Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-129 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-15k. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for IMPROVE Site James River Face. 

 The ranges in PM2.5 for Categories 3 and 4 are 20-25 and ≥ 25 μgm-3. 

Class 3 Class 4 

Bin 23 Bin 14 Bin 16 

Visibility Parameters 

Yesterday's FM at Richmond (μg/m3) 27.9 21.7 22.6 

Yesterday's FM at Greensboro-Winston-Salem (μg/m3) 27.7 19.8 25.2 

Yesterday's FM at Knoxville (μg/m3) 26.8 23.7 33.3 

Surface Meteorological Parameters 

Max. surface temperature (°C) 30.8 26.7 29.0 

Min. surface temperature (°C) 17.6 18.9 13.2 

Relative humidity (%) 72.8 83.8 69.4 

Surface wind speed (ms-1) 2.0 0.6 0.8 

Surface wind direction (degrees) 211 n/a 211 

Persistence 0.9 0.8 0.9 

Sea level pressure (mb) 1020 1023 1022 

Rainfall (inches) 0.1 0.1 0.0 

Rain (# periods) 0.8 1.0 0.0 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 16.3 14.3 13.9 

Temperature PM 850 mb (°C) 16.6 16.0 15.4 

Stability at Roanoke (°C) 3.8 0.1 4.9 

Geopotential height difference 700 mb at Roanoke (m) -22.4 25.4 -1.8 

Wind speed yesterday 700 mb at Dulles (ms-1) 7.9 6.3 4.9 

Wind speed yesterday 700 mb at Roanoke 

(ms-1) 5.6 6.2 4.9 

Wind direction yesterday 700 mb at Dulles (degrees) 278 270 352 

Wind direction yesterday 700 mb at Roanoke (degrees) 307 225 315 

Wind speed yesterday 850 mb at Dulles (ms-1) 5.3 3.3 4.2 

Wind speed yesterday 850 mb at Roanoke 

(ms-1) 3.1 4.4 2.7 

Wind speed AM 850 mb at Dulles (ms-1) 6.7 4.0 3.9 

Wind speed AM 850 mb at Roanoke (ms-1) 9.5 4.9 5.7 

Wind speed PM 850 mb at Dulles (ms-1) 9.0 4.9 5.1 

Wind speed PM 850 mb at Roanoke (ms-1) 9.1 6.2 3.5 

Wind direction yesterday 850 mb at Dulles (degrees) 278 252 259 

Wind direction yesterday 850 mb at Roanoke (degrees) 239 45 315 

Wind direction AM 850 mb at Dulles (degrees) 262 180 292 

Wind direction AM 850 mb at Roanoke (degrees) 262 180 284 

Wind direction PM 850 mb at Dulles (degrees) 243 198 270 

Wind direction PM 850 mb at Roanoke (degrees) 225 135 304 

Recirculation at Roanoke 0.0 0.3 0.3 

Cloud average 1.9 2.3 2.0 

Appendix B.7 - 163
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-130 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-15l. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for IMPROVE Site Linville Gorge. 

The ranges in PM2.5 for Categories 3 and 4 are 17.5-20 and ≥ 20 μgm-3. 

Class 3 Class 4 

Bin 30 Bin 19 Bin 25 

Visibility Parameters 

Yesterday's FM at Knoxville (μg/m3) 30.2 32.1 35.9 

Yesterday's FM at Charlotte (μg/m3) 26.4 15.7 30.0 

Yesterday's FM at Greensboro-Winston-Salem (μg/m3) 29.9 17.0 28.0 

Surface Meteorological Parameters 

Max. surface temperature (°C) 18.4 18.8 23.3 

Min. surface temperature (°C) 29.0 29.3 28.3 

Relative humidity (%) 19.6 16.9 16.4 

Surface wind speed (ms-1) 77.2 65.5 68.8 

Surface wind direction (degrees) 0.8 1.4 0.8 

Persistence 326 297 284 

Sea level pressure (mb) 0.6 0.7 0.7 

Rainfall (inches) 1018 1017 1021 

Rain (# periods) 0.1 0.0 0.0 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 16.6 15.8 14.7 

Temperature PM 850 mb (°C) 17.2 17.3 15.9 

Stability at Greensboro (°C) -0.2 2.9 1.1 

Geopotential height difference 700 mb at Greensboro (m) -12.3 -0.1 4.3 

Wind speed yesterday 700 mb at Greensboro (ms-1) 6 6 6 

Wind direction yesterday 700 mb at Greensboro (degrees) 270 326 342 

Wind speed yesterday 850 mb at Greensboro (ms-1) 4 6 5 

Wind speed AM 850 mb at Greensboro (ms-1) 5.8 6.4 5.0 

Wind speed PM 850 mb at Greensboro (ms-1) 5.8 4.7 5.1 

Wind direction yesterday 850 mb at Greensboro (degrees) 225 0 338 

Wind direction AM 850 mb at Greensboro (degrees) 342 288 315 

Wind direction PM 850 mb at Greensboro (degrees) 270 270 297 

Recirculation at Greensboro 0.0 0.2 0.1 

Cloud average 1.8 1.2 1.9 

Appendix B.7 - 164
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-131 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-15m. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for IMPROVE Site Mammoth Cave. 

The ranges in PM2.5 for Categories 3 and 4 are 20-25 and ≥ 25 μgm-3. 

Class 3 Class 4 

Bin 30 Bin 5 Bin 24 Bin 21 

Visibility Parameters 

Yesterday's FM at Nashville (μg/m3) 26.2 10.0 22.1 30.4 

Yesterday's FM at Knoxville (μg/m3) 30.4 16.1 36.4 30.9 

Yesterday's FM at Louisville (μg/m3) 33.1 18.5 28.2 34.8 

Surface Meteorological Parameters 

Max. surface temperature (°C) 31.3 28.8 28.9 30.8 

Min. surface temperature (°C) 21.2 19.0 19.2 17.2 

Relative humidity (%) 72.8 77.7 81.6 69.7 

Surface wind speed (ms-1) 2.7 0.8 0.8 1.0 

Surface wind direction (degrees) 236 n/a 108 252 

Persistence 0.8 0.6 0.6 0.7 

Sea level pressure (mb) 1018 1018 1016 1021 

Rainfall (inches) 0.4 0.0 0.5 0.0 

Rain (# periods) 1.4 0.0 0.8 0.3 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 17.2 14.7 16.4 15.9 

Temperature PM 850 mb (°C) 18.5 17.7 17.3 16.8 

Stability at Nashville (°C) -0.3 -1.0 0.2 1.7 

Geopotential height difference 700 mb at Nashville (m) -10.5 22.7 1.3 -0.7 

Wind speed yesterday 700 mb at Nashville (ms-1) 7.2 8.9 8.3 4.2 

Wind direction yesterday 700 mb at Nashville (degrees) 297 315 315 90 

Wind speed yesterday 850 mb at Nashville (ms-1) 4.7 6.3 2.8 3.5 

Wind speed AM 850 mb at Nashville (ms-1) 8.0 4.9 3.8 4.6 

Wind speed PM 850 mb at Nashville (ms-1) 6.6 3.5 4.6 4.5 

Wind direction yesterday 850 mb at Nashville (degrees) 239 288 135 297 

Wind direction AM 850 mb at Nashville (degrees) 270 315 225 297 

Wind direction PM 850 mb at Nashville (degrees) 225 270 315 180 

Recirculation at Nashville 0.0 0.3 0.5 0.3 

Cloud average 1.8 1.8 2.0 1.8 

Appendix B.7 - 165
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-132 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-15n. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for IMPROVE Site Mingo. 

The ranges in PM2.5 for Categories 3 and 4 are 20-25 and ≥ 25 μgm-3. 

Class 3 Class 4 

Bin 21 Bin 18 Bin 8 

Visibility Parameters 

Yesterday's FM at St. Louis (μg/m3) 33.2 25.8 17.5 

Surface Meteorological Parameters 

Max. surface temperature (°C) 24.7 26.6 27.4 

Min. surface temperature (°C) 9.6 14.8 10.8 

Relative humidity (%) 69.6 73.6 64.6 

Surface wind speed (ms-1) 0.8 1.3 2.1 

Surface wind direction (degrees) 256 162 214 

Persistence 0.8 0.8 0.9 

Sea level pressure (mb) 1025 1018 1022 

Rainfall (inches) 0.2 0.8 0.0 

Rain (# periods) 0.0 0.1 0.0 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 10.9 14.0 14.2 

Temperature PM 850 mb (°C) 11.1 15.1 15.3 

Stability at Little Rock (°C) -1.2 -1.9 0.7 

Geopotential height difference 700 mb at Little Rock (m) -7.4 -0.8 -6.4 

Wind speed yesterday 700 mb at Springfield (ms-1) 7.4 11.6 7.0 

Wind speed yesterday 700 mb at Little Rock (ms-1) 5.3 9.9 3.4 

Wind speed yesterday 700 mb at Lincoln (ms-1) 9.7 10.0 10.1 

Wind speed yesterday 700 mb at Nashville 

(ms-1) 3.4 6.8 6.7 

Wind direction yesterday 700 mb at Springfield (degrees) 236 243 256 

Wind direction yesterday 700 mb at Little Rock (degrees) 214 297 270 

Wind direction yesterday 700 mb at Lincoln (degrees) 256 301 256 

Wind direction yesterday 700 mb at Nashville (degrees) 90 252 270 

Wind speed yesterday 850 mb at Springfield (ms-1) 6.7 9.0 8.2 

Wind speed yesterday 850 mb at Little Rock (ms-1) 3.4 6.8 4.3 

Wind speed yesterday 850 mb at Lincoln (ms-1) 7.7 8.5 7.1 

Wind speed yesterday 850 mb at Nashville 

(ms-1) 4.7 4.6 5.1 

Wind speed AM 850 mb at Springfield (ms-1) 5.4 5.5 8.6 

Wind speed AM 850 mb at Little Rock (ms-1) 6.7 6.9 4.9 

Wind speed AM 850 mb at Lincoln (ms-1) 8.0 7.7 7.8 

Wind speed AM 850 mb at Nashville (ms-1) 5.8 7.1 6.7 

Wind speed PM 850 mb at Springfield (ms-1) 6.3 4.6 15.1 

Wind speed PM 850 mb at Little Rock (ms-1) 5.2 5.9 8.8 

Wind speed PM 850 mb at Lincoln (ms-1) 8.1 4.9 14.2 

Wind speed PM 850 mb at Nashville (ms-1) 5.9 5.1 6.5 

Wind direction yesterday 850 mb at Springfield (degrees) 194 202 180 

Wind direction yesterday 850 mb at Little Rock (degrees) 194 207 166 

Wind direction yesterday 850 mb at Lincoln (degrees) 236 252 270 

Appendix B.7 - 166
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-133 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Class 3 Class 4 

Bin 21 Bin 18 Bin 8 

Wind direction yesterday 850 mb at Nashville (degrees) 207 225 180 

Wind direction AM 850 mb at Springfield (degrees) 225 279 236 

Wind direction AM 850 mb at Little Rock (degrees) 225 236 214 

Wind direction AM 850 mb at Lincoln (degrees) 256 281 236 

Wind direction AM 850 mb at Nashville (degrees) 225 252 297 

Wind direction PM 850 mb at Springfield (degrees) 194 153 194 

Wind direction PM 850 mb at Little Rock (degrees) 214 191 194 

Wind direction PM 850 mb at Lincoln (degrees) 225 270 225 

Wind direction PM 850 mb at Nashville (degrees) 243 360 194 

Cloud average 2.0 1.6 1.4 

Appendix B.7 - 167
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-134 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-15o. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for Okefenokee. 

The ranges in PM2.5 for Categories 3 and 4 are 15-20 and ≥ 20 μgm-3. 

Class 3 Class 4 

Bin 28 Bin 31 Bin 3 Bin 30 

Visibility Parameters 

Yesterday's FM at Jacksonville (μg/m3) 18.3 30.2 9.5 30.2 

Surface Meteorological Parameters 

Max. surface temperature (°C) 31.0 27.1 30.8 32.7 

Min. surface temperature (°C) 19.3 15.6 17.5 21.6 

Relative humidity (%) 71.9 75.9 71.4 74.1 

Surface wind speed (ms-1) 2.0 2.6 2.1 1.5 

Surface wind direction (degrees) n/a 117 108 153 

Persistence 0.7 0.8 0.8 0.6 

Sea level pressure (mb) 1016 1022 1020 1016 

Rainfall (inches) 0.1 0.0 0.0 0.0 

Rain (# periods) 0.6 0.4 0.3 0.1 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 15.9 12.7 15.1 17.5 

Temperature PM 850 mb (°C) 16.6 13.0 16.1 18.1 

Stability at Jacksonville (°C) 0.3 -0.5 1.5 -0.4 

Geopotential height difference 700 mb at Jacksonville (m) -3.9 -4.8 2.5 -1.8 

Wind speed yesterday 700 mb at Jacksonville (ms-1) 8.5 7.5 5.9 8.6 

Wind speed yesterday 700 mb at Tallahassee (ms-1) 6.9 6.2 6.2 6.7 

Wind direction yesterday 700 mb at Jacksonville (degrees) 304 270 315 342 

Wind direction yesterday 700 mb at Tallahassee (degrees) 315 360 315 346 

Wind speed yesterday 850 mb at Jacksonville (ms-1) 6.2 5.6 3.5 4.3 

Wind speed yesterday 850 mb at Tallahassee (ms-1) 4.8 2.5 2.7 3.8 

Wind speed AM 850 mb at Jacksonville (ms-1) 6.7 7.6 4.7 5.2 

Wind speed AM 850 mb at Tallahassee (ms-1) 5.7 4.1 5.0 3.5 

Wind speed PM 850 mb at Jacksonville (ms-1) 5.4 7.6 3.3 4.8 

Wind speed PM 850 mb at Tallahassee (ms-1) 4.9 5.2 2.2 4.3 

Wind direction yesterday 850 mb at Jacksonville (degrees) 315 360 315 326 

Wind direction yesterday 850 mb at Tallahassee (degrees) 360 326 90 14 

Wind direction AM 850 mb at Jacksonville (degrees) 270 27 45 326 

Wind direction AM 850 mb at Tallahassee (degrees) 297 333 135 270 

Wind direction PM 850 mb at Jacksonville (degrees) 270 27 315 326 

Wind direction PM 850 mb at Tallahassee (degrees) 342 27 315 333 

Recirculation at Jacksonville 0.1 0.0 0.0 0.1 

Cloud average 1.6 1.4 1.8 1.9 

Appendix B.7 - 168
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-135 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-15p. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for IMPROVE Site Shenandoah. 

The ranges in PM2.5 for Categories 3 and 4 are 17.5-22.5 and ≥ 22.5 μgm-3. 

Class 3 Class 4 

Bin 13 Bin 25 Bin 28 Bin 16 

Visibility Parameters 

Yesterday's FM at Richmond (μg/m3) 18.5 28.2 27.6 18.6 

Yesterday's FM at DC (μg/m3) 22.5 29.7 32.6 24.5 

Yesterday's FM at Columbus (μg/m3) 17.5 28.5 34.4 34.2 

Surface Meteorological Parameters 

Max. surface temperature (°C) 21.2 21.6 24.1 22.9 

Min. surface temperature (°C) 14.8 13.2 18.4 15.7 

Relative humidity (%) 83.4 76.8 76.5 71.7 

Surface wind speed (ms-1) 1.1 2.3 1.5 0.7 

Surface wind direction (degrees) 180 315 207 117 

Persistence 0.7 0.9 0.8 0.5 

Rainfall (inches) 0.5 0.8 0.4 0.4 

Rain (# periods) 0.1 0.1 0.0 0.1 

Solar radiation (W/m2) 568 698 690 568 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 15.0 15.4 18.5 15.6 

Temperature PM 850 mb (°C) 16.6 15.3 18.9 17.3 

Stability at Dulles (°C) -0.8 0.6 1.6 2.8 

Geopotential height difference 700 mb at Dulles (m) 23.4 -25.8 6.0 5.7 

Wind speed yesterday 700 mb at Dulles (ms-1) 8.0 12.2 6.9 5.1 

Wind speed yesterday 700 mb at Roanoke 

(ms-1) 7.5 9.7 5.8 5.4 

Wind direction yesterday 700 mb at Dulles (degrees) 293 270 311 342 

Wind direction yesterday 700 mb at Roanoke (degrees) 278 236 360 304 

Wind speed yesterday 850 mb at Dulles (ms-1) 5.1 7.0 6.5 3.7 

Wind speed yesterday 850 mb at Roanoke 

(ms-1) 3.6 7.3 4.0 2.2 

Wind speed AM 850 mb at Dulles (ms-1) 4.5 10.7 6.1 3.2 

Wind speed AM 850 mb at Roanoke (ms-1) 4.2 12.1 7.3 3.7 

Wind speed PM 850 mb at Dulles (ms-1) 4.3 11.8 7.8 3.6 

Wind speed PM 850 mb at Roanoke (ms-1) 4.1 12.2 5.9 3.2 

Wind direction yesterday 850 mb at Dulles (degrees) 288 236 291 252 

Wind direction yesterday 850 mb at Roanoke (degrees) 315 270 309 270 

Wind direction AM 850 mb at Dulles (degrees) 259 252 297 315 

Wind direction AM 850 mb at Roanoke (degrees) 259 284 288 304 

Wind direction PM 850 mb at Dulles (degrees) 256 270 278 315 

Wind direction PM 850 mb at Roanoke (degrees) 211 284 281 180 

Recirculation at Dulles 0.2 0.0 0.1 0.5 

Cloud average 2.2 1.6 1.7 1.8 

Appendix B.7 - 169
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-136 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-15q. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for IMPROVE Site Shining Rock. 

The ranges in PM2.5 for Categories 3 and 4 are 15-20 and ≥ 20 μgm-3. 

