at r=3 km4. Activate % land use algorithm5. Sum % for NLCD categories 23 & 24(≥50%=URBAN, <50%=RURAL)
7Example: Downtown Columbia Constructed with the ArcGIS model builder using the buffer tool and spatial analysis tool.
8Results - % Land Use Algorithm 50%"Urban"Results export to Access database
9Compare 2 downtown locn’s Before20082008+North(yellow)Urban?Rural(46%)South(black)Urban(50%)Locations are ~half mile apart. B4 land-use tool, SC-BAQ likely would’ve accepted urban AERMOD run for both locations (limited checking, and near “core” of Columbia) . Now, land-use tool suggests northern locn is “rural.”