1. A Land Use Tool for AERMOD Urban/Rural Classification John Glass South Carolina – BAQ

2. EPA 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

3. SC-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”

4. SC-BAQ starting in 2008 Objective “Urban-Rural” Tool
Based on preferred LAND USE method
Uses GIS/ArcView
“Bridge” from Auer’s scheme to NLCD 2001

5. Auer vs. NLCD 2001 Auer – “Urban” NLCD 2001 <5 % 0-20 % 24 20-50 %
Type
Use
Vegetation
Pervious
No. I1
Heavy Industrial
<5 %
0-20 %
Dvlpd, hi intensity 24 I2
Light Industrial
20-50 %
Dvlpd, med intensity 23 C1
Comm.
<15 %
50-80 %
Dvlpd, low intensity 22 R2
Compact Residential
<30 % R3
<35 %
Use only NLCD classes 23 & 24 for “Urban.” Roughly equate %pervious to %vegegation.

6. User’s Basic Steps 1. Open “Land Use” tool in ArcView
2. Enter Lat/Lon of facility
3. Create buffer (circle) at r=3 km
4. Activate % land use algorithm
5. Sum % for NLCD categories 23 & 24
(≥50%=URBAN, <50%=RURAL)

7. Example: Downtown Columbia
Constructed with the ArcGIS model builder using the buffer tool and spatial analysis tool.

8. Results - % Land Use Algorithm
50%
"Urban"
Results export to Access database

9. Compare 2 downtown locn’s
Before
2008
2008+
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.”

10. John Glass, 803-898-4074, glassjp@dhec.sc.gov
COMMENTS ??
QUESTIONS ??
John Glass, ,