Class 3 Class 4 

Bin 10 Bin 27 Bin 21 Bin 23 

Visibility Parameters 

Yesterday's FM at Knoxville (μg/m3) 19.6 30.6 31.0 35.8 

Yesterday's FM at Charlotte (μg/m3) 16.6 23.9 22.7 27.8 

Yesterday's FM at Greenville (μg/m3) 16.0 27.2 28.7 28.8 

Surface Meteorological Parameters 

Max. surface temperature (°C) 26.4 28.1 26.3 28.1 

Min. surface temperature (°C) 13.1 17.9 16.2 15.8 

Relative humidity (%) 74.5 81.3 74.6 73.7 

Surface wind speed (ms-1) 1.2 1.1 1.1 1.5 

Surface wind direction (degrees) 180 351 297 360 

Persistence 0.7 0.6 0.7 0.7 

Sea level pressure (mb) 1024 1018 1018 1020 

Rainfall (inches) 0.0 0.1 0.0 0.0 

Rain (# periods) 26.4 28.1 26.3 28.1 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 14.0 17.0 15.0 16.0 

Temperature PM 850 mb (°C) 15.2 17.6 15.1 17.3 

Stability at Greensboro (°C) 0.5 -0.4 0.4 0.7 

Geopotential height difference 700 mb at Greensboro (m) 13.2 -16.4 17.8 -3.2 

Wind speed yesterday 700 mb at Greensboro (ms-1) 8.7 7.4 9.2 6.9 

Wind direction yesterday 700 mb at Greensboro (degrees) 304 297 284 342 

Wind speed yesterday 850 mb at Greensboro (ms-1) 5.3 6.1 5.1 4.8 

Wind speed AM 850 mb at Greensboro (ms-1) 5.7 5.7 4.1 5.1 

Wind speed PM 850 mb at Greensboro (ms-1) 5.7 5.1 2.7 7.1 

Wind direction yesterday 850 mb at Greensboro (degrees) 270 281 315 284 

Wind direction AM 850 mb at Greensboro (degrees) 297 292 270 293 

Wind direction PM 850 mb at Greensboro (degrees) 198 256 360 278 

Recirculation at Greensboro 0.1 0.0 0.0 0.0 

Cloud average 2.1 1.9 1.6 1.6 

Appendix B.7 - 170
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-137 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-15r. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for IMPROVE Site Sipsey. 

The ranges in PM2.5 for Categories 3 and 4 are 17.5-22.5 and ≥ 22.5 μgm-3. 

Class 3 Class 4 

Bin 29 Bin 22 Bin 30 

Visibility Parameters 

Yesterday's FM at Birmingham (μg/m3) 33.1 43.3 45.6 

Yesterday's FM at Atlanta (μg/m3) 28.6 26.4 35.3 

Yesterday's FM at Nashville (μg/m3) 18.9 17.9 33.0 

Yesterday's FM at Memphis (μg/m3) 20.1 24.0 29.4 

Surface Meteorological Parameters 

Max. surface temperature (°C) 31.3 24.3 30.8 

Min. surface temperature (°C) 18.5 9.6 16.8 

Relative humidity (%) 70.4 69.8 66.7 

Surface wind speed (ms-1) 1.3 1.2 1.1 

Surface wind direction (degrees) 63 270 270 

Persistence 0.8 0.6 0.7 

Sea level pressure (mb) 1018 1022 1021 

Rainfall (inches) 0.1 0.0 0.0 

Rain (# periods) 0.3 0.0 0.5 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 17.0 9.6 15.0 

Temperature PM 850 mb (°C) 17.9 12.5 16.0 

Stability at Birmingham (°C) 1.5 1.4 2.5 

Geopotential height difference 700 mb at Birmingham (m) -2.0 24.0 -0.5 

Wind speed yesterday 700 mb at Birmingham (ms-1) 5.4 11.2 5.7 

Wind direction yesterday 700 mb at Birmingham (degrees) 45 207 60 

Wind speed yesterday 850 mb at Birmingham (ms-1) 5.5 6.7 4.3 

Wind speed AM 850 mb at Birmingham (ms-1) 4.5 9.0 4.9 

Wind speed PM 850 mb at Birmingham (ms-1) 4.6 7.0 4.9 

Wind direction yesterday 850 mb at Birmingham (degrees) 27 207 74 

Wind direction AM 850 mb at Birmingham 

(degrees) 180 225 108 

Wind direction PM 850 mb at Birmingham (degrees) 360 243 90 

Recirculation at Birmingham 0.1 0.0 0.2 

Cloud average 1.4 2.0 1.5 

Appendix B.7 - 171
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-138 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-15s. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for IMPROVE Site St. Marks. 

The ranges in PM2.5 for Categories 3 and 4 are 15-17.5 and ≥ 17.5 μgm-3. 

Class 3 Class 4 

Bin 22 Bin 30 Bin 19 

Visibility Parameters 

Yesterday's FM at Orlando (μg/m3) 16.4 17.6 11.3 

Yesterday's FM at Pensacola (μg/m3) 20.3 16.5 24.8 

Surface Meteorological Parameters 

Max. surface temperature (°C) 22.6 35.7 26.2 

Min. surface temperature (°C) 4.9 23.6 14.9 

Relative humidity (%) 68.4 70.6 73.6 

Surface wind speed (ms-1) 0.6 0.9 1.5 

Surface wind direction (degrees) 360 315 360 

Persistence 0.5 0.4 0.6 

Sea level pressure (mb) 1022 1016 1023 

Rainfall (inches) 0.0 0.0 0.1 

Rain (# periods) 0.5 0.5 0.7 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 11.8 19.2 14.3 

Temperature PM 850 mb (°C) 11.6 19.5 13.0 

Stability at Tallahassee (°C) 7.9 -0.1 -0.8 

Geopotential height difference 700 mb at Tallahassee (m) 13.6 -13.0 12.7 

Wind speed yesterday 700 mb at Tallahassee (ms-1) 8.3 4.4 8.7 

Wind direction yesterday 700 mb at Tallahassee (degrees) 270 0 315 

Wind speed yesterday 850 mb at Tallahassee (ms-1) 7.9 4.6 5.6 

Wind speed AM 850 mb at Tallahassee (ms-1) 6.5 3.3 5.6 

Wind speed PM 850 mb at Tallahassee (ms-1) 4.8 4.2 4.2 

Wind direction yesterday 850 mb at Tallahassee (degrees) 342 18 315 

Wind direction AM 850 mb at Tallahassee (degrees) 315 270 284 

Wind direction PM 850 mb at Tallahassee (degrees) 342 n/a 360 

Recirculation at Tallahassee 0.0 0.3 0.2 

Cloud average 1.5 1.8 1.3 

Appendix B.7 - 172
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-139 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-15t. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for IMPROVE Site Swanquarter. 

The ranges in PM2.5 for Categories 3 and 4 are 12.5-17.5 and ≥ 17.5 μgm-3. 

Class 3 Class 

Bin 21 Bin 17 Bin 13 Bin 28 

Visibility Parameters 

Yesterday's FM at Raleigh (μg/m3) 21.7 22.4 21.6 34.9 

Yesterday's FM at Norfolk (μg/m3) 19.2 15.2 19.7 35.8 

Surface Meteorological Parameters 

Max. surface temperature (°C) 26.5 25.4 15.7 29.7 

Min. surface temperature (°C) 20.7 17.9 7.2 24.0 

Relative humidity (%) 90.8 82.1 77.5 81.5 

Surface wind speed (ms-1) 3.5 3.0 1.6 4.2 

Surface wind direction (degrees) 210 243 349 270 

Persistence 0.8 0.7 0.6 0.9 

Sea level pressure (mb) 1017 1020 1025 1016 

Rainfall (inches) 0.0 0.1 0.0 0.1 

Rain (# periods) 0.5 0.8 0.2 0.3 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 16.6 14.7 8.8 17.7 

Temperature PM 850 mb (°C) 17.3 14.6 9.9 18.9 

Stability at Moorhead (°C) -0.1 -1.7 6.9 -1.5 

Geopotential height difference 700 mb at Moorhead (m) -6.2 4.8 11.2 -11.0 

Wind speed yesterday 700 mb at Moorhead (ms-1) 8 12 10 7 

Wind direction yesterday 700 mb at Moorhead (degrees) 276 270 304 342 

Wind speed yesterday 850 mb at Moorhead (ms-1) 6 9 7 4 

Wind speed AM 850 mb at Moorhead (ms-1) 7.3 9.1 6.7 7.7 

Wind speed PM 850 mb at Moorhead (ms-1) 6.3 7.3 7.0 7.2 

Wind direction yesterday 850 mb at Moorhead (degrees) 270 270 326 315 

Wind direction AM 850 mb at Moorhead (degrees) 275 270 304 288 

Wind direction PM 850 mb at Moorhead (degrees) 270 270 315 270 

Recirculation at Moorhead 0.1 0.2 0.0 0.0 

Cloud average 1.6 1.8 1.0 1.8 

Appendix B.7 - 173
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-140 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

 Table 3-15u. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for IMPROVE Site Upper Buffalo. 

The ranges in PM2.5 for Categories 3 and 4 are 15-17.5 and ≥ 17.5 μgm-3. 

Class 3 Class 4 

Bin 23 Bin 28 Bin 30 Bin 32 

Visibility Parameters 

Yesterday's FM at Little Rock (μg/m3) 17.6 25.8 23.4 30.0 

Yesterday's FM at Dallas (μg/m3) 17.5 21.1 16.6 24.8 

Surface Meteorological Parameters 

Max. surface temperature (°C) 29.3 23.9 33.6 32.2 

Min. surface temperature (°C) 17.4 14.0 21.0 20.4 

Relative humidity (%) 73.0 78.4 68.9 69.4 

Surface wind speed (ms-1) 2.4 2.2 1.7 1.7 

Surface wind direction (degrees) 166 135 90 194 

Persistence 0.8 0.8 0.8 0.7 

Sea level pressure (mb) 1020 1020 1018 1018 

Rainfall (inches) 0.0 0.2 0.0 0.0 

Rain (# periods) 0.0 0.5 0.0 0.2 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 16.4 13.5 19.2 18.2 

Temperature PM 850 mb (°C) 17.7 13.5 19.3 19.5 

Stability at Little Rock (°C) -2.9 -1.4 -2.7 -1.1 

Geopotential height difference 700 mb at Little Rock (m) 25.5 -9.4 6.8 0.4 

Wind speed yesterday 700 mb at Little Rock (ms-1) 4.9 2.7 8.1 5.2 

Wind direction yesterday 700 mb at Little Rock (degrees) 360 225 45 45 

Wind speed yesterday 850 mb at Little Rock (ms-1) 4.4 2.2 3.9 3.8 

Wind speed AM 850 mb at Little Rock (ms-1) 5.3 4.5 4.1 3.7 

Wind speed PM 850 mb at Little Rock (ms-1) 4.2 4.9 4.5 3.3 

Wind direction yesterday 850 mb at Little Rock (degrees) 117 162 45 270 

Wind direction AM 850 mb at Little Rock (degrees) 243 252 90 259 

Wind direction PM 850 mb at Little Rock (degrees) 194 180 90 236 

Recirculation at Little Rock 0.4 0.3 0.8 0.4 

Cloud average 1.8 1.5 1.5 1.6 

We discuss the findings for Cape Romain, Great Smoky Mountains, and Mammoth Cave below. 

For Cape Romain, the PM2.5 concentration ranges for Categories 3 and 4 are 15 to 17.5 and 

greater than or equal to 17.5 μgm-3, respectively. There are two Category 3 and two Category 4 

bins that meet the criteria for key bins. One of the Category 3 bins represents a fall, winter, or 

early spring regime, and is characterized by a relatively low average maximum temperature. 

The remaining three bins are characterized by high temperatures, low to moderate surface wind 

speeds, and moderate relative humidity, and these vary relative to one another among the bins. 

Prior day PM2.5 values for Charleston are in the range of 13 to 29 μgm-3, and are highest for the 

Category 4 bins. Average surface wind direction is southwesterly for three of the key bins, and 

southeasterly for the remaining key bin. Recirculation by the sea breeze (as indicated by 

persistence) appears to be important for Bin 22, which is a Category 5 bin. Stability is greatest, 

on average, for the cooler days in Bin 15. Upper-air wind speeds and directions vary slightly 

Appendix B.7 - 174
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-141 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

among the bins. Wind speeds are highest for the cooler regime (Bin 15). Morning and evening 

850 mb wind directions are northwesterly for all bins. A comparison of the two Category 4 bins 

shows that Bin 22 has lower temperatures, higher humidity, lower surface wind speeds, 

southeasterly surface winds, and greater cloud cover. Bin 33 has higher temperatures, lower 

humidity, higher surface wind speeds, southwesterly surface winds, and less cloud cover. 

Clearly, different combinations of local parameters can result in high PM2.5 concentrations. 

For GSM, the PM2.5 concentration ranges for Categories 3 and 4 are 17.5 to 25 and greater than 

or equal to 25 μgm-3, respectively. All four key bins are characterized by very low surface wind 

speeds and relatively high temperatures. All but one of the key bins is characterized by greater 

than 80 percent relative humidity. The Category 4 bin has the highest prior-day PM2.5

concentrations at the three potential upwind areas (Knoxville, Atlanta, and Charlotte). The 

greatest differences among the bins are the wind directions. An anticyclonic circulation aloft (a 

high pressure system) over the GSM region is indicated by the upper-level wind directions 

(southwesterly winds over Nashville, northwesterly winds over Greensboro, and southeasterly 

winds over Atlanta) for Bin 24 (the Category 4 bin). 

For Mammoth Cave, the PM2.5 concentration ranges for Categories 3 and 4 are 20 to 25 and 

greater than or equal to 25 μgm-3, respectively. All four key bins are characterized by high 

temperatures. Relative humidity varies among the bins and is lowest for Bin 21 (the Category 4 

bin). Average surface wind speed is very low for three of the bins, and somewhat higher 

(moderate) for Bin 30 (one of the Category 3 bins). Prior day PM2.5 values for Nashville, 

Knoxville, and Louisville vary among the bins, and the variation is not consistent among the 

three sites. Bin 5 is distinguished by low prior-day PM2.5 values for all three potential upwind 

areas. Average surface wind direction is southwesterly for Bins 30 and 21, southeasterly for Bin 

24, and not available (unable to be calculated) for Bin 5. Morning and evening 850 mb wind 

directions vary considerably among the key bins. Bin 21, the Category 4 bin, is distinguished 

from the Category 3 bins by higher prior-day PM2.5 concentrations at all three potential upwind 

sites, lower relative humidity, and a shift from northwesterly to southerly winds aloft during the 

daytime hours. 

Figure 3-7 shows the average composition for all key PM2.5 bins for each of the IMPROVE sites. 

Appendix B.7 - 175
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-7a. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Breton. 

Breton Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

7 (119) 1 (44) 11 (23) 4 (21) 13 (9) 8 (4) 19 (13) 27 (7) 21 (10)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure 3-7b. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Brigantine. 

Brigantine Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

1 (219) 8 (91) 16 (12) 25 (12) 23 (14) 29 (4) 31 (12)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-142 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 176
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-7c. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Cadiz. 

Cadiz Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

8 (141) 14 (39) 27 (29) 24 (13) 21 (12) 23 (8) 6 (5) 30 (9)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure 3-7d. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Caney Creek. 

Caney Creek Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

3 (164) 18 (43) 5 (26) 11 (14) 22 (12) 31 (10) 13 (7) 32 (6) 27 (5) 29 (10)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-143 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 177
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-7e. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Cape Romain. 

Cape Romain Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

1 (191) 13 (59) 8 (37) 29 (17) 20 (14) 18 (11) 6 (10) 15 (4) 31 (4) 22 (11) 33 (7)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure 3-7f. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Chassahowitzka. 

Chassahowitzka Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

5 (117) 2 (23) 22 (21) 23 (6) 21 (9) 12 (5) 13 (10) 8 (8) 27 (9)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-144 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 178
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-7g. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Cohutta. 

Cohutta Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

1 (179) 7 (26) 5 (15) 13 (18) 2 (11) 23 (9) 21 (10) 29 (12)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure 3-7h. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Dolly Sods. 

Dolly Sods Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

4 (237) 10 (23) 1 (20) 17 (34) 7 (22) 21 (11) 18 (4) 23 (11) 27 (4)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-145 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 179
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-7i. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Everglades. 

Everglades Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

1 (184) 11 (65) 7 (17) 28 (25) 15 (19) 19 (9) 21 (5) 27 (5) 2 (4)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure 3-7j. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Great Smoky Mountains. 

Great Smoky Mountains Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

3 (291) 4(42) 17 (20) 20 (20) 22 (12) 5 (8) 11 (10) 13 (7) 26 (7) 24 (14)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-146 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 180
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-7k. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

James River Face. 

James River Face Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

1 (174) 25 (51) 28 (45) 9 (28) 26 (18) 19 (12) 23 (8) 14 (4) 16 (8)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure 3-7l. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Linville Gorge. 

Linville Gorge Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

1 (227) 6 (49) 21 (17) 18 (22) 15 (11) 31 (9) 30 (5) 19 (5) 25 (15)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-147 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 181
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-7m. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate 

(SO4) Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE 

Site Mammoth Cave. 

Mammoth Cave Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

10 (221) 1 (55) 19 (25) 9 (22) 13 (14) 30 (10) 5 (4) 24 (4) 21 (16)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure 3-7n. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Mingo. 

Mingo Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14 (68) 1 (26) 12 (10) 22 (9) 7 (7) 18 (10) 8 (5) 21 (5)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-148 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 182
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-7o. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Okefenokee. 

Okefenokee Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

18 (157) 1 (51) 8 (37) 10 (17) 12 (10) 27 (14) 28 (14) 31 (5) 3 (4) 30 (7)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure 3-7p. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Shenandoah. 

Shenandoah Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

2 (202) 3 (43) 18 (30) 20 (15) 22 (13) 13 (12) 25 (5) 28 (13) 16 (5)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-149 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 183
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-7q. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Shining Rock. 

Shining Rock Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

5 (191) 20 (37) 4 (19) 14 (15) 9 (15) 10 (8) 27 (7) 21 (5) 23 (12)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure 3-7r. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Sipsey. 

Sipsy Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

1 (190) 8 (41) 16 (18) 15 (10) 3 (8) 24 (8) 29 (7) 22 (3) 30 (11)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-150 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 184
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-7s. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

St Mark’s. 

