APPENDIX E 

Surface Characteristics Representativeness Analysis 
Protocol to Support the use of Airport Meteorological Data 

For Sanders Lead Modeling 

One of the more important inputs to an air quality dispersion model is the meteorological 

data. The meteorological data will dictate where emitted compounds will be transported 

based on information such as wind speed, wind direction, ambient temperature, and 

atmospheric surface boundary layer parameters which help define atmospheric stability 

and mixing height development. The more meaningful the meteorological inputs, the 

greater the likelihood of useful results. 

Recognizing that not all locations have access to meteorological data, EPA developed 

methods whereby data obtained not at the site, but from another locale, could be used if 

shown to be reasonably representative of conditions at the modeling site. 

This test of representativeness has been described in EPA guidance (Guideline on Air 

Quality Models) (40 CFR 51 Appendix W) and AERMOD/AERMET implementation 

guidance, including the most recent version issued March 19, 2009. The test of 

representativeness was originally intended in the Guideline on Air Quality Models to 

include both a spatial and temporal component together with a suitability component. In 

the EPA Meteorological Monitoring Guidance for Regulatory Modeling Applications, 

representativeness has been defined as "the extent to which a set of measurements taken in 

a space-time domain reflects the actual conditions in the same or different space-time 

domain taken on a scale appropriate for a specific application." 

The meteorological monitoring guidance continues to say that " ... for use in air quality 

modeling applications, meteorological data should be representative of conditions 

affecting the transport and dispersion of pollutants in the area of interest as determined by 

the locations of the sources and receptors being modeled." Establishing representativeness 

balances the requirements of the modeling assessment with the reasonableness of 

meteorological data acquisition. 

Because ADEM modeling guidance recommends meteorological data from the 

Montgomery Airport for sources located in Pike County, Alabama, it is assumed the data 

has previously undergone a "representativeness" review by ADEM. This ADEM review 

may have included a review of many similarities between a source located in a modeled 

county and the nearby airport. The similarities tests would have included potential effects 

of terrain on regional flow patterns between the two sites and changes in climatology 

between the two areas. Because the Sanders Lead facility and Airport are both located in 

an area of relatively simple terrain, no major changes in regional air flow would be 

expected. Also, since the Airport and plant site are both located in the East Gulf Coastal 

Plain region, only small changes in climatology and other weather related factors would 

be expected therefore the space-time domain factors should be representative. Localized 

differences in some surface boundary layer parameters (i.e., albedo, Bowen ratio, and 

surface roughness) between the two sites would be expected but not to a degree that would 

exceed changes in predicted concentrations often noted from just using different years of 

meteorological data. 
Based on the presumed suitability of the meteorological data for sources located near the 

Montgomery Regional Airport, the ADEM processed the data using AERMET (version 

06341) along with upper air data from Alabaster, Alabama, to form a 5-year 

meteorological record (2001-2005). The data was processed using geophysical surface 

parameters associated with the airport. This information was developed by using the 

AERSURF ACE program which generates surface boundary layer parameters in the form 

of albedo, Bowen ratio, and surface roughness. 

For this protocol, Sanders Lead duplicated the AERMET processing for one year (2005) 

but used boundary layer parameters generated by AERSURFACE based on land use 

patterns around the facility. 

The first quarter or first three months, of 2005 were modeled in AERMOD using the two 

meteorological data sets to understand the relative importance of the chances in 

AERSURFACE processing to predicted ambient concentrations. For this analysis, only 

point sources were evaluated. Emission rates used in this initial evaluation were based on 

current allowable emission estimates. These may or may not be a good estimate of 

"actual" potential emission rates from the facility. Actual emissions rates are under 

review, at this time. Using the allowable rates supplied a basis for conducting the 

modeling only. No actual concentration estimates are reported. Results are presented on 

a "relative" basis in the form of concentration isopleths. 

The initial modeling results indicate there would be about a 22 percent change in 

predicted concentrations using the different data sets. However, the location of maximum 

impact remains the same. The meteorological data with "site" geophysical surface 

parameters causes the higher predicted concentrations. This is understandable given the 

large changes in surface roughness between the airport and the plant site (see Table 1 and 

Figures 1 thru 4). It would be expected that elevated plumes would experience greater 

instability with greater surface roughness and therefore cause higher impacts near the 

plant site. Figure 5 displays the location of maximum impacts for the 1st quarter of 2005. 