St. Marks Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

4 (90) 5 (50) 7 (29) 27 (13) 13 (10) 9 (9) 22 (4) 30 (4) 19 (6)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure 3-7t. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Swanquarter. 

Swanquarter Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

5 (160) 24 (29) 16 (11) 12 (9) 21 (13) 17 (5) 13 (6) 28 (4)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-151 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 185
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-7u. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: IMPROVE Site 

Upper Buffalo. 

Upper Buffalo Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

2 (167) 17 (33) 21 (38) 20 (15) 12 (10) 23 (5) 28 (4) 30 (4) 32 (16)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

The compositional charts for PM2.5 also clearly illustrate that the relative contributions of various PM2.5

components vary by bin for each of the sites. As for visibility, the high PM2.5 concentration bins are 

distinguished from the lower concentration bins by higher sulfate and organic matter concentrations, 

and, in many cases, lower nitrate concentrations. Within each category, the variations among the bins 

are due to differences in meteorology as well as regional pollutant transport. 

Table 3-16 summarizes the characteristics for key Category 3 and 4 bins for the STN monitoring sites. 

ICF International 3-152 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 186
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-153 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16a. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Birmingham. 

The ranges in PM2.5 for Categories 3 and 4 are 32.5-40 and ≥ 40 μgm-3. 

Class 3 Class 4 

Bin 11 Bin 26 Bin 19 Bin 10 

PM2.5 Parameters 

Yesterday's FM at Birmingham (μg/m3) 30.5 32.6 50.7 32.4 

Yesterday's FM at Atlanta (μg/m3) 23.2 24.1 37.6 25.6 

Yesterday's FM at Memphis (μg/m3) 21.5 27.9 28.3 22.2 

Yesterday's FM at Nashville (μg/m3) 22.0 31.3 27.7 19.5 

Surface Meteorological Parameters 

Max. surface temperature (°C) 27.9 34.0 28.3 29.6 

Min. surface temperature (°C) 14.8 22.7 14.5 14.6 

Relative humidity (%) 61.3 61.2 63.1 61.6 

Surface wind speed (ms-1) 1.0 2.2 0.7 0.3 

Surface wind direction (degrees) 90 81 342 112 

Persistence 0.7 0.9 0.8 0.5 

Sea level pressure (mb) 1021 1017 1022 1023 

Rainfall (inches) 0.0 0.0 0.0 0.0 

Rain (# periods) 0.3 0.3 0.1 0.2 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 13.8 18.2 13.6 14.6 

Temperature PM 850 mb (°C) 15.0 19.3 14.4 15.9 

Stability at Birmingham (°C) 3.6 0.8 4.5 4.0 

Geopotential height difference 700 mb at Birmingham (m) -3.2 6.7 1.3 5.9 

Wind speed yesterday 700 mb at Birmingham (ms-1) 6.9 9.2 5.8 6.0 

Wind direction yesterday 700 mb at Birmingham (degrees) 24 22 34 22 

Wind speed yesterday 850 mb at Birmingham (ms-1) 4.6 6.5 3.6 4.5 

Wind speed AM 850 mb at Birmingham (ms-1) 5.5 4.6 3.7 4.0 

Wind speed PM 850 mb at Birmingham (ms-1) 5.1 6.9 2.9 3.2 

Wind direction yesterday 850 mb at Birmingham (degrees) 24 22 34 22 

Wind direction AM 850 mb at Birmingham (degrees) 243 56 270 45 

Wind direction PM 850 mb at Birmingham (degrees) 60 68 270 180 

Recirculation at Birmingham 0.1 0.0 0.4 0.2 

Cloud average 1.6 1.7 1.5 1.5 

Appendix B.7 - 187
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-154 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16b. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Charlotte. 

 The ranges in PM2.5 for Categories 3 and 4 are 22.5-30 and ≥ 30 μgm-3. 

Class 3 Class 4 

Bin 31 Bin 15 Bin 12 Bin 18 Bin 26 

PM2.5 Parameters 

Yesterday's FM at Atlanta (μg/m3) 28.2 33.4 20.6 23.2 35.2 

Yesterday's FM at Charlotte (μg/m3) 28.6 20.1 19.3 18.8 32.2 

Yesterday's FM at Greenville-Spartanburg (μg/m3) 27.2 19.0 18.3 18.3 30.4 

Yesterday's FM at Winston-Salem (μg/m3) 29.2 19.7 20.8 22.4 31.7 

Surface Meteorological Parameters 

Max. surface temperature (°C) 31.2 23.6 26.0 33.7 29.2 

Min. surface temperature (°C) 19.7 10.6 16.5 20.3 16.7 

Relative humidity (%) 70.2 66.8 71.0 62.2 69.1 

Surface wind speed (ms-1) 1.8 1.3 1.6 1.1 1.2 

Surface wind direction (degrees) 207 194 102 209 185 

Persistence 0.7 0.8 0.6 0.7 0.7 

Sea level pressure (mb) 1019 1022 1021 1018 1020 

Rainfall (inches) 0.2 0.0 0.4 0.0 0.0 

Rain (# periods) 0.6 0.2 0.6 0.3 0.3 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 17.1 10.3 12.1 18.2 15.2 

Temperature PM 850 mb (°C) 17.6 12.2 12.7 19.5 15.7 

Stability at Greensboro (°C) 0.5 3.6 -0.4 1.7 1.4 

Geopotential height difference 700 mb at Greensboro (m) -6.6 6.6 25.5 2.3 -1.5 

Wind speed yesterday 700 mb at Greensboro (ms-1) 9.1 9.2 10.0 7.0 6.5 

Wind direction yesterday 700 mb at Greensboro (degrees) 286 288 306 319 326 

Wind speed yesterday 850 mb at Greensboro (ms-1) 5.8 5.4 5.5 4.1 5.0 

Wind speed AM 850 mb at Greensboro (ms-1) 8.6 6.1 4.7 5.1 3.9 

Wind speed PM 850 mb at Greensboro (ms-1) 7.0 7.5 4.1 5.2 5.2 

Wind direction yesterday 850 mb at Greensboro (degrees) 259 247 301 301 309 

Wind direction AM 850 mb at Greensboro (degrees) 278 246 307 323 302 

Wind direction PM 850 mb at Greensboro (degrees) 273 270 n/a 270 278 

Recirculation at Greensboro 0 0.1 0.3 0.1 0.2 

Cloud average 1.8 1.4 2 1.7 1.5 

Appendix B.7 - 188
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-155 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16c. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Chattanooga. 

The ranges in PM2.5 for Categories 3 and 4 are 25-32.5 and ≥ 32.5 μgm-3. 

Class 3 Class 4 

Bin 22 Bin 19 Bin 21 Bin 28 

PM2.5 Parameters 

Yesterday's FM at Birmingham (μg/m3) 34.5 30.2 36.9 44.8 

Yesterday's FM at Atlanta (μg/m3) 24.4 23.3 27.1 45.4 

Yesterday's FM at Knoxville (μg/m3) 25.9 26.4 26.5 44.7 

Surface Meteorological Parameters 

Max. surface temperature (°C) 30.0 29.8 34.3 26.1 

Min. surface temperature (°C) 16.7 18.7 21.1 13.9 

Relative humidity (%) 69.6 73.3 61.2 73.2 

Surface wind speed (ms-1) 0.8 0.8 1.7 0.7 

Surface wind direction (degrees) 225 194 243 180 

Persistence 0.8 0.6 0.7 0.8 

Sea level pressure (mb) 1022 1021 1017 1024 

Rainfall (inches) 0.1 0.1 0.1 0.0 

Rain (# periods) 0.3 0.9 0.6 0.5 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 15.8 14.7 18.6 12.5 

Temperature PM 850 mb (°C) 16.3 16.0 19.1 12.9 

Stability at Atlanta (°C) 4.5 3.2 5.3 4.9 

Geopotential height difference 700 mb at Atlanta (m) -7.4 -3.4 -4.5 -9.1 

Wind speed yesterday 700 mb at Atlanta (ms-1) 6.1 5.3 5.6 3.9 

Wind speed yesterday 700 mb at Nashville (ms-1) 7.6 7.5 6.4 5.6 

Wind direction yesterday 700 mb at Atlanta (degrees) 34 108 27 117 

Wind direction yesterday 700 mb at Nashville (degrees) 270 243 326 90 

Wind speed yesterday 850 mb at Atlanta (ms-1) 4.4 4.2 3.8 4.3 

Wind speed yesterday 850 mb at Nashville (ms-1) 4.4 5.5 4.6 4.6 

Wind speed AM 850 mb at Atlanta (ms-1) 4.6 4.5 4.9 4.3 

Wind speed AM 850 mb at Nashville (ms-1) 7.7 7.3 6.7 6.9 

Wind speed PM 850 mb at Atlanta (ms-1) 5.3 4.1 6.0 6.0 

Wind speed PM 850 mb at Nashville (ms-1) 6.2 6.3 6.2 6.5 

Wind direction yesterday 850 mb at Atlanta (degrees) 90 90 360 90 

Wind direction yesterday 850 mb at Nashville (degrees) 180 281 326 207 

Wind direction AM 850 mb at Atlanta (degrees) 270 90 360 90 

Wind direction AM 850 mb at Nashville (degrees) 236 248 307 236 

Wind direction PM 850 mb at Atlanta (degrees) 127 90 27 225 

Wind direction PM 850 mb at Nashville (degrees) 214 217 297 225 

Cloud average 1.9 2.1 1.9 1.9 

Appendix B.7 - 189
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-156 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16d. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Greenville-Spartanburg. 

The ranges in PM2.5 for Categories 3 and 4 are 22.5-30 and ≥ 30 μgm-3. 

Class 3 Class 4 

Bin 20 Bin 25 Bin 22 Bin32 Bin 21 Bin30 

PM2.5 Parameters 

Yesterday's FM at Atlanta (μg/m3) 27.1 36.1 24.9 40.2 26.0 30.1 

Yesterday's FM at Columbus (μg/m3) 17.7 28.4 16.6 29.3 17.9 25.4 

Yesterday's FM at Charlotte (μg/m3) 23.9 30.1 24.8 32.9 26.3 25.5 

Yesterday's FM at Greensboro (μg/m3) 25.2 32.8 24.6 34.1 26.7 23.3 

Surface Meteorological Parameters 

Max. surface temperature (°C) 28.0 28.9 29.5 28.5 26.8 29.6 

Min. surface temperature (°C) 17.3 18.9 19.2 18.0 13.4 20.1 

Relative humidity (%) 67.8 75.7 70.2 71.9 69.6 70.6 

Surface wind speed (ms-1) 2.2 1.4 2.1 1.8 1.9 1.4 

Surface wind direction (degrees) 195 236 63 236 112 90 

Persistence 0.8 0.7 0.8 0.8 0.8 0.8 

Sea level pressure (mb) 1019 1018 1021 1020 1022 1020 

Rainfall (inches) 0.0 0.2 0.0 0.1 0.0 0.0 

Rain (# periods) 0.6 0.9 0.5 0.4 0.0 0.0 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 14.3 15.8 15.8 14.8 13.1 15.5 

Temperature PM 850 mb (°C) 16.1 16.2 16.5 15.5 14.1 16.8 

Stability at Atlanta (°C) 2.4 2.1 0.0 3.0 2.7 2.5 

Geopotential height difference 700 mb at Atlanta (m) -6.5 -20.5 9.2 9.8 -10.3 14.1 

Wind speed yesterday 700 mb at Atlanta (ms-1) 6.0 5.6 4.82 5.5 6.5 6.6 

Wind speed yesterday 700 mb at Greensboro (ms-1) 8.4 6.2 4.4 7.3 5.9 5.1 

Wind direction yesterday 700 mb at Atlanta (degrees) 278 14 108 310 45 34 

Wind direction yesterday 700 mb at Greensboro (degrees) 283 326 270 287 9 346 

Wind speed yesterday 850 mb at Atlanta (ms-1) 5.0 4.9 4.4 4.2 4.8 3.5 

Wind speed yesterday 850 mb at Greensboro (ms-1) 5.9 5.9 6.2 5.4 4.0 3.7 

Wind speed AM 850 mb at Atlanta (ms-1) 6.8 5.0 5.0 5.3 4.2 4.0 

Wind speed AM 850 mb at Greensboro (ms-1) 7.6 5.2 6.5 6.1 3.5 3.7 

Wind speed PM 850 mb at Atlanta (ms-1) 6.4 4.9 5.3 5.1 4.2 4.1 

Wind speed PM 850 mb at Greensboro (ms-1) 7.0 5.9 5.1 6.6 3.9 4.6 

Wind direction yesterday 850 mb at Atlanta (degrees) 140 284 79 171 90 360 

Wind direction yesterday 850 mb at Greensboro (degrees) 270 270 56 270 27 31 

Wind direction AM 850 mb at Atlanta (degrees) 239 360 59 234 227 34 

Wind direction AM 850 mb at Greensboro (degrees) 257 307 74 266 27 34 

Wind direction PM 850 mb at Atlanta (degrees) 250 207 74 211 146 90 

Wind direction PM 850 mb at Greensboro (degrees) 249 270 90 274 225 90 

Cloud average 2.0 2.2 2.4 1.9 2.0 1.8 

Appendix B.7 - 190
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-157 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16e. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Hickory. 

 The ranges in PM2.5 for Categories 3 and 4 are 27.5-32.5 and ≥ 32.5 μgm-3. 

Class 3 Class 4 

Bin 29 Bin 27 Bin 22 Bin 17 

PM2.5 Parameters 

Yesterday's FM at Charlotte (μg/m3) 27.7 29.3 30.4 21.5 

Yesterday's FM at Greensboro (μg/m3) 25.6 33.9 30.3 21.6 

Yesterday's FM at Knoxville (μg/m3) 29.0 34.2 36.5 23.5 

Yesterday's FM at Winston-Salem (μg/m3) 31.3 29.4 31.9 19.1 

Surface Meteorological Parameters 

Max. surface temperature (°C) 28.5 25.8 29.5 23.5 

Min. surface temperature (°C) 17.5 14.7 18.0 12.0 

Relative humidity (%) 70.2 71.9 71.5 71.2 

Surface wind speed (ms-1) 1.9 0.8 0.8 1.4 

Surface wind direction (degrees) 315 45 270 14 

Persistence 0.8 0.8 0.7 0.8 

Sea level pressure (mb) 1020 1019 1020 1023 

Rainfall (inches) 0.0 0.0 0.0 0.0 

Rain (# periods) 0.5 0.8 0.5 0.4 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 15.3 14.9 16.2 10.2 

Temperature PM 850 mb (°C) 15.6 16.2 16.6 12.1 

Stability at Greensboro (°C) 0.3 1.3 -0.9 2.6 

Geopotential height difference 700 mb at Greensboro (m) -5.5 2.1 7.7 -4.0 

Wind speed yesterday 700 mb at Greensboro (ms-1) 7.9 9.3 6.7 8.9 

Wind direction yesterday 700 mb at Greensboro (degrees) 288 315 333 284 

Wind speed yesterday 850 mb at Greensboro (ms-1) 3.6 9.2 3.3 5.9 

Wind speed AM 850 mb at Greensboro (ms-1) 6.5 7.6 5.8 6.9 

Wind speed PM 850 mb at Greensboro (ms-1) 6.2 5.0 5.2 5.2 

Wind direction yesterday 850 mb at Greensboro (degrees) 288 342 292 360 

Wind direction AM 850 mb at Greensboro (degrees) 360 n/a 277 270 

Wind direction PM 850 mb at Greensboro (degrees) 225 270 281 45 

Recirculation at Greensboro 0.0 0.0 0.2 0.0 

Cloud average 1.6 1.5 1.9 1.8 

Appendix B.7 - 191
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-158 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16f. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Huntington-Ashland. 

The ranges in PM2.5 for Categories 3 and 4 are 25-32.5 and ≥ 32.5 μgm-3. 

Class 3 Class 4 

Bin 14 Bin 12 Bin 23 

PM2.5 Parameters 

Yesterday's FM at Louisville (μg/m3) 27.9 28.7 40.2 

Yesterday's FM at Cincinnati (μg/m3) 26.8 24.2 44.7 

Surface Meteorological Parameters 

Max. surface temperature (°C) 27.8 29.4 29.1 

Min. surface temperature (°C) 15.8 17.6 17.4 

Relative humidity (%) 74.8 77.6 75.0 

Surface wind speed (ms-1) 1.2 0.8 0.9 

Surface wind direction (degrees) 162 135 214 

Persistence 0.7 0.6 0.8 

Sea level pressure (mb) 1020 1020 1023 

Rainfall (inches) 0.0 0.0 0.0 

Rain (# periods) 0.8 0.5 0.8 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 14.1 15.8 14.7 

Temperature PM 850 mb (°C) 15.3 16.7 16.0 

Stability at Wilmington (°C) 1.5 2.4 1.3 

Geopotential height difference 700 mb at Wilmington (m) -6.6 -7.0 -16.3 

Wind speed yesterday 700 mb at Nashville (ms-1) 7.6 5.1 4.4 

Wind speed yesterday 700 mb at Roanoke (ms-1) 4.3 5.9 4.7 

Wind direction yesterday 700 mb at Nashville (degrees) 198 360 117 

Wind direction yesterday 700 mb at Roanoke (degrees) 297 315 22 

Wind speed yesterday 850 mb at Wilmington (ms-1) 5.8 5.7 3.5 

Wind speed yesterday 850 mb at Nashville (ms-1) 5.5 4.2 3.6 

Wind speed yesterday 850 mb at Roanoke (ms-1) 4.3 5.2 3.8 

Wind speed AM 850 mb at Wilmington (ms-1) 6.8 4.2 6.4 

Wind speed AM 850 mb at Nashville (ms-1) 6.9 2.5 3.8 

Wind speed AM 850 mb at Roanoke (ms-1) 4.2 6.8 6.6 

Wind speed PM 850 mb at Wilmington (ms-1) 9.4 5.6 6.1 

Wind speed PM 850 mb at Nashville (ms-1) 6.2 4.0 5.1 

Wind speed PM 850 mb at Roanoke (ms-1) 4.9 4.9 5.6 

Wind direction yesterday 850 mb at Wilmington (degrees) 207 288 236 

Wind direction yesterday 850 mb at Nashville (degrees) 194 315 207 

Wind direction yesterday 850 mb at Roanoke (degrees) 135 315 14 

Wind direction AM 850 mb at Wilmington (degrees) 252 270 281 

Wind direction AM 850 mb at Nashville (degrees) 270 225 207 

Wind direction AM 850 mb at Roanoke (degrees) 214 288 342 

Wind direction PM 850 mb at Wilmington (degrees) 233 270 270 

Wind direction PM 850 mb at Nashville (degrees) 207 270 207 

Wind direction PM 850 mb at Roanoke (degrees) 169 270 342 

Recirculation at Wilmington 0 0.3 0.1 

Cloud average 1.8 2.0 1.8 

Appendix B.7 - 192
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-159 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16g. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Jackson. 

The ranges in PM2.5 for Categories 3 and 4 are 22.5-27.5 and ≥ 27.5 μgm-3. 

Class 3 Class 4 

Bin 30 Bin 34 Bin 22 

PM2.5 Parameters 

Yesterday's FM at Birmingham (μg/m3) 38.7 42.8 41.3 

Yesterday's FM at Memphis (μg/m3) 24.8 23.8 28.0 

Yesterday's FM at Gulfport (μg/m3) 24.0 21.2 23.2 

Yesterday's FM at New Orleans/Baton Rouge (μg/m3) 26.5 25.1 25.7 

Surface Meteorological Parameters 

Max. surface temperature (°C) 29.0 29.7 30.4 

Min. surface temperature (°C) 17.3 14.0 17.6 

Relative humidity (%) 70.1 67.6 69.9 

Surface wind speed (ms-1) 1.2 1.4 0.8 

Surface wind direction (degrees) 63 90 146 

Persistence 0.7 0.9 0.8 

Sea level pressure (mb) 1018 1021 1019 

Rainfall (inches) 0.1 0.0 0.0 

Rain (# periods) 0.7 0.3 0.2 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 14 16.2 15.1 

Temperature PM 850 mb (°C) 16.2 15.3 16.6 

Stability at Jacksonville (°C) -0.3 4.7 1.8 

Geopotential height difference 700 mb at Jacksonville (m) -3.8 2.3 1.3 

Wind speed yesterday 700 mb at Jacksonville (ms-1) 5.8 5.8 5.9 

Wind direction yesterday 700 mb at Jacksonville (degrees) 270 45 76 

Wind speed yesterday 850 mb at Jacksonville (ms-1) 4.0 5.4 4.4 

Wind speed AM 850 mb at Jacksonville (ms-1) 6.7 7.4 3.0 

Wind speed PM 850 mb at Jacksonville (ms-1) 6.0 6.9 1.7 

Wind direction yesterday 850 mb at Jacksonville (degrees) 117 n/a 76 

Wind direction AM 850 mb at Jacksonville (degrees) 191 n/a 171 

Wind direction PM 850 mb at Jacksonville (degrees) 180 n/a 180 

Recirculation at Jacksonville 0.1 0.0 0.4 

Cloud average 2 1.6 1.6 

Appendix B.7 - 193
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-160 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16h. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Kingsport-Bristol. 

The ranges in PM2.5 for Categories 3 and 4 are 25-32.5 and ≥ 32.5 μgm-3. 

Class 3 Class 4 

PM2.5 Parameters Bin 27 Bin 3 Bin 24 Bin 32 

Yesterday's FM at Louisville (μg/m3) 28.6 17.1 28.8 41.4 

Yesterday's FM at Knoxville (μg/m3) 39.1 24.9 20.5 38.7 

Yesterday's FM at Winston-Salem (μg/m3) 28.9 21.1 21.9 26.2 

Yesterday's FM at Richmond (μg/m3) 23.3 12.7 19.4 22.1 

Surface Meteorological Parameters 

Max. surface temperature (°C) 30.4 25.9 28.7 27.2 

Min. surface temperature (°C) 18.0 12.4 15.7 14.7 

Relative humidity (%) 73.0 72.3 75.5 77.4 

Surface wind speed (ms-1) 0.8 0.6 0.9 0.7 

Persistence 0.7 0.7 0.7 0.8 

Sea level pressure (mb) 1019 1022 1019 1022 

Surface wind direction (degrees) 198 256 236 270 

Rainfall (inches) 0.1 0.0 0.1 0.0 

Rain (# periods) 0.6 0.0 0.6 0.6 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 17.2 13.1 15.9 15.3 

Temperature PM 850 mb (°C) 18.3 14.3 16.8 16.3 

Stability at Roanoke (°C) 2.6 3.9 4.2 5.3 

Geopotential height difference 700 mb at Roanoke (m) 2.6 -0.2 3.9 -11.6 

Wind speed yesterday 700 mb at Nashville (ms-1) 6.2 7.7 6.3 4.6 

Wind speed yesterday 700 mb at Roanoke (ms-1) 7.9 7.0 6.5 5.2 

Wind direction yesterday 700 mb at Nashville (degrees) 270 270 297 360 

Wind direction yesterday 700 mb at Roanoke (degrees) 284 286 292 360 

Wind speed yesterday 850 mb at Nashville (ms-1) 4.9 4.2 5.4 3.6 

Wind speed yesterday 850 mb at Roanoke (ms-1) 4.6 4.5 5.0 4.3 

Wind speed AM 850 mb at Nashville (ms-1) 6.7 5.6 8.3 6.1 

Wind speed AM 850 mb at Roanoke (ms-1) 5.4 5.7 8.8 8.3 

Wind speed PM 850 mb at Nashville (ms-1) 7.5 5.0 5.7 6.1 

Wind speed PM 850 mb at Roanoke (ms-1) 5.4 3.5 7.6 6.4 

Wind direction yesterday 850 mb at Nashville (degrees) 217 27. 248 194 

Wind direction yesterday 850 mb at Roanoke (degrees) 288 214 256 351 

Wind direction AM 850 mb at Nashville (degrees) 247 297 270 239 

Wind direction AM 850 mb at Roanoke (degrees) 281 315 270 329 

Wind direction PM 850 mb at Nashville (degrees) 236 217 256 243 

Wind direction PM 850 mb at Roanoke (degrees) 236 .270 236 301 

Cloud average 1.9 1.8 2.1 2.0 

Appendix B.7 - 194
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-161 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16i. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Louisville. 

The ranges in PM2.5 for Categories 3 and 4 are 27.5-37.5 and ≥ 37.5 μgm-3. 

Class 3 Class 4 

Bin 15 Bin 30 Bin 17 Bin 24 Bin 25 Bin 29 

PM2.5 Parameters 

Yesterday's FM at Nashville (μg/m3) 16.7 28.5 29.0 29.4 29.1 25.9 

Yesterday's FM at Louisville (μg/m3) 29.5 37.0 31.1 35.7 38.5 33.3 

Yesterday's FM at Cincinnati (μg/m3) 25.7 37.6 31.9 32.5 32.2 32.6 

Yesterday's FM at St. Louis (μg/m3) 15.9 29.9 17.9 32.0 27.4 28.6 

Surface Meteorological Parameters 

Max. surface temperature (°C) 32.4 26.3 32.8 28.9 34.1 22.6 

Min. surface temperature (°C) 22.4 16.2 22.3 18.1 22.2 12.5 

Relative humidity (%) 67.3 69.4 65.6 68.9 55.4 78.1 

Surface wind speed (ms-1) 1.7 2.8 2.8 1.6 1.1 1.0 

Surface wind direction (degrees) 243 202 221 225 9. 135 

Persistence 0.7 0.8 0.8 0.7 0.7 0.6 

Sea level pressure (mb) 1017 1020 1018 1019 1023 1023 

Rainfall (inches) 0.1 0.1 0.2 0.1 0.0 0.1 

Rain (# periods) 0.6 0.5 0.7 0.6 0.0 0.5 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 17.1 13.8 17.2 14.8 17.2 11.6 

Temperature PM 850 mb (°C) 17.8 14.0 17.8 15.4 18.6 11.8 

Stability at Wilmington (°C) 1.4 2.5 0.3 2.8 2.9 1.7 

Geopotential height difference 700 mb at Wilmington (m) -11.0 -2.4 -12.5 -7.8 14.3 16.5 

Wind speed yesterday 700 mb at Wilmington (ms-1) 5.8 9.6 11.1 5.6 4.2 10.0 

Wind speed yesterday 700 mb at Nashville (ms-1) 5.3 7.4 5.3 5.9 5.5 7.7 

Wind direction yesterday 700 mb at Wilmington (degrees) 284 286 270 299 243 297 

Wind direction yesterday 700 mb at Nashville (degrees) 288 207 180 351 117 45 

Wind speed yesterday 850 mb at Wilmington (ms-1) 5.0 7.6 8.8 3.1 2.2 8.5 

Wind speed yesterday 850 mb at Nashville (ms-1) 3.9 3.9 5.0 3.5 2.8 6.1 

Wind speed AM 850 mb at Wilmington (ms-1) 4.9 10.1 9.8 5.9 3.0 5.8 

Wind speed AM 850 mb at Nashville (ms-1) 3.9 6.8 6.9 5.2 4.2 5.6 

Wind speed PM 850 mb at Wilmington (ms-1) 6.4 9.4 9.4 6.7 2.7 5.0 

Wind speed PM 850 mb at Nashville (ms-1) 4.6 6.5 6.4 5.2 3.2 4.8 

Wind direction yesterday 850 mb at Wilmington (degrees) 315 254 266 225 117 315 

Wind direction yesterday 850 mb at Nashville (degrees) 297 270 197 117 108 315 

Wind direction AM 850 mb at Wilmington (degrees) 270 277 266 273 315 360 

Wind direction AM 850 mb at Nashville (degrees) 243 254 250 259 45 45 

Wind direction PM 850 mb at Wilmington (degrees) 262 279 264 275 117 360 

Wind direction PM 850 mb at Nashville (degrees) 270 236 229 261 76 135 

Cloud average 2.0 1.7 1.8 1.9 1.7 1.7 

Appendix B.7 - 195
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-162 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16j. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Macon. 

The ranges in PM2.5 for Categories 3 and 4 are 25-30 and ≥ 30 μgm-3. 

Class 3 Class 4 

Bin 19 Bin 14 

PM2.5 Parameters 

Yesterday's FM at Atlanta (μg/m3) 30.0 31.1 

Surface Meteorological Parameters 

Max. surface temperature (°C) 33.8 27.1 

Min. surface temperature (°C) 20.9 10.4 

Relative humidity (%) 68.2 67.2 

Surface wind speed (ms-1) 0.6 0.7 

Surface wind direction (degrees) 153 225 

Persistence 0.4 0.7 

Sea level pressure (mb) 1017 1021 

Rainfall (inches) 0.0 0.0 

Rain (# periods) 0.2 0.4 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 17.7 12.1 

Temperature PM 850 mb (°C) 18.0 12.9 

Stability at Atlanta (°C) 3.2 7.4 

Geopotential height difference 700 mb at Atlanta (m) 7.4 12.0 

Wind speed yesterday 700 mb at Atlanta (ms-1) 0.6 0.7 

Wind direction yesterday 700 mb at Atlanta (degrees) 27 326 

Wind speed yesterday 850 mb at Atlanta (ms-1) 3.3 4.5 

Wind speed AM 850 mb at Atlanta (ms-1) 2.8 5.7 

Wind speed PM 850 mb at Atlanta (ms-1) 4.9 4.7 

Wind direction yesterday 850 mb at Atlanta (degrees) 34 342 

Wind direction AM 850 mb at Atlanta (degrees) 225 333 

Wind direction PM 850 mb at Atlanta (degrees) 207 326 

Recirculation at Atlanta 0.2 0.1 

Cloud average 1.6 1.5 

Appendix B.7 - 196
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-163 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16k. Summary of Average Input Parameters for Each Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Memphis. 

The ranges in PM2.5 for Categories 3 and 4 are 22.5-30 and ≥ 30 μgm-3. 

Class 4 Class 5 

Bin 14 Bin 5 Bin 25 Bin 15 Bin 32 Bin 22 

PM2.5 Parameters 

Yesterday's FM at Birmingham (μg/m3) 34.6 30.7 29.6 32.2 34.7 27.5 

Yesterday's FM at Memphis (μg/m3) 21.8 15.3 21.4 23.0 35.0 23.1 

Yesterday's FM at Nashville (μg/m3) 22.1 18.7 19.4 23.0 30.1 25.3 

Yesterday's FM at St. Louis (μg/m3) 21.2 18.4 19.7 19.0 31.5 24.7 

Yesterday's FM at Little Rock (μg/m3) 21.9 16.6 19.0 26.5 29.0 19.5 

Surface Meteorological Parameters 

Max. surface temperature (°C) 31.0 28.3 23.4 33.4 28.8 24.5 

Min. surface temperature (°C) 20.2 17.4 11.2 23.8 18.8 16.6 

Relative humidity (%) 59.4 57.4 62.1 63.9 64/3 68.8 

Surface wind speed (ms-1) 2.4 2.3 2.8 2.0 2.0 2.0 

Surface wind direction (degrees) 157 117 180 180 174 360 

Persistence 0.8 0.9 0.9 0.8 0.8 0.8 

Sea level pressure (mb) 1020 1021 1022 1019 1019 1019 

Rainfall (inches) 0.0 0.0 0.1 0.0 0.0 0.0 

Rain (# periods) 0.2 0.4 0.4 0.7 0.2 0.3 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 15.4 12.5 11.2 17.9 14.8 13.1 

Temperature PM 850 mb (°C) 16.2 13.7 11.8 18.7 15.4 13.7 

Stability at Nashville (°C) 2.3 1.5 5.6 -0.3 1.9 0.3 

Geopotential height difference 700 mb at Nashville (m) 5.0 8.0 -3.9 -78.3 -5.9 2.9 

Wind speed yesterday 700 mb at Nashville (ms-1) 4.2 4.9 6.8 11.0 7.4 6.5 

Wind speed yesterday 700 mb at Little Rock (ms-1) 5.7 5.1 6.1 5.8 7.6 7.0 

Wind direction yesterday 700 mb at Nashville (degrees) 319 90 326 326 24 63 

Wind direction yesterday 700 mb at Little Rock (degrees) 135 90 270 315 90 360 

Wind speed yesterday 850 mb at Nashville (ms-1) 3.8 5.3 3.1 3.9 4.6 5.1 

Wind speed yesterday 850 mb at Little Rock (ms-1) 4.6 5.4 4.7 2.9 5.3 4.4 

Wind speed AM 850 mb at Nashville (ms-1) 4.8 3.7 8.0 4.9 4.6 4.8 

Wind speed AM 850 mb at Little Rock (ms-1) 5.8 3.8 7.4 3.9 5.7 4.2 

Wind speed PM 850 mb at Nashville (ms-1) 4.3 3.7 12.7 4.5 5.1 5.2 

Wind speed PM 850 mb at Little Rock (ms-1) 5.2 4.2 7.7 2.2 6.1 5.2 

Wind direction yesterday 850 mb at Nashville (degrees) 221 162 360 360 330 27 

Wind direction yesterday 850 mb at Little Rock (degrees) 170 108 221 207 135 360 

Wind direction AM 850 mb at Nashville (degrees) 262 270 243 292 292 117 

Wind direction AM 850 mb at Little Rock (degrees) 196 153 233 270 204 326 

Wind direction PM 850 mb at Nashville (degrees) 193 135 236 284 304 360 

Wind direction PM 850 mb at Little Rock (degrees) 187 135 225 270 173 90 

Cloud average 1.8 1.9 1.5 1.9 1.9 2.3 

Appendix B.7 - 197
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Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-164 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16l. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Montgomery. 

The ranges in PM2.5 for Categories 3 and 4 are 25-30 and ≥ 30 μgm-3. 

Class 3 Class 4 

Bin 19 Bin 31 Bin 26 Bin 14 

PM2.5 Parameters 

Yesterday's FM at Birmingham (μg/m3) 31.8 34.8 47.1 30.9 

Yesterday's FM at Atlanta (μg/m3) 25.4 33.6 35.7 32.9 

Yesterday's FM at New Orleans/Baton Rouge (μg/m3) 19.3 22.7 23.0 22.4 

Surface Meteorological Parameters 

Max. surface temperature (°C) 32.9 31.7 31.8 30.4 

Min. surface temperature (°C) 21.0 20.3 18.4 21.0 

Relative humidity (%) 71.3 66.2 65.3 75.6 

Surface wind speed (ms-1) 0.9 2.7 0.8 1.0 

Surface wind direction (degrees) 270 90 270 90 

Persistence 0.6 0.9 0.7 0.6 

Sea level pressure (mb) 1019 1020 1020 1017 

Rainfall (inches) 0.2 0.0 0.0 0.1 

Rain (# periods) 0.9 0.2 0.4 1.0 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 32.9 31.7 31.8 30.4 

Temperature PM 850 mb (°C) 18.7 16.6 16.6 16.3 

Stability at Birmingham (°C) 1.0 0.9 2.8 0.2 

Geopotential height difference 700 mb at Birmingham (m) 0.2 6.1 -4.9 -5.3 

Wind speed yesterday 700 mb at Birmingham (ms-1) 6.8 5.3 5.1 7.6 

Wind direction yesterday 700 mb at Birmingham (degrees) 270 180 326 45 

Wind speed yesterday 850 mb at Birmingham (ms-1) 7.1 5.8 3.6 4.7 

Wind speed AM 850 mb at Birmingham (ms-1) 4.6 5.7 4.7 4.3 

Wind speed PM 850 mb at Birmingham (ms-1) 6.4 4.3 4.0 2.2 

Wind direction yesterday 850 mb at Birmingham (degrees) 360 270 333 326 

Wind direction AM 850 mb at Birmingham (degrees) 256 180 284 284 

Wind direction PM 850 mb at Birmingham (degrees) 27 207 346 270 

Recirculation at Birmingham 0.0 0.2 0.2 0.6 

Cloud average 1.6 1.8 1.8 2.2 

Appendix B.7 - 198
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Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-165 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16m. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Nashville. 

The ranges in PM2.5 for Categories 3 and 4 are 25-32.5 and ≥ 32.5 μgm-3. 