Both datasets produce highest values at the fence line and at the same receptor location. 

Table 1 compares the differences in the boundary layer parameters at the airport and plant 

site. The information has been broken down into 12 sectors and 4 seasons. 

A strong indication of the representativeness of data collected at the airport for modeling 

the plant site is the relatively small change in predicted impacts from the AERMOD 

model using the two meteorological data sets. The airport data is considered 

"representative" since the location of maximum impacts are the same and a 22 percent 

change in predicted concentrations would be a reasonable variation frequently seen in year 

to year variation over long-term averaging periods when modeling. 

As recommended by the ADEM, both AERSURFACE data sets will be used for future 

modeling and the data set producing the highest predicted concentrations will be reported. 

This is a conservative modeling assumption. 
Table 1 

AERSURFACE 

Processing Bowen Bowen Surface Surface 

Surface Albedo Albedo Ratio Ratio Roughness Roughness 

Geophysical Season Airport Sanders Airport Sanders Airport Sanders 

Lead Lead Lead 

Parameters Sector 

1 1 0.17 0.15 0.71 0.81 0.095 0.256 

2 I 0.17 0.15 0.71 0.81 0.055 0.322 

3 I 0.17 0.15 0.71 0.81 0.031 0.238 

4 I 0.17 0.15 0.71 0.81 0.019 0.445 

5 I 0.17 0.15 0.71 0.81 0.019 0.508 

6 1 0.17 0.15 0.71 0.81 0.041 0.186 

7 I O.I7 O.I5 0.7I 0.81 0.02I O.I58 

8 I O.I7 0.15 0.7I 0.8I O.OI8 0.201 

9 I O.I7 O.I5 0.7I 0.81 0.015 0.503 

IO I 0.17 O.I5 0.7I 0.81 0.024 0.532 

11 I 0.17 0.15 0.71 0.8I 0.039 0.199 

I2 I 0.17 O.I5 0.7I 0.81 0.07I 0.139 

I 2 0.17 0.15 0.71 0.81 0.095 0.256 

2 2 0.17 0.15 0.71 0.81 0.055 0.322 

3 2 0.17 0.15 0.7I 0.8I 0.031 0.238 

4 2 0.17 0.15 0.71 0.8I O.OI9 0.445 

5 2 0.17 O.I5 0.7I 0.81 0.019 0.508 

6 2 0.17 O.I5 0.7I 0.81 0.04I 0.186 

7 2 O.I7 0.15 0.7I 0.8I 0.02I 0.158 

8 2 O.I7 O.I5 0.71 0.81 0.018 0.201 

9 2 0.17 0.15 0.71 0.81 0.015 0.503 

10 2 0.17 0.15 0.71 0.81 0.024 0.532 

11 2 0.17 0.15 0.71 0.8I 0.039 0.199 

12 2 0.17 0.15 0.7I 0.8I 0.07I O.I39 

1 3 O.I4 O.I4 0.38 0.56 0.1I4 0.324 

2 3 0.14 0.14 0.38 0.56 0.066 0.404 

3 3 0.14 0.14 0.38 0.56 0.038 0.271 

4 3 O.I4 0.14 0.38 0.56 0.026 0.543 

5 3 0.14 0.14 0.38 0.56 0.028 0.635 

6 3 0.14 0.14 0.38 0.56 0.050 0.238 

7 3 0.14 0.14 0.38 0.56 0.030 0.192 

8 3 O.I4 O.I4 0.38 0.56 0.027 0.248 

9 3 0.14 0.14 0.38 0.56 0.022 0.592 
AERSURFACE 

Processing Bowen Bowen Surface Surface 

Surface Albedo Albedo Ratio Ratio Roughness Roughness 

Geophysical Season Airport Sanders Airport Sanders Airport Sanders 

Lead Lead Lead 

Parameters Sector 

10 3 0.14 0.14 0.38 0.56 0.032 0.626 

11 3 0.14 0.14 0.38 0.56 0.050 0.255 

12 3 0.14 0.14 0.38 0.56 0.090 0.170 