Class 3 Class 4 

Bin 19 Bin 16 Bin 27 Bin 25 Bin 20 

PM2.5 Parameters 

Yesterday's FM at Birmingham (μg/m3) 29.4 30.8 28.6 40.1 24.2 

Yesterday's FM at Memphis (μg/m3) 24.5 20.3 28.1 29.5 24.4 

Yesterday's FM at Nashville (μg/m3) 27.9 21.0 30.1 32.0 29.0 

Yesterday's FM at Louisville (μg/m3) 26.4 23.5 32.2 31.5 42.1 

Yesterday's FM at Cincinnati (μg/m3) 24.3 23.3 31.6 33.5 29.1 

Yesterday's FM at Knoxville (μg/m3) 21.5 23.3 24.5 36.3 20.6 

Surface Meteorological Parameters 

Max. surface temperature (°C) 23.2 32.2 31.2 30.3 33.2 

Min. surface temperature (°C) 12.2 20.4 20.8 18.1 21.4 

Relative humidity (%) 69.5 66.1 61.6 64.8 67.0 

Surface wind speed (ms-1) 1.5 1.7 2.8 1.3 1.4 

Surface wind direction (degrees) 194 180 315 180 360 

Persistence 0.7 0.7 0.9 0.7 0.7 

Sea level pressure (mb) 1021 1020 1018 1022 1017 

Rainfall (inches) 0.0 0.0 0.0 0.0 0.0 

Rain (# periods) 0.3 0.4 0.1 0.2 0.2 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 10.5 16.7 16.8 15.8 19.8 

Temperature PM 850 mb (°C) 11.8 17.9 16.8 16.4 20.8 

Stability at Nashville (°C) 1.4 1.0 0.5 1.6 0.2 

Geopotential height difference 700 mb at Nashville (m) 9.9 15.3 -9.8 -0.6 10.2 

Wind speed yesterday 700 mb at Nashville (ms-1) 7.9 4.4 6.6 5.2 7.4 

Wind direction yesterday 700 mb at Nashville (degrees) 328 315 333 90 27 

Wind speed yesterday 850 mb at Nashville (ms-1) 4.9 3.9 4.8 4.3 4.6 

Wind speed AM 850 mb at Nashville (ms-1) 5.4 6.1 6.6 5.6 6.0 

Wind speed PM 850 mb at Nashville (ms-1) 5.1 5.3 5.9 5.0 4.5 

Wind direction yesterday 850 mb at Nashville (degrees) 281 214 315 225 27 

Wind direction AM 850 mb at Nashville (degrees) 301 261 329 243 360 

Wind direction PM 850 mb at Nashville (degrees) 236 211 315 180 360 

Recirculation at Nashville 0.1 0.1 0.1 0.2 0.2 

Cloud average 1.6 1.8 1.5 1.9 1.6 

Appendix B.7 - 199
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Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-166 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16n. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Raleigh. 

 The ranges in PM2.5 for Categories 3 and 4 are 22.5-30 and ≥ 30 μgm-3. 

Class 3 Class 4 

Bin 22 Bin 23 Bin 9 Bin 28 Bin 30 Bin 26 

PM2.5 Parameters 

Yesterday's FM at Charlotte (μg/m3) 19.7 23.6 20.3 31.0 29.3 32.4 

Yesterday's FM at Richmond (μg/m3) 18.7 16.7 19.0 31.0 27.0 26.6 

Yesterday's FM at Raleigh (μg/m3) 18.9 26.3 18.6 31.8 31.4 30.7 

Yesterday's FM at Winston-Salem (μg/m3) 20.7 25.4 22.4 31.2 30.6 27.2 

Surface Meteorological Parameters 

Max. surface temperature (°C) 32.4 23.1 24.8 33.0 34.2 25.1 

Min. surface temperature (°C) 18.9 11.8 13.9 20.5 21.6 12.0 

Relative humidity (%) 67.8 76.1 73.7 69.9 71.6 71.4 

Surface wind speed (ms-1) 1.3 1.9 1.3 1.7 2.2 2.0 

Surface wind direction (degrees) 211 243 124 239 211 27 

Persistence 0.7 0.8 0.8 0.8 0.7 0.8 

Sea level pressure (mb) 1019 1020 1022 1018 1017 1022 

Rainfall (inches) 0.2 0.1 0.1 0.0 0.0 0.0 

Rain (# periods) 0.4 0.7 0.5 0.2 0.7 0.2 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 16.5 11.7 11.8 17.1 18.6 12.3 

Temperature PM 850 mb (°C) 18.1 10.9 13.3 18.0 19.0 12.4 

Stability at Greensboro (°C) 1.0 1.3 -0.3 0.4 0.9 2.1 

Geopotential height difference 700 mb at Greensboro (m) 2.1 -23.6 28.4 -1.6 -8.1 6.0 

Wind speed yesterday 700 mb at Greensboro (ms-1) 7.9 11.1 10.4 6.4 8.7 9.4 

Wind direction yesterday 700 mb at Greensboro (degrees) 7 276 309 306 270 346 

Wind speed yesterday 850 mb at Greensboro (ms-1) 4.3 6.9 6.3 5.0 5.0 5.5 

Wind speed AM 850 mb at Greensboro (ms-1) 3.8 9.9 6.1 3.9 9.8 6.7 

Wind speed PM 850 mb at Greensboro (ms-1) 3.6 7.3 5.6 4.3 9.1 6.0 

Wind direction yesterday 850 mb at Greensboro (degrees) 339 236 297 294 261 360 

Wind direction AM 850 mb at Greensboro (degrees) 342 256 270 302 286 14 

Wind direction PM 850 mb at Greensboro (degrees) 270 259 270 277 262 326 

Recirculation at Greensboro 0.2 0.1 0.2 0.1 0.0 0.2 

Cloud average 1.7 1.8 1.8 1.5 1.7 1.4 

Appendix B.7 - 200
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Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-167 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16o. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Richmond. 

The ranges in PM2.5 for Categories 3 and 4 are 25-30 and ≥ 30 μgm-3. 

Class 3 Class 4 

Bin 8 Bin 12 Bin 16 Bin 24 Bin 33 Bin 32 

PM2.5 Parameters 

Yesterday's FM at Richmond (μg/m3) 13.1 21.7 21.9 26.6 37.2 22.7 

Yesterday's FM at Winston-Salem (μg/m3) 16.0 21.9 22.6 16.3 33.5 25.7 

Yesterday's FM at Washington, D.C. (μg/m3) 15.5 20.8 21.7 37.9 42.2 28.0 

Surface Meteorological Parameters 

Max. surface temperature (°C) 30.3 26.3 22.3 25.3 34.8 33.6 

Min. surface temperature (°C) 19.0 16.7 10.9 14.5 22.6 20.6 

Relative humidity (%) 70.4 80.2 72.3 78.6 68.8 68.1 

Surface wind speed (ms-1) 1.6 2.2 1.2 1.9 2.3 1.9 

Surface wind direction (degrees) 326 146 104 144 216 198 

Persistence 0.7 0.8 0.6 0.8 0.7 0.8 

Sea level pressure (mb) 1018 1020 1020 1020 1018 1020 

Rainfall (inches) 0.2 0.0 0.1 0.0 0.1 0.0 

Rain (# periods) 0.9 0.5 0.9 0.7 0.7 0.2 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 14.9 12.5 9.1 12.5 18.3 18.1 

Temperature PM 850 mb (°C) 16.4 13.8 10.4 13.6 19.3 18.1 

Stability at Dulles (°C) 1.4 0.8 1.6 2.3 1.1 3.9 

Geopotential height difference 700 mb at Dulles (m) 13.3 3.1 13.8 -4.8 12.0 5.6 

Wind speed yesterday 700 mb at Roanoke (ms-1) 10.2 8.0 11.5 7.4 6.0 6.3 

Wind speed yesterday 700 mb at Dulles (ms-1) 9.7 8.1 13.7 9.9 8.2 8.0 

Wind direction yesterday 700 mb at Roanoke (degrees) 307 270 270 288 315 360 

Wind direction yesterday 700 mb at Dulles (degrees) 292 309 270 275 300 6 

Wind speed yesterday 850 mb at Roanoke (ms-1) 5.0 4.6 6.7 5.0 4.9 3.7 

Wind speed yesterday 850 mb at Dulles (ms-1) 7.5 3.9 10.2 6.2 6.7 6.1 

Wind speed AM 850 mb at Roanoke (ms-1) 6.0 6.8 7.3 6.9 8.2 7.7 

Wind speed AM 850 mb at Dulles (ms-1) 8.9 5.5 8.6 7.4 7.0 6.4 

Wind speed PM 850 mb at Roanoke (ms-1) 5.3 4.9 7.5 7.4 5.9 6.5 

Wind speed PM 850 mb at Dulles (ms-1) 7.7 7.0 8.0 8.2 7.7 8.2 

Wind direction yesterday 850 mb at Roanoke (degrees) 323 270 270 262 276 301 

Wind direction yesterday 850 mb at Dulles (degrees) 323 270 270 275 291 326 

Wind direction AM 850 mb at Roanoke (degrees) 360 259 270 270 275 225 

Wind direction AM 850 mb at Dulles (degrees) 351 309 278 270 290 278 

Wind direction PM 850 mb at Roanoke (degrees) 346 198 214 254 270 252 

Wind direction PM 850 mb at Dulles (degrees) 338 217 270 259 270 270 

Cloud average 1.9 1.9 2.0 1.9 1.8 1.7 

Appendix B.7 - 201
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Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-168 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-16p. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for STN Site Savannah. 

The ranges in PM2.5 for Categories 3 and 4 are 22.5-27.5 and ≥ 27.5 μgm-3. 

Class 3 Class 4 

Bin 17 Bin 5 Bin 25 

PM2.5 Parameters 

Yesterday's FM at Atlanta (μg/m3) 23.8 30.4 31.5 

Yesterday's FM at Charleston (μg/m3) 18.4 11.2 26.1 

Surface Meteorological Parameters 

Max. surface temperature (°C) 25.9 29.6 30.9 

Min. surface temperature (°C) 12.7 6.0 19.3 

Relative humidity (%) 71.7 67.2 71.3 

Surface wind speed (ms-1) 0.9 0.8 1.3 

Surface wind direction (degrees) 45 236 207 

Persistence 0.7 0.4 0.7 

Sea level pressure (mb) 1022 1017 1019 

Rainfall (inches) 0.0 0.0 0.0 

Rain (# periods) 0.1 0.4 0.0 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 11.0 12.9 15.8 

Temperature PM 850 mb (°C) 12.0 14.4 16.4 

Stability at Charleston (°C) 1.8 1.1 -1.4 

Geopotential height difference 700 mb at Charleston (m) 5.8 17.1 -0.9 

Wind speed yesterday 700 mb at Atlanta (ms-1) 8.6 9.1 8.6 

Wind speed yesterday 700 mb at Charleston (ms-1) 7.3 13.3 7.6 

Wind direction yesterday 700 mb at Atlanta (degrees) 315 360 338 

Wind direction yesterday 700 mb at Charleston (degrees) 315 315 342 

Wind speed yesterday 850 mb at Atlanta (ms-1) 5.1 7.4 3.8 

Wind speed yesterday 850 mb at Charleston (ms-1) 5.8 8.6 5.8 

Wind speed AM 850 mb at Atlanta (ms-1) 4.8 6.7 7.1 

Wind speed AM 850 mb at Charleston (ms-1) 4.7 8.0 6.9 

Wind speed PM 850 mb at Atlanta (ms-1) 5.6 5.8 5.3 

Wind speed PM 850 mb at Charleston (ms-1) 6.2 6.1 6.0 

Wind direction yesterday 850 mb at Atlanta (degrees) 288 333 304 

Wind direction yesterday 850 mb at Charleston (degrees) 346 288 321 

Wind direction AM 850 mb at Atlanta (degrees) 288 304 18 

Wind direction AM 850 mb at Charleston (degrees) 342 284 326 

Wind direction PM 850 mb at Atlanta (degrees) 284 326 304 

Wind direction PM 850 mb at Charleston (degrees) 333 304 349 

Cloud 1.9 2.0 1.8 

For Charlotte, the PM2.5 concentration ranges for Categories 3 and 4 are 22.5 to 30 and greater 

than or equal to 30 μgm-3, respectively. There are four Category 3 and one Category 4 key bins. 

All of the key high PM2.5 bins are characterized by low surface wind speeds, and moderate 

relative humidity. Average temperatures and, to some extent, humidity vary relative among the 

bins. Bins 15 and 12 (two of the Category 3 bins) have lower temperatures, typical of spring or 

Appendix B.7 - 202
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Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-169 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

fall. Prior day PM2.5 values at the potential upwind sites are consistently highest for Bin 26, the 

Category 4 bin. With the exception of Atlanta, the regional concentrations vary consistently 

among the bins. Average surface wind direction is southwesterly for four of the five key bins, 

and southeasterly for the remaining key bin (Bin 12). Stability is greatest, on average, for the 

cooler days in Bin 15. Upper-air wind speeds and directions vary only slightly among the bins. 

Morning and evening 850 mb wind directions are northwesterly for all bins. The higher regional 

concentrations are the most distinguishing feature of the Category 4 bin. Thus, regional buildup/transport appears to drive high PM2.5 in Charlotte. 

For Chattanooga, the PM2.5 concentration ranges for Categories 3 and 4 are 25 to 32.5 and 

greater than or equal to 32.5 μgm-3, respectively. There are three Category 3 and one Category 

4 bins that meet the criteria for key bins. All of the key high PM2.5 bins are characterized by very 

low surface wind speeds and moderate relative humidity. Average temperature ranges from 

moderate to high and varies among the bins. Bins 28 (the Category 4 bin) has the lowest 

temperatures, both near the surface and aloft. Prior day PM2.5 values for at the potential upwind 

sites are consistently highest for Bin 28, the Category 4 bin. Average surface wind direction is 

southwesterly for the three key Category 3 bins, and southerly for the Category 4 bin. Upper-air 

wind directions vary considerably among the bins. Southwesterly winds over Nashville and 

easterly followed by southwesterly winds aloft over Atlanta characterize the Bin 28 (Category 4). 

Average conditions for days within Bin 28 are similar in many respects to those for Bin 19, 

cooler temperatures and much higher regional concentrations appear to influence the higher 

PM2.5 concentrations for Bin 28. 

For Louisville, the PM2.5 concentration ranges for Categories 3 and 4 are 27.5 to 37.5 and 

greater than or equal to 37.5 μgm-3, respectively. There are three Category 3 and three 

Category 4 bins that meet the criteria for key bins. The Category 4 bins have lower average 

wind speeds and a greater tendency for easterly wind components. The Category 4 bins are 

characterized by a range of temperature, humidity, and wind direction. All are associated with 

low wind speeds and high prior-day PM2.5 concentrations at potential upwind sites. Bin 29 has 

the lowest average temperature and the highest average relative humidity value. This bin is also 

characterized by southeasterly surface winds and northerly to easterly winds aloft. Bin 24 is 

distinguished by southwesterly to westerly winds both near the surface and aloft. Bin 25 is 

characterized by very high average temperatures and low relative humidity. Winds are from the 

northeast near the surface and from the northwest to the southeast aloft. Winds speeds aloft are 

low, compared to other bins. For Louisville, CART appears to have identified three distinct high 

PM2.5 concentration regimes. 

For Macon, the PM2.5 concentration ranges for Categories 3 and 4 are 25 to 30 and greater than 

or equal to 30 μgm-3, respectively. There is one key bin for each category. Both are 

characterized, on average, by very low surface wind speeds, moderate relative humidity, and 

prior-day PM2.5 concentrations of about 30 μgm-3 in the Atlanta area. Bin 19 (Category 3) has 

higher temperatures and lower wind speeds aloft. Surface wind directions are from the 

southeast, and upper air wind directions are from the southwest. Bin 14 (Category 4) has cooler 

temperatures and greater stability. Surface wind directions are from the southwest, and upper 

air wind directions are from the northwest. Local conditions combined with a greater potential for 

pollutant transport from Atlanta appear to drive the higher PM2.5 concentrations for Bin 14. 

Appendix B.7 - 203
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Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-8 shows the average composition for all key PM2.5 bins for each of the STN sites. Note 

that for some sites and bins, there were insufficient speciated data to compute the bin averages. 

These are marked with an asterisk. 

Figure 3-8a. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site 

Birmingham. 

Birmingham Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

24.00

4 (417) 8 (193) 24 (97) 2 (38) 25 (27) 6 (24) 11 (45) 26 (7) 19 (23) 10 (11)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure 3-8b. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site 

Charlotte. 

Charlotte Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

1 (739) 21 (121) 20 (73) 6 (83) 8 (15) 31 (27) 15 (18) 12 (14) 18 (14) 26 (31)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO4

OM

SO4

ICF International 3-170 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 204
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Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-8c. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site 

Chattanooga. 

Chattanooga Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

7 (193) 2 (69) 12 (48) 6 (24) 17 (21) 10 (15) 22 (11) 19 (7) 21 (7) 28 (10)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure 3-8d. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site 

Greenville-Spartanburg. 

Greenville-Spartanburg Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

1 (711) 15

(121)

2 (62) 8 (63) 6 (71) 3 (23) 11 (9) 20 (28) 25 (11) 22 (10) 32 (4) 21 (4) 30 (4)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

* * *

Greenville-Spartanburg Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

1 (711) 15

(121)

2 (62) 8 (63) 6 (71) 3 (23) 11 (9) 20 (28) 25 (11) 22 (10) 32 (4) 21 (4) 30 (4)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

* * *

* No speciated data for this bin 

ICF International 3-171 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 205
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Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-8e. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site 

Hickory. 

Hickory Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

2 (272) 8 (35) 13 (21) 12 (18) 6 (10) 18 (6) 29 (8) 27 (6) 22 (11) 17 (5)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

* *

Hickory Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

2 (272) 8 (35) 13 (21) 12 (18) 6 (10) 18 (6) 29 (8) 27 (6) 22 (11) 17 (5)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

* *

* No speciated data for this bin 

Figure 3-8f. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site 

Huntington-Ashland. 

Huntington-Ashland Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

8 (243) 7 (40) 5 (22) 29 (20) 28 (20) 1 (14) 6 (11) 13 (10) 14 (10) 12 (8) 23 (9)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-172 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 206
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-8g. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site 

Jackson. 

Jackson Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

1 (175) 7 (38) 20 (23) 15 (27) 11 (18) 5 (15) 30 (7) 34 (8) 22 (9)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

*

Jackson Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

1 (175) 7 (38) 20 (23) 15 (27) 11 (18) 5 (15) 30 (7) 34 (8) 22 (9)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

*

* No speciated data for this bin 

Figure 3-8h. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site 

Kingsport-Bristol. 

Kingsport-Bristol Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

24.00

1 (254) 19 (43) 20 (23) 16 (22) 9 (16) 5 (6) 23 (10) 27 (12) 3 (9) 24 (7) 32 (9)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-173 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 207
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-8i. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site 

Louisville. 

Louisville Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

24.00

1 (724) 3 (153) 10 (104) 12 (79) 2 (31) 4 (28) 15 (12) 30 (13) 17 (15) 24 (26) 25 (7) 29 (6)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

* *

Louisville Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

24.00

1 (724) 3 (153) 10 (104) 12 (79) 2 (31) 4 (28) 15 (12) 30 (13) 17 (15) 24 (26) 25 (7) 29 (6)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

* *

* No speciated data for this bin 

Figure 3-8j. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site Macon. 

Macon Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

1 (158) 11 (49) 29 (28) 5 (29) 10 (27) 28 (14) 25 (12) 19 (5) 14 (14)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-174 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 208
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-8k. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site 

Memphis. 

Memphis Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

1 (645) 6 (125) 10 (111) 12 (35) 9 (26) 27 (23) 14 (37) 5 (8) 25 (8) 15 (9) 32 (34) 22 (7)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

*

Memphis Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

1 (645) 6 (125) 10 (111) 12 (35) 9 (26) 27 (23) 14 (37) 5 (8) 25 (8) 15 (9) 32 (34) 22 (7)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

*

* No speciated data for this bin 

Figure 3-8l. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site 

Montgomery. 

Montgomery Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

1 (242) 5 (69) 2 (19) 13 (18) 30 (11) 18 (13) 19 (7) 31 (5) 26 (11) 14 (5)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-175 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 209
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-8m. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate 

(SO4) Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site 

Nashville. 

Nashville Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

3 (556) 7 (337) 12 (90) 11 (64) 5 (40) 15 (22) 19 (22) 16 (10) 27 (8) 25 (21) 20 (5)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

*

Nashville Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

3 (556) 7 (337) 12 (90) 11 (64) 5 (40) 15 (22) 19 (22) 16 (10) 27 (8) 25 (21) 20 (5)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

*

* No speciated data for this bin 

Figure 3-8n. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site 

Raleigh. 

Raleigh Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

24.00

1 (615) 4 (239) 2 (144) 13 (57) 24 (17) 16 (19) 22 (20) 23 (11) 9 (12) 28 (20) 30 (10) 26 (5)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

* *

Raleigh Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

24.00

1 (615) 4 (239) 2 (144) 13 (57) 24 (17) 16 (19) 22 (20) 23 (11) 9 (12) 28 (20) 30 (10) 26 (5)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

* *

* No speciated data for this bin 

ICF International 3-176 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 210
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-8o. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site 

Richmond. 

Richmond Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

24.00

1 (640) 2 (133) 6 (66) 9 (69) 7 (46) 3 (17) 19 (21) 8 (7) 12 (12) 16 (9) 24 (16) 33 (18) 32 (10)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

* No speciated data for this bin 

Figure 3-8p. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: STN Site 

Savannah. 

Savannah Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

9 (217) 8 (61) 14 (55) 18 (8) 11 (6) 3 (6) 17 (8) 5 (5) 25 (9)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO$

*

Savannah Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

9 (217) 8 (61) 14 (55) 18 (8) 11 (6) 3 (6) 17 (8) 5 (5) 25 (9)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO$

*

* No speciated data for this bin 

The STN compositional charts show a much larger proportional contribution from organic matter 

compared to those for the IMPROVE sites, especially for the higher PM2.5 bins. This is in part 

due to differences between the IMPROVE and STN measurement techniques for organic 

carbon. Studies (e.g., EPA, 2004) have estimated the STN measurements to be as much as 30 

percent higher. Another reason for the higher organic contribution is that the STN sites are 

located in urban areas, which have higher organic carbon emissions. 

The relative contributions of the PM2.5 components vary by bin for each of the sites. The high 

PM2.5 concentration bins are distinguished from the lower concentration bins by higher sulfate 

and organic matter concentrations. With the higher values for organics, the dominant species 

ICF International 3-177 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 211
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-178 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

varies by bin, much more so than for the IMPROVE sites. Again, these variations are 

attributable to differences in meteorology as well as regional pollutant transport. 

Consider the two key high PM2.5 bins for Macon (Bins 19 and 14). We noted earlier, that more 

stable conditions and a greater potential for pollutant transport from Atlanta appear to drive the 

higher PM2.5 concentrations for Bin 14. This is manifested (Figure 3-8j) by higher average 

sulfate concentrations for this bin, compared to Bin 19. On average, Bin 19 is dominated by 

organic matter, while Bin 14 has a greater proportion of sulfate. 

Table 3-17 summarizes the characteristics for key Category 3 and 4 bins for the SEARCH 

monitoring sites. 

Table 3-17a. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for SEARCH Site Atlanta (Jefferson St.). 

The ranges in PM2.5 for Categories 3 and 4 are 27.5-35 and ≥ 35 μgm-3. 

Class 3 Class 4 

Bin 28 Bin 31 Bin 21 Bin 19 Bin 23 Bin 26 

PM2.5 Parameters 

Yesterday's FM at Atlanta (μg/m3) 31.3 30.9 33.4 37.7 34.9 43.4 

Yesterday's FM at Birmingham (μg/m3) 34.1 35.9 35.5 39.2 34.3 44.0 

Surface Meteorological Parameters 

Max. surface temperature (°C) 31.7 26.2 27.9 29.8 27.23 28.5 

Min. surface temperature (°C) 21.4 18.0 16.1 18.6 14.5 15.0 

Relative humidity (%) 74.2 70.7 66.0 69.9 61.8 65.1 

Surface wind speed (ms-1) 0.7 1.9 0.6 0.8 0.6 0.5 

Surface wind direction (degrees) 248 117 207 254 304 63 

Persistence 0.6 0.9 0.6 0.8 0.6 0.6 

Station pressure (mb) 987 990 990 988 989 991 

Rainfall (inches) 0.3 0.1 0 0.0 0.0 0 

Rain (# periods) 1.7 0.7 0 0.1 0.1 0 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 17.1 14.7 13.5 15.4 13.6 14.1 

Temperature PM 850 mb (°C) 17.6 13.8 14.9 16.3 15.7 14.8 

Stability at Atlanta (°C) 2.7 2.7 6.1 4.6 6.4 6.8 

Geopotential height difference 700 mb at Atlanta (m) -4.6 27.5 -10.8 6.4 -3.3 37.3 

Wind speed yesterday 700 mb at Atlanta (ms-1) 6.4 5.5 5.4 5.6 9.9 3.6 

Wind direction yesterday 700 mb at Atlanta (degrees) 326 259 31 9 326 0 

Wind speed yesterday 850 mb at Atlanta (ms-1) 3.6 5.2 5.2 2.4 6.8 4.9 

Wind speed AM 850 mb at Atlanta (ms-1) 5.3 6.8 3.4 3.5 7.1 3.5 

Wind speed PM 850 mb at Atlanta (ms-1) 4.7 6.6 3.4 6.7 4.8 3.7 

Wind direction yesterday 850 mb at Atlanta (degrees) 281 180 n/a 307 326 315 

Wind direction AM 850 mb at Atlanta (degrees) 306 166 90 288 315 45 

Wind direction PM 850 mb at Atlanta (degrees) 225 146 135 225 307 76 

Recirculation at Atlanta 0.1 0.1 0.2 0.4 0 0.2 

Cloud average 2.1 2.1 1.5 1.6 1.6 1.2 

Appendix B.7 - 212
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-179 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-17b. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for SEARCH Site Yorkville. 

The ranges in PM2.5 for Categories 3 and 4 are 22.5-30 and ≥ 30 μgm-3. 

Class 3 Class 4 

Bin 18 Bin 28 Bin 16 Bin 22 Bin 29 Bin 15 

PM2.5 Parameters 

Yesterday's FM at Atlanta (μg/m3) 25.5 35.5 26.3 38.0 39.9 27.1 

Yesterday's FM at Birmingham (μg/m3) 28.3 38.3 29.9 43.9 35.3 30.7 

Yesterday's FM at Yorkville (μg/m3) 22.2 28.7 22.7 35.4 31.8 21.5 

Surface Meteorological Parameters 

Max. surface temperature (°C) 28.5 28.2 23.2 28.6 26.6 28.6 

Min. surface temperature (°C) 18.1 17.6 18.1 18.4 17.2 18.6 

Relative humidity (%) 71.7 66.7 92.6 72.8 75.0 71.3 

Surface wind speed (ms-1) 2.0 2.7 1.7 1.2 2.6 1.8 

Surface wind direction (degrees) 99 243 180 243 90 108 

Persistence 0.8 0.9 0.6 0.7 1.0 0.7 

Station pressure (mb) 975 972 972 974 978 974 

Rainfall (inches) 0.1 0.1 0.1 0.0 0.1 0.1 

Rain (# periods) 0.6 0.5 2.0 0.1 0.9 1.2 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 15.0 15.2 13.9 15.3 13.4 15.3 

Temperature PM 850 mb (°C) 14.3 16.4 15.3 16.5 13.0 16.6 

Stability at Atlanta (°C) 2.5 6.6 -1.0 4.0 4.0 2.2 

Geopotential height difference 700 mb at Atlanta (m) -6.9 -6 -0.9 4.8 5.4 -1.6 

Wind speed yesterday 700 mb at Atlanta (ms-1) 5.1 4.9 7.4 5.7 4.5 6.0 

Wind direction yesterday 700 mb at Atlanta (degrees) 48 292 360 23 333 27 

Wind speed yesterday 850 mb at Atlanta (ms-1) 4.2 3.4 4.3 3.9 4.5 3.8 

Wind speed AM 850 mb at Atlanta (ms-1) 6.1 5.9 5.3 4.0 5.9 4.2 

Wind speed PM 850 mb at Atlanta (ms-1) 4.4 7.6 5.2 4.0 5.9 4.2 

Wind direction yesterday 850 mb at Atlanta (degrees) 98 249 315 22 117 297 

Wind direction AM 850 mb at Atlanta (degrees) 90 277 225 342 124 90 

Wind direction PM 850 mb at Atlanta (degrees) 112 254 0 56 124 135 

Recirculation at Atlanta 0.2 0.2 0.3 0.4 0 0.2 

Cloud average 1.7 1.7 2.5 1.7 2.0 1.8 

Appendix B.7 - 213
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-180 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-17c. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for SEARCH Site Birmingham. 

The ranges in PM2.5 for Categories 3 and 4 are 30-37.5 and ≥ 37.5 μgm-3. 

Class 3 Class 4 

Bin 10 Bin 14 Bin 25 Bin 20 Bin 24 

PM2.5 Parameters 

Yesterday's FM at Birmingham (μg/m3) 24.7 35.6 51.1 33.1 35.8 

Yesterday's FM at Atlanta (μg/m3) 21.1 27.8 39.3 23.5 25.5 

Yesterday's FM at Memphis (μg/m3) 18.8 21.9 27.8 18.2 20.8 

Yesterday's FM at Nashville (μg/m3) 16.8 21.2 28.9 18.7 17.9 

Surface Meteorological Parameters 

Max. surface temperature (°C) 28.6 28.5 28.7 23.7 30.4 

Min. surface temperature (°C) 12.8 15.8 14.0 10.2 15.9 

Relative humidity (%) 60.1 66.5 58.6 64.8 58.4 

Surface wind speed (ms-1) 0.6 0.5 0.5 0.5 0.7 

Surface wind direction (degrees) 360 342 344 27 180 

Persistence 0.6 0.5 0.7 0.6 0.7 

Station pressure (mb) 998 998 1000 1002 1000 

Rainfall (inches) 0.0 0.1 0.0 0.0 0.0 

Rain (# periods) 0.3 0.6 0.0 0.2 0.1 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 12.9 13.1 13.5 11.3 15.0 

Temperature PM 850 mb (°C) 13.7 14.5 14.1 12.3 15.9 

Stability at Birmingham (°C) 4.0 3.1 4.6 2.9 4.3 

Geopotential height difference 700 mb at Birmingham (m) 6.6 -2.9 0.8 -14.7 30.1 

Wind speed yesterday 700 mb at Birmingham (ms-1) 6.5 5.2 4.7 9.0 6.8 

Wind direction yesterday 700 mb at Birmingham (degrees) 310 292 354 63 338 

Wind speed yesterday 850 mb at Birmingham (ms-1) 4.2 2.7 2.9 7.0 2.8 

Wind speed AM 850 mb at Birmingham (ms-1) 5.1 4.9 3.7 6.1 4.2 

Wind speed PM 850 mb at Birmingham (ms-1) 4.3 4.8 2.9 4.9 3.7 

Wind direction yesterday 850 mb at Birmingham (degrees) 360 254 37 27 90 

Wind direction AM 850 mb at Birmingham (degrees) 270 243 270 180 270 

Wind direction PM 850 mb at Birmingham (degrees) 34 220 360 207 243 

Recirculation at Birmingham 0.2 0.3 0.5 0.0 0.4 

Cloud average 1.3 1.7 1.4 1.6 1.6 

Appendix B.7 - 214
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-181 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-17d. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for SEARCH Site Centreville. 

The ranges in PM2.5 for Categories 3 and 4 are 22.5-30 and ≥ 30 μgm-3. 

Class 3 Class 4 

Bin 16 Bin 20 Bin 19 Bin 28 Bin 18 Bin 21 

PM2.5 Parameters 

Yesterday's FM at Birmingham (μg/m3) 34.6 33.6 32.8 51.5 25.3 38.6 

Yesterday's FM at Atlanta (μg/m3) 28.1 33.1 31.1 38.1 18.5 30.0 

Yesterday's FM at Centreville (μg/m3) 24.7 24.6 26.7 38.3 24.3 27.9 

Surface Meteorological Parameters 

Max. surface temperature (°C) 31.2 31.7 32.9 31.0 25.4 35.4 

Min. surface temperature (°C) 20.4 20.3 22.8 19.8 13.5 23.7 

Relative humidity (%) 70.8 21.9 70.0 67.6 68.0 71.6 

Surface wind speed (ms-1) 1.4 0.9 3.0 1.0 1.2 1.0 

Surface wind direction (degrees) 330 110 304 349 329 153 

Persistence 0.7 0.6 1.0 0.7 0.6 0.6 

Station pressure (mb) 1003 1004 997 1005 1003 1005 

Rainfall (inches) 0.0 0.0 0.0 0.1 0.1 0.0 

Rain (# periods) 0.3 0.4 0.2 0.1 0.6 0.2 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 15.5 15.8 18.2 15.2 12.4 18.0 

Temperature PM 850 mb (°C) 16.2 17.1 17.9 15.9 11.3 20.1 

Stability at Birmingham (°C) 1.6 2 -1.4 2.6 1.7 3.4 

Geopotential height difference 700 mb at Birmingham (m) -4.1 -0.2 -19.8 -0.3 15.1 10.3 

Wind speed yesterday 700 mb at Birmingham (ms-1) 5.9 5.6 9.3 4.9 12.3 5.2 

Wind direction yesterday 700 mb at Birmingham (degrees) 342 56 27 6 297 360 

Wind speed yesterday 850 mb at Birmingham (ms-1) 4.6 3.6 5.6 3.7 6.1 2.6 

Wind speed AM 850 mb at Birmingham (ms-1) 5.0 3.3 11.0 3.5 8.2 4.6 

Wind speed PM 850 mb at Birmingham (ms-1) 4.5 2.6 7.1 2.9 4.7 2.7 

Wind direction yesterday 850 mb at Birmingham (degrees) 360 27 14 23 11 n/a 

Wind direction AM 850 mb at Birmingham (degrees) 309 202 360 243 270 315 

Wind direction PM 850 mb at Birmingham (degrees) 356 117 346 45 360 270 

Recirculation at Birmingham 0.3 0.4 0 0.4 0 0.3 

Cloud average 1.8 1.6 1.6 1.9 1.8 1.7 

Appendix B.7 - 215
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-182 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-17e. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for SEARCH Site Pensacola. 

The ranges in PM2.5 for Categories 3 and 4 are 22.5-27.5 and ≥ 27.5 μgm-3. 