1 4 0.14 0.14 0.38 0.56 0.114 0.324 

2 4 0.14 0.14 0.38 0.56 0.066 0.404 

3 4 0.14 0.14 0.38 0.56 O.D38 0.271 

4 4 0.14 0.14 0.38 0.56 0.026 0.543 

5 4 0.14 0.14 0.38 0.56 O.Q28 0.635 

6 4 0.14 0.14 0.38 0.56 0.050 0.238 

7 4 0.14 0.14 0.38 0.56 0.030 0.192 

8 4 0.14 0.14 0.38 0.56 0.027 0.248 

9 4 0.14 0.14 0.38 0.56 0.022 0.592 

10 4 0.14 0.14 0.38 0.56 0.032 0.626 

11 4 0.14 0.14 0.38 0.56 0.050 0.255 

12 4 0.14 0.14 0.38 0.56 0.090 0.170 
Sanders Lead 

Troy, Alabama 

URS Corporation - North Carolina 

1600 Perimeter Park Drive 

Morrisville, North Carolina 27560 

Telepllone (919)461-1100 Fax (919)461-1415 

SCALE: DRAWN BY: SCL DATE: 8/4/09 

NA CHECKED BY: DATE: 

Location of Airport 

& Site 

File No. 

20499427 

Figure 1 
Sanders Lead 

Troy, Alabama 

SCALE: 

as shown 

White line = 1 km 

URS URS Corporation - North Carolina 

1600 Perimeter Park Drive 

Morrisville, North Carolina 27560 

Telephone (919)461-1100 Fax (919)461-1415 

DRAWN BY: SCL DATE: 8/4/09 

CHECKED BY: DATE: 

Aerials Extending 

1-km from Airport & 

Plant Site 

FILE NO. 

2049942 

FIG. NO. 

2 
60 

50 

Sanders Lead 

Troy, Alabama 

SCALE: 

na 

URS URS Corporation - North Carolina 

1600 Perimeter Park Drive 

Morrisville, North Carolina 27560 

Telephone (919)461-IIOO Fax (919)461-1415 

DRAWN BY: SCL DATE: 8/4/09 

CHECKED BY: DATE: 

Ill 

Land use Classes 

• 23 to 23 Ccmmllndustffrans 

IIIII 41 to 43 Fore.t 

.81 to 82 P .asture1Hay/C rops 

II 85 to 85 Urban Grass 

• 90 to 91 \1\body/Oiher Wetlan:ls 

FILE NO. 

AERSURFACE Output 

Surface Roughness 

Landuse Distribution 

2049942 

FIG. NO. 

Airport 

kil 

3 
Sanders Lead 

Troy, Alabama 

SCALE: 

na 

URS URS Corporation- North Carolina 

1600 Perimeter Park Drive 

Morrisville, North Carolina 27560 

Telephone (919)461-1100 Fax (919)461-1415 

DRAWN BY: SCL DATE: 7/9/09 

CHECKED BY: DATE: 

Landuse. Classes 

11 to 11 

llilll 21 to 22 

• 23 to 23 

33 to 33 

• 41. to 43 

81 to 82 

Ill 85 to 85 

• 91 to 92 

Water 

esidential 

c em m.-1 ndustn-r al"lS 

T ransitional 

F 

p 

u 

ors 

asture/Hay/Crcps 

rb.:n Grass 

Woo:ly/Other Wetlards 

AERSURFACE Output 

FILE NO. 

Surface Roughness 2049942 

Landuse Distribution FIG. NO. 

Plant Site 

(4 square kilometer area) 4 
Sanders Lead 

Troy, Alabama 

SCALE 

not shown 

\u 

/ 

I 

,./A-· 

/ 

With Site Landuse Data 

0 

0 ... 

Max. Location 

Max. Location 

I 

i.- -- - --

) 

/ 

I 

\---

With Airport Data 

URS URS Corporation - North Carolina 

1600 Perimeter Park Drive 

Morrisville, Norlh Carolina 27560 

Telepho11e (919)461-1100 Fax (919)461-1415 

cl 

A - - - - -- - ----

Maximum Receptor 

Location 

DRAWN BY: SCL DATE: 8/4/09 

2005 1st Quarter 

(with Airport and Site Landuse) 

CHECKED BY: DATE: 

FILE NO. 

2049942 

FIG. NO. 

5