Class 3 Class 4 

Bin 22 Bin 31 Bin 19 Bin 27 Bin 18 

PM2.5 Parameters 

Yesterday's FM at Gulfport (μg/m3) 19.4 24.2 18.2 25.0 16.9 

Yesterday's FM at Pensacola (μg/m3) 22.7 30.8 19.5 30.7 20.1 

Yesterday's FM at New Orleans/Baton Rouge (μg/m3) 21.3 26.7 18.7 25.3 19.1 

Surface Meteorological Parameters 

Max. surface temperature (°C) 25.2 24.9 25.3 28.0 24.2 

Min. surface temperature (°C) 13.1 16.1 14.6 18.7 10.6 

Relative humidity (%) 70.4 85.8 73.5 74.1 64.1 

Surface wind speed (ms-1) 1.6 0.6 0.5 0.7 0.6 

Surface wind direction (degrees) 90 72 153 169 360 

Persistence 0.9 0.7 0.4 0.6 0.7 

Station pressure (mb) 1019 1019 1022 1018 1024 

Rainfall (inches) 0.0 0.1 0.0 0.0 0.0 

Rain (# periods) 0.0 0.7 0.1 0.2 0.0 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 11.8 14.0 12.5 14.3 10.4 

Temperature PM 850 mb (°C) 12.0 14.0 13.0 14.8 11.3 

Stability at Tallahassee (°C) 2.3 1.9 2.4 1.5 6.2 

Geopotential height difference 700 mb at Tallahassee (m) -7.5 11 23.1 0.6 -2.8 

Wind speed yesterday 700 mb at Slidell (ms-1) 8.0 6.4 5.7 4.7 7.5 

Wind speed yesterday 700 mb at Tallahassee (ms-1) 7.8 6.7 9.1 7.2 7.5 

Wind speed yesterday 700 mb at Birmingham (ms-1) 8.9 9.8 9.9 6.8 10.2 

Wind direction yesterday 700 mb at Slidell (degrees) 90 270 297 328 315 

Wind direction yesterday 700 mb at Tallahassee (degrees) 315 90 338 309 288 

Wind direction yesterday 700 mb at Birmingham (degrees) 284 292 323 310 288 

Wind speed yesterday 850 mb at Slidell (ms-1) 7.7 5.8 5.1 3.9 4.6 

Wind speed yesterday 850 mb at Tallahassee (ms-1) 5.0 5.4 3.0 4.6 5.7 

Wind speed yesterday 850 mb at Birmingham (ms-1) 6.4 6.0 5.3 4.2 6.1 

Wind speed AM 850 mb at Slidell (ms-1) 8.1 5.9 3.5 4.3 4.8 

Wind speed AM 850 mb at Tallahassee (ms-1) 7.0 5.6 4.2 4.8 4.3 

Wind speed AM 850 mb at Birmingham (ms-1) 8.5 7.1 5.9 4.1 6.1 

Wind speed PM 850 mb at Slidell (ms-1) 8.1 4.9 4.0 4.3 5.1 

Wind speed PM 850 mb at Tallahassee (ms-1) 7.2 6.1 4.0 5.6 4.5 

Wind speed PM 850 mb at Birmingham (ms-1) 8.4 8.0 5.4 4.6 5.0 

Wind direction yesterday 850 mb at Slidell (degrees) 360 180 346 360 333 

Wind direction yesterday 850 mb at Tallahassee (degrees) 360 360 360 339 360 

Wind direction yesterday 850 mb at Birmingham (degrees) 270 207 304 342 315 

Wind direction AM 850 mb at Slidell (degrees) 207 194 207 214 342 

Wind direction AM 850 mb at Tallahassee (degrees) 270 207 333 270 288 

Wind direction AM 850 mb at Birmingham (degrees) 284 214 315 282 360 

Wind direction PM 850 mb at Slidell (degrees) 297 198 360 22 360 

Wind direction PM 850 mb at Tallahassee (degrees) 45 270 63 328 342 

Wind direction PM 850 mb at Birmingham (degrees) 270 225 315 270 333 

Cloud average 1.4 1.9 1.3 1.8 1.5 

Appendix B.7 - 216
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-183 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-17f. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for SEARCH Site Outlying Landing Field (OLF). 

The ranges in PM2.5 for Categories 3 and 4 are 20-27.5 and ≥ 27.5 μgm-3. 

Class 3 Class 4 

Bin 25 Bin 13 Bin 28 

PM2.5 Parameters 

Yesterday's FM at Gulfport (μg/m3) 19.9 17.2 28.3 

Yesterday's FM at Pensacola (μg/m3) 23.9 21.4 31.5 

Yesterday's FM at Outer Landing Field (μg/m3) 21.1 16.2 33.8 

Yesterday's FM at New Orleans/Baton Rouge (μg/m3) 21.9 20.3 27.0 

Surface Meteorological Parameters 

Max. surface temperature (°C) 31.0 25.3 30.6 

Min. surface temperature (°C) 18.5 11.0 18.9 

Relative humidity (%) 67.5 59.1 73.3 

Surface wind speed (ms-1) 1.6 1.1 1.0 

Surface wind direction (degrees) 270 342 286 

Persistence 0.7 0.6 0.6 

Station pressure (mb) 1014 1016 1013 

Rainfall (inches) 0.0 0.0 0.0 

Rain (# periods) 0.2 0.1 0.4 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 15.4 11.7 15.6 

Temperature PM 850 mb (°C) 16.3 12.0 16.0 

Stability at Tallahassee (°C) 1.2 3.9 -0.4 

Geopotential height difference 700 mb at Tallahassee (m) 3.1 1.6 5.3 

Wind speed yesterday 700 mb at Slidell (ms-1) 4.8 6.1 4.9 

Wind speed yesterday 700 mb at Tallahassee (ms-1) 7.5 8.4 6.9 

Wind speed yesterday 700 mb at Birmingham (ms-1) 7.8 7.5 5.8 

Wind direction yesterday 700 mb at Slidell (degrees) 4 360 330 

Wind direction yesterday 700 mb at Tallahassee (degrees) 336 342 311 

Wind direction yesterday 700 mb at Birmingham (degrees) 315 352 319 

Wind speed yesterday 850 mb at Slidell (ms-1) 4.8 7.0 4.0 

Wind speed yesterday 850 mb at Tallahassee (ms-1) 5.5 4.1 4.6 

Wind speed yesterday 850 mb at Birmingham (ms-1) 6.0 5.4 5.6 

Wind speed AM 850 mb at Slidell (ms-1) 4.7 5.8 3.9 

Wind speed AM 850 mb at Tallahassee (ms-1) 5.3 6.0 5.2 

Wind speed AM 850 mb at Birmingham (ms-1) 6.7 6.2 3.4 

Wind speed PM 850 mb at Slidell (ms-1) 5.7 5.9 3.6 

Wind speed PM 850 mb at Tallahassee (ms-1) 5.4 5.8 5.3 

Wind speed PM 850 mb at Birmingham (ms-1) 6.0 5.1 3.0 

Wind direction yesterday 850 mb at Slidell (degrees) 25 11 22 

Wind direction yesterday 850 mb at Tallahassee (degrees) 352 360 325 

Wind direction yesterday 850 mb at Birmingham (degrees) 320 352 333 

Wind direction AM 850 mb at Slidell (degrees) 180 90 135 

Wind direction AM 850 mb at Tallahassee (degrees) 319 346 243 

Wind direction AM 850 mb at Birmingham (degrees) 270 326 279 

Wind direction PM 850 mb at Slidell (degrees) 8 63 48 

Wind direction PM 850 mb at Tallahassee (degrees) 347 34 352 

Wind direction PM 850 mb at Birmingham (degrees) 320 360 225 

Cloud average 1.6 1.1 1.8 

Appendix B.7 - 217
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-184 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-17g. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for SEARCH Site Gulfport. 

The ranges in PM2.5 for Categories 3 and 4 are 20-25 and ≥ 25 μgm-3. 

Class 3 Class 4 

Bin 29 Bin 12 Bin 10 Bin 30 Bin 16 

PM2.5 Parameters 

Yesterday's FM at Gulfport (μg/m3) 24.3 25.5 17.7 28.1 16.7 

Yesterday's FM at Pensacola (μg/m3) 20.0 18.0 21.7 29.9 16.9 

Yesterday's FM at New Orleans/Baton Rouge (μg/m3) 26.1 18.3 18.1 28.4 22.1 

Surface Meteorological Parameters 

Max. surface temperature (°C) 26.1 23.4 31.7 29.4 27.4 

Min. surface temperature (°C) 6.1 9.6 21.3 19.4 16.7 

Relative humidity (%) 77.9 69.7 73.9 73.3 67.9 

Surface wind speed (ms-1) 1.4 1.0 1.2 1.0 0.7 

Surface wind direction (degrees) 158 191 194 220 225 

Persistence 0.7 0.5 0.6 0.5 0.4 

Station pressure (mb) 1018 1019 1017 1017 1018 

Rainfall (inches) 0.1 0.0 0.0 0.0 0.0 

Rain (# periods) 0.5 0.1 0.3 0.3 0.1 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 12.5 11.1 16.2 14.2 13.2 

Temperature PM 850 mb (°C) 12.5 11.5 16.7 14.9 14.0 

Stability at Slidell (°C) 1.7 7.0 -0.1 0.7 2.3 

Geopotential height difference 700 mb at Slidell (m) -1.2 9.3 5.0 1.6 -6.7 

Wind speed yesterday 700 mb at Jacksonville (ms-1) 7.6 8.1 6.8 6.0 9.0 

Wind speed yesterday 700 mb at Slidell (ms-1) 4.6 6.2 5.7 5.5 8.8 

Wind direction yesterday 700 mb at Jacksonville (degrees) 279 320 281 330 297 

Wind direction yesterday 700 mb at Slidell (degrees) 297 342 360 353 297 

Wind speed yesterday 850 mb at Jacksonville (ms-1) 6.3 6.4 3.6 4.2 5.9 

Wind speed yesterday 850 mb at Slidell (ms-1) 4.6 6.2 5.7 4.4 8.0 

Wind speed AM 850 mb at Jacksonville (ms-1) 6.7 4.9 5.8 4.4 7.3 

Wind speed AM 850 mb at Slidell (ms-1) 5.2 5.0 5.0 4.0 6.1 

Wind speed PM 850 mb at Jacksonville (ms-1) 6.3 6.4 3.6 4.7 5.1 

Wind speed PM 850 mb at Slidell (ms-1) 5.2 5.6 4.8 4.3 5.1 

Wind direction yesterday 850 mb at Jacksonville (degrees) 270 360 n/a 9 342 

Wind direction yesterday 850 mb at Slidell (degrees) 351 6 90 21 360 

Wind direction AM 850 mb at Jacksonville (degrees) 262 262 169 243 304 

Wind direction AM 850 mb at Slidell (degrees) 180 243 121 149 360 

Wind direction PM 850 mb at Jacksonville (degrees) 217 211 166 225 297 

Wind direction PM 850 mb at Slidell (degrees) 270 236 90 29 360 

Recirculation at Slidell 0.3 0.2 360 0.2 0.0 

Cloud average 1.7 1.2 1.7 1.6 1.6 

Appendix B.7 - 218
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

ICF International 3-185 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Table 3-17h. Summary of Average Input Parameters for Key Bins for CART Classification 

Categories 3 and 4: PM2.5 CART Analysis for SEARCH Site Oak Grove. 

The ranges in PM2.5 for Categories 3 and 4 are 20-27.5 and ≥ 27.5 μgm-3. 

Class 3 Class 4 

Bin 19 Bin 29 Bin 14 Bin 31 Bin 26 

PM2.5 Parameters 

Yesterday's FM at Gulfport (μg/m3) 19.4 23.8 14.7 26.0 22.3 

Yesterday's FM at Oak Grove (μg/m3) 19.7 22.9 17.1 35.0 22.8 

Yesterday's FM at Pensacola (μg/m3) 18.6 28.6 17.1 24.6 30.73 

Yesterday's FM at New Orleans/Baton Rouge (μg/m3) 23.8 22.9 16.8 29.3 26.4 

Surface Meteorological Parameters 

Max. surface temperature (°C) 28.6 33.0 29.3 28.7 25.5 

Min. surface temperature (°C) 16.2 20.1 14.4 17.2 14.3 

Relative humidity (%) 65.2 71.2 62.4 67.6 65.8 

Surface wind speed (ms-1) 1.0 1.2 1.4 1.1 1.2 

Surface wind direction (degrees) 75 180 360 321 76 

Persistence 0.7 0.8 0.8 0.7 0.8 

Station pressure (mb) 1012 1010 1011 1010 1011 

Rainfall (inches) 0.0 0.0 0.0 0.0 0.0 

Rain (# periods) 0.2 0.12 0.1 0.2 0.5 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 14.0 17.0 14.6 13.7 11.7 

Temperature PM 850 mb (°C) 13.6 18.0 15.4 14.7 12.3 

Stability at Slidell (°C) 1.1 0.0 2.7 1.6 0.9 

Geopotential height difference 700 mb at Slidell (m) -0.1 4.0 3.7 5.6 6.4 

Wind speed yesterday 700 mb at Jacksonville (ms-1) 6.3 5.2 7.9 9.0 5.1 

Wind speed yesterday 700 mb at Slidell (ms-1) 5.9 4.9 7.1 7 6.4 

Wind direction yesterday 700 mb at Jacksonville (degrees) 323 8 315 297 270 

Wind direction yesterday 700 mb at Slidell (degrees) 329 27 329 328 309 

Wind speed yesterday 850 mb at Jacksonville (ms-1) 4.8 4.4 4.2 4.7 3.9 

Wind speed yesterday 850 mb at Slidell (ms-1) 5.4 4.4 6.3 4.8 4.5 

Wind speed AM 850 mb at Jacksonville (ms-1) 5.1 4.7 4.0 6.5 4.5 

Wind speed AM 850 mb at Slidell (ms-1) 4.6 3.9 4.3 4.5 5.4 

Wind speed PM 850 mb at Jacksonville (ms-1) 4.8 4.4 5.5 5.0 6.6 

Wind speed PM 850 mb at Slidell (ms-1) 5.7 4.3 5.0 4.5 5.7 

Wind direction yesterday 850 mb at Jacksonville (degrees) 90 342 315 307 270 

Wind direction yesterday 850 mb at Slidell (degrees) 48 23 14 0 333 

Wind direction AM 850 mb at Jacksonville (degrees) 194 270 326 275 207 

Wind direction AM 850 mb at Slidell (degrees) 243 90 45 278 198 

Wind direction PM 850 mb at Jacksonville (degrees) 149 284 146 304 153 

Wind direction PM 850 mb at Slidell (degrees) 52 63 56 10 27 

Recirculation at Slidell 0.2 0.3 0 0.4 0.2 

Cloud average 1.7 1.7 1.6 1.7 1.8 

Appendix B.7 - 219
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

For Atlanta, the PM2.5 concentration ranges for Categories 3 and 4 are 30 to 37.5 and greater 

than or equal to 37.5 μgm-3, respectively. There are three Category 3 and three Category 4 bins 

that meet the criteria for key bins. The Category 4 bins tend to have lower average relative 

humidity, greater stability, and higher prior-day PM2.5 concentrations, than the Category 3 bins, 

but many of the characteristics are similar between the two groups of bins. The Category 4 bins 

are characterized by very low surface wind speeds. Surface wind directions are from the 

southwest (Bin 19), northwest (Bin 23), and northeast (Bin 26). Two of the Category 4 bins have 

cooler minimum temperatures than the other key bins and greater stability. This same tendency 

is reflected in the wind directions aloft. In contrast, southeasterly wind components are 

associated with the two of the Category 3 bins. CART appears to have identified three distinct 

high PM2.5 concentration regimes. 

For Birmingham, the PM2.5 concentration ranges for Categories 3 and 4 are 30 to 37.5 and 

greater than or equal to 37.5 μgm-3, respectively. There are two Category 3 and three Category 

4 bins that meet the criteria for key bins. All of the key bins are characterized by very low 

surface wind speeds. Two of the three Category 4 bins are distinguished from the Category 3 

bins by lower average relative humidity. The third bin is distinguished from the Category 3 bins 

and all other key bins by lower temperatures. Bin 25 (Category 4) is very similar to Bin 10 

(Category 3), in terms of the average parameter values, with the exception of the prior-day PM 

concentration for Birmingham. A much higher prior-day value for Bin 25 likely contributes to the 

higher PM2.5 values and higher category designation. Bins 20 and 24 are differentiated by wind 

directions. Surface winds are northeasterly for Bin 20 and southerly for Bin 24, compared to 

northwesterly for Bin 25 and the key Category 3 bins. Upper-level winds are southerly to 

southwesterly for Bin 20 and (more typically) westerly to southwesterly for Bin 24. 

Figure 3-9 shows the average composition for all key PM2.5 bins for each of the SEARCH sites. 

Figure 3-9a. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: SEARCH Site 

Atlanta. 

Atlanta SEARCH Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

1 (751) 7 (146) 4 (116) 8 (43) 5 (39) 3 (33) 28 (15) 31 (12) 21 (16) 19 (18) 23 (7) 26 (5)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-186 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 220
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-9b. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: SEARCH Site 

Yorkville. 

Yorkville SEARCH Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

1 (793) 2 (204) 20 (47) 5 (62) 11 (40) 8 (26) 18 (18) 28 (13) 6 (14) 22 (23) 29 (7) 15 (6)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure 3-9c. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: SEARCH Site 

Birmingham. 

Birmingham SEARCH Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

5 (568) 9 (213) 27 (137) 4 (53) 31 (47) 28 (24) 10 (22) 14 (29) 25 (24) 20 (9) 24 (7)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-187 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 221
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-9d. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: SEARCH Site 

Centreville. 

Centreville SEARCH Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

1 (672) 3 (115) 2 (112) 10 (80) 7 (45) 24 (33) 16 (34) 20 (19) 9 (9) 28 (16) 18 (8) 21 (6)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure 3-9e. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: SEARCH Site 

Pensacola. 

Pensacola SEARCH Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

1 (581) 3 (8) 2 (1) 10 (1) 7 (1) 24 (2) 16 (4) 20 (13) 9 (1) 28 (2) 18 (6)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-188 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 222
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-9f. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: SEARCH Site 

Outlying Landing Field. 

Outlying Landing Field SEARCH Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

1 (650) 2 (195) 23 (98) 16 (100) 24 (27) 9 (35) 25 (32) 13 (12) 28 (33)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure 3-9g. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: SEARCH Site 

Gulfport. 

Gulfport SEARCH Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

1 (689) 2 (193) 27 (83) 25 (49) 9 (44) 8 (30) 29 (17) 12 (18) 10 (10) 30 (40) 16 (7)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

ICF International 3-189 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 223
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Examination of Relationships between Meteorological and Air Quality Data Using 

Classification and Regression Tree (CART) Analysis 

Figure 3-9h. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: SEARCH Site 

Oak Grove. 

Oak Grove SEARCH Key PM Bins: Component Averages

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

1 (668) 7 (106) 8 (88) 22 (78) 3 (71) 9 (38) 19 (26) 29 (25) 14 (12) 31 (21) 26 (11)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

The compositional charts for the PM2.5 for the SEARCH sites also show a much larger 

proportional contribution from organics than the IMPROVE charts, especially for the higher 

PM2.5 bins. The relative ranking of the species contributions is similar to that for the STN sites. A 

comparison of the compositional averages for Birmingham using the STN (Figure 3-8a) and 

SEARCH (Figure 3-9c) data, shows that the organic matter and overall PM2.5 values are higher 

in the STN data, but that the tendency for organic matter to be the dominant species appears in 

both sets of results. 

The compositional analysis results for Birmingham (Figure 3-9c) also show a higher contribution 

of elemental carbon than for most other sites, and this may be related to emissions from the 

steel industry facilities that are located in Birmingham. 

For all three of the key Category 4 PM2.5 bins for Birmingham (Bins 25, 20, and 24), organic 

matter is the dominant species. However, the relative proportion of the species concentrations is 

different for each bin. This may be due to the differences in the average wind directions. All of 

the key bins are characterized by very low surface wind speeds, but, on average, the days 

within the bins have different wind directions. Surface winds are northwesterly for Bin 24, 

northeasterly for Bin 20, and southerly for Bin 24. We noted earlier that Bin 25 (Category 4) is 

very similar to Bin 10 (Category 3), in terms of the average parameter values, with the exception 

of the prior-day PM concentration for Birmingham. The two bins have similar species 

distributions, and the higher values for Bin 24 are due to slight increases in sulfate and organic 

matter and a greater increase in elemental carbon. 

ICF International 3-190 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 224
4. Meteorological Representativeness and Episode 

Selection Exercises 

The CART results and a meteorological characterization and episode selection tool, based on 

these results, were used to provide information related to the representativeness of the model 

year 2002 and the periods selected by VISTAS for model performance evaluation and 

preliminary sensitivity testing, relative to the five-year regional haze baseline period. The CART 

results and tool were also used in selecting subset periods of 2002 for PM2.5 modeling and 

sensitivity analysis, and in the calculation of weighting factors related to regional haze and PM2.5

for the modeled days. These exercises are described in this section. A comparison of the results 

for Birmingham using the STN and SEARCH datasets is provided in the appendix. 

4.1. Meteorological Characterization and Episode Selection Tool 

In this study, the CART results served as the basis for developing a tool capable of addressing 

questions regarding the representativeness of selected episodic and annual simulation periods as 

well as the selection of discrete multi-day periods for refined modeling or control-strategy 

evaluation. The CART results (groupings of days with similar characteristics) were coupled with 

characterization and episode selection algorithms in order to provide this information. The VISTAS 

meteorological characterization tool is available in electronic format. 

For any input set of days, the characterization algorithm assesses and summarizes the range, 

type, and frequency of sampling of the CART bins; the degree to which key characteristics 

(CART bins) are represented; mean values for all parameters, including chemical speciation; 

representation of the days comprising the regional metrics, and ability to represent the regional 

haze metrics or PM2.5 annual average or design values (estimated using error statistics) for one 

or more sites selected by the user. A summary of the meteorological parameters for the 

selected days is also optionally provided, together with an assessment of whether or not the 

conditions are typical of the full analysis period. 

The episode selection algorithm, based on the EPISODES program that we originally developed 

for SAMI, identifies episodes characterized by typical (frequently occurring) meteorological 

conditions and representative of the multi-year visibility and PM2.5 metrics. The selection of days 

is guided by user-input episode selection criteria pertaining to the number of days, 

contiguousness and length of episode periods, and error tolerance in representing the regional 

haze metrics. The days identified by the episode selection algorithm can then be summarized 

using the characterization algorithm. 

Figure 4-1 diagrams the VISTAS meteorological characterization and episode selection tool. 

ICF International 4-1 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 225
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Meteorological Representativeness and Episode Selection Exercises 

Figure 4-1. Schematic Diagram of the VISTAS Meteorological Characterization 

and Episode Selection Tool. 

PM Data (IMPROVE, STN, 

and SEARCH) Visibility Meteorological Data

CART

CART classification 

algorithm/variable importance Conceptual model for visibility 

(and, optionally, PM2.5) Classification category and 

bin characteristics

06 

Together the CART results and the meteorological characterization and episode selection tool were 

used to provide information related to the representativeness of the model year 2002 and the 

periods selected by VISTAS for model performance evaluation and preliminary sensitivity testing. 

used to provide information related to the representativeness of the model year 2002 and the 

4.1.1. Meteorological Characterization Component 

In the characterization mode, the user inputs a date or series of dates and the tool provides 

information about those dates. 

The user must select the type of analysis (visibility or PM2.5) by selecting the appropriate button. 

He/she may also select the meteorology option by checking that box. He/she must also select the 

desired site(s) and either enter the dates manually or read them in from an external file by clicking 

on the “Read Dates” button. The tool will accept any dates included in the analysis period, which 

currently includes the years 2000-2004. The dates must be in yymmdd format. The initial input 

screen for an example application for PM2.5 for the STN sites and the Atlanta, Birmingham, 

Gulfport, and Pensacola SEARCH sites for 3 June – 10 July 2002 is displayed in Figure 4-2. 

The user must select the type of analysis (visibility or PM2.5) by selecting the appropriate button. 

He/she may also select the meteorology option by checking that box. He/she must also select the 

desired site(s) and either enter the dates manually or read them in from an external file by clicking 

on the “Read Dates” button. The tool will accept any dates included in the analysis period, which 

currently includes the years 2000-2004. The dates must be in yymmdd format. The initial input 

screen for an example application for PM2.5 for the STN sites and the Atlanta, Birmingham, 

Gulfport, and Pensacola SEARCH sites for 3 June – 10 July 2002 is displayed in Figure 4-2. 

EPISODES

CART Results

CHARACTERIZATION 

ALGORITHM

Alternate/subset 

modeling periods

Summary of characteristics, 

representativeness, and error statistics

Conceptual 

Description

Meteorological Characterization Episode Selection

User-specified 

episode 

selection 

User-specified parameters dates/periods 

of interest

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Figure 4-2. Initial Input Screen for the Characterization Portion of the VISTAS 

Meteorological Characterization Tool: Example for PM2.5 for all STN Sites Plus the Atlanta, 

Birmingham, Gulfport, and Pensacola SEARCH Sites, for 6/3/02-7/10/02. 

Once the dates are entered, the user must select from among the Visibility Metrics, PM2.5 

Metrics, or Meteorological Metrics buttons to obtain the results. For both visibility and PM, key 

metrics summarize how well the days represent: 

• Frequently occurring meteorological conditions, as identified by CART 

– Number and type of key1

 bins represented. 

– Percent of key bins represented within each classification category. 

– Distribution of days within the key bins, relative to the full analysis period. 

– Distribution of days within all bins, relative to the full analysis period. 

For visibility, the output also includes the following regional haze metrics, where the 20 percent 

worst and best days are defined, respectively, as the 20 percent haziest and 20 percent clearest 

days in the 2000-2004 baseline period: 

• Mean extinction coefficient, calculated using a CART-based frequency weighting of the days. 

The average is calculated in this manner so that it can be compared with annual mean 

 

1 Key bins for each category are those containing the greatest number of correctly classified days. Approximately three key bins 

were selected for each classification category for each site. 

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extinction coefficient values and to determine whether the extinction coefficients for the 

selected subset of days are representative of a selected or typical annual period. 

• Range of extinction coefficient. 

• Quarterly distribution relative to the 20 percent best and worst days. 

• Dates of the selected days that are also among the 20 percent best and worst days. 

• Chemical composition and ranking of contributors to extinction coefficient and PM2.5.

For PM, the output also includes the following PM2.5 metrics: 

• PM2.5 design value 

• Range of PM2.5 concentrations. 

• Annual average PM2.5 concentration, calculated using a CART-based frequency weighting of 

the days. The average is calculated in this manner so that it can be compared with annual 

average concentrations, including those that comprise the design value. The objective is to 

determine whether the concentrations for the selected subset of days are representative of a 

selected or typical annual period. 

• Quarterly distribution relative to the 20 percent best and worst days. 

• Chemical composition and ranking of contributors to PM2.5.

An example result for PM2.5 is given in Figure 4-3. 

Figure 4-3. Example Characterization Result Screen for PM2.5. 

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For meteorology, the output includes the bin and CART category into which each date falls as well 

as the maximum temperature, relative humidity, wind speed and direction, and precipitation on 

that date. It also includes the number and percent of the selected days that have atypical 

meteorological conditions. 

There are also several options for graphical display of the results (these are obtained by clicking 

on the miniature bar charts next to the metric descriptors). 

The characterization tool was used during the course of the project to examine the representativeness 

of the two episode periods selected for air quality model performance evaluation, and to refine the 

selection of the two episode periods that were used for model sensitivity analysis. 

4.1.2. Episode Selection Component 

In the episode selection mode, the user specifies criteria for episode selection (such as total 

number of days, sites to optimize over, relative importance of various control factors, etc.) and 

the analytic tool provides a list of episode dates. These dates can subsequently be input to the 

characterization scheme to obtain information about the episodes. 

The user must select the type of analysis (visibility or PM2.5), by selecting the appropriate button, 

and select the number (up to 8) and name(s) of the sites from two drop-down menus. He/she may 

enter the desired number of days (the default is 40), and check a box if he/she wishes to use only 

properly classified days. The user may also enter values for other control factors, including a 

distance factor, chain factor, and season factor. The relative values of these factors (and not the 

absolute values) guide the episode selection and specify the relative importance of 1) representing 

annual average values of visibility (or PM2.5), 2) including consecutive days, and 3) representing all 

seasons in the episode selection results. The distance factor determines the relative emphasis on 

selecting days (combined) that represent the weighted annual average value of extinction coefficient 

or PM2.5 (whichever is selected) and thus the key bins. The chain factor determines the degree to 

which consecutive days are sought. The season factor weights the degree to which the different 

seasons are represented by the selected dates. Finally, the user may check a box if he/she wishes 

to consider only days from particular classification categories. If so, he/she then has the opportunity 

to select those categories from a menu. The initial input screen for an example application for PM2.5

for the Atlanta SEARCH site is displayed in Figure 4-4. 

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Figure 4-4. Initial Input Screen for the Episode Selection Portion of the VISTAS Meteorological 

Characterization Tool: Example for PM2.5 for Atlanta. 

Once the inputs are entered, the Run button is selected and the results screen appears. This 

summarizes the total number of episodes (defined by contiguous days), combined error 

summary for all selected sites, and site-specific errors. The errors summarize how well the 

selected episodes represent annual average values. The combined-site errors include an 

average error (the average difference in extinction coefficient or concentration), optimized cost 

(a relative measure of how well the distance, chain and season criteria are met), and average 

biased error (biased or signed error, averaged over all sites). The site-specific errors include the 

distance error (which quantifies the representation of the annual average value of the 

parameter, scaled to compensate for bins that are not represented) and the biased error (same 

as the distance error but not scaled to account for missing bins). By clicking on the Save Output

button, the user can save and open/view a file containing the episode dates. An example results 

screen is shown in Figure 4-5. 

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Figure 4-5. Example Episode Selection Result Screen for PM2.5. 

There is also an option for graphical display of the results (obtained by clicking on the miniature 

bar chart). 

The episode selection component of the tool was used to guide the selection of the two episode 

periods that were used by VISTAS for model sensitivity analysis. 

4.2. Analysis of the Representativeness of the 2002 Simulation 

Period 

The CART results and meteorological characterization tool were used to explore several 

questions related to modeling episode period representativeness. As noted earlier, the key 

question is: How representative is the year 2002, as selected for VISTAS atmospheric 

modeling, considering meteorology, fine particulate, and visibility, relative to the full baseline 

period. The characteristics of the 2000-2004 baseline period and each individual year 

comprising that period are examined and compared in this section. 

4.2.1. IMPROVE Sites 

Table 4-1 summarizes and compares 2000-2004, and each individual year within this period for 

the IMPROVE sites. The summary metrics included in this table are the weighted average 

extinction coefficient, weighted average PM2.5 concentration, range in PM2.5 concentration, 

percentage of key visibility bins represented (considering all classes), the relative distribution of 

days among the key visibility bins for all categories (distribution error), percentage of key PM2.5

bins represented (considering all classes), and the relative distribution of days among the key 

PM2.5 bins for all categories (distribution error). These terms are explained in more detail, in the 

discussion following Table 4-1. 

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Table 4-1. Summary of Visibility, PM2.5, and Meteorological Characteristics for the 2000-2004 

Analysis Period: IMPROVE Sites. 

(a) Breton 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 78.5 7.6 1.2 – 21.5 100 

2000 92.5 9.4 4.3 – 17.2 100 1.9 100 2.9 

2001 78.3 7.7 2.2 – 20.3 100 1.3 100 1.4 

2002 71.2 6.7 1.8 – 16.4 100 1.6 100 0.7 

2003 79.5 7.6 1.7 – 19.7 100 0.9 100 0.9 

2004 80.5 7.9 1.2 – 21.5 100 1.3 100 1.3 

 (b) Brigantine 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 95.6 9.7 1.4 – 39.2 

 

2000 100.2 10.1 1.5 – 27.3 100 0.9 100 0.8 

2001 86.1 9.3 2.6 – 30.1 100 1.3 100 2.1 

2002 93.6 9.6 1.4 – 36.5 100 0.9 100 1.7 

2003 96.7 9.8 1.8 – 39.2 100 1.7 100 1.1 

2004 92.5 9.6 3.0 – 28.6 100 1.3 100 1.6 

(c) Cadiz 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 107.4 11.0 0.6 – 31.3 

2000 NA NA NA NA NA NA NA 

2001 100.4 10.9 0.6 – 27.1 100 1.7 100 1.6 

2002 107.4 11.1 4.1 – 30.2 100 1.1 100 1.0 

2003 111.4 11.1 3.0 – 31.1 100 1.3 100 0.5 

2004 105.3 11.1 2.2 – 26.5 100 1.1 100 1.5 

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 (d) Caney Creek 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 83.0 9.0 0.3 – 28.3 

2000 85.8 9.0 0.3 – 22.4 100 1.6 100 1.7 

2001 79.1 9.3 0.9 – 21.6 100 1.0 100 1.4 

2002 92.1 8.9 0.5 – 28.3 100 0.9 100 1.0 

2003 87.5 8.8 1.5 – 25.1 100 1.0 100 1.2 

2004 80.9 8.6 0.4 – 19.0 100 1.2 100 1.3 

(e) Cape Romain 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 82.0 8.6 1.1 – 30.1 

2000 90.5 9.4 2.7 – 24.9 100 1.2 100 2.2 

2001 77.2 8.6 2.0 – 21.9 100 0.5 100 1.0 

2002 79.8 8.0 1.1 – 22.6 100 1.3 100 1.1 

2003 74.0 8.0 1.5 – 18.5 100 1.0 100 1.1 

2004 88.7 8.7 1.3 – 30.1 100 0.8 100 1.1 

(f) Chassahowitzka 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 89.5 8.7 2.1 – 24.7 

2000 96.2 8.8 3.3 – 24.7 100 1.7 100 1.9 

2001 88.9 8.8 2.1 – 20.7 100 0.7 100 0.6 

2002 86.5 8.2 2.5 – 17.7 100 1.1 100 1.6 

2003 69.6 7.8 3.4 – 13.4 100 1.7 100 2.2 

2004 NA NA NA NA NA NA NA 

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(g) Cohutta 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 95.6 10.7 1.2 – 44.4 

2000 128.2 12.8 3.9 – 32.7 100 1.7 100 1.4 

2001 87.3 9.8 1.8 – 29.6 100 1.0 100 1.0 

2002 95.4 10.6 2.2 – 44.4 100 1.2 100 1.3 

2003 92.9 10.4 1.2 – 34.3 100 1.2 100 1.5 

2004 98.4 10.1 1.9 – 32.4 100 1.5 100 1.3 

(h) Dolly Sods 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 86.0 9.4 0.4 – 37.2 

2000 89.3 10.4 1.3 – 26.1 100 1.1 100 1.7 

2001 82.0 8.9 2.0 – 35.7 100 0.7 100 1.5 

2002 79.1 8.7 1.3 – 37.2 100 1.0 100 0.9 

2003 91.5 9.8 0.4 – 29.8 100 1.0 100 1.3 

2004 80.8 9.9 0.9 – 31.2 100 1.5 100 1.3 

 (i) Everglades 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 63.4 6.5 1.1 – 34.4 

2000 70.5 6.2 1.1 – 24.9 100 2.3 100 2.5 

2001 63.1 6.0 1.8 – 17.5 100 1.1 100 1.3 

2002 61.8 6.3 1.4 – 23.4 100 1.0 100 1.3 

2003 67.6 7.2 1.7 – 24.1 100 1.3 100 1.3 

2004 62.0 6.6 2.1 – 34.4 100 1.5 100 1.1 

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(j) Great Smoky Mountains 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 85.7 10.1 0.5 – 35.6 

2000 92.3 10.5 2.3 – 35.6 100 1.8 100 1.7 

2001 82.2 9.8 1.8 – 29.9 100 1.0 100 1.3 

2002 78.6 9.8 1.7 – 27.9 100 1.1 100 0.7 

2003 86.7 9.9 0.5 – 32.1 100 1.1 100 1.5 

2004 86.0 10.3 1.5 – 23.9 100 1.1 100 1.2 

(k) James River Face 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 102.1 10.9 0.5 – 31.5 

2000 128.5 12.9 4.5 – 26.9 100 1.3 100 1.4 

2001 97.1 10.1 2.8 – 28.9 100 1.4 100 0.9 

2002 101.0 11.7 3.5 – 31.5 100 1.3 100 1.1 

2003 99.6 10.3 0.5 – 29.2 100 1.3 100 1.4 

2004 94 10.0 2.4 – 25.9 100 1.0 100 1.0 

(l) Linville Gorge 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 80 8.9 0.3 – 29.2 

2000 94.2 10.4 1.3 – 29.2 100 1.5 100 1.7 

2001 78.1 8.3 15 – 23.8 100 1.1 100 0.9 

2002 72.4 8.8 1.6 – 27.1 92.3 1.7 100 1.0 

2003 78.8 8.3 0.3 – 27.6 100 1.5 100 1.1 

2004 77.0 8.6 1.5 – 21.6 100 1.0 100 0.9 

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(m) Mammoth Cave 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 110.0 11.7 2.0 – 44.6 

2000 116.5 12.7 4.0 – 44.6 100 1.6 100 2.1 

2001 105.7 11.3 2.0 – 28.4 100 1.7 100 1.3 

2002 104.1 11.5 3.8 – 34.0 100 0.8 100 1.4 

2003 106.2 11.5 3.9 – 32.4 100 1.1 100 1.1 

2004 109.5 11.5 2.5 – 27.6 100 1.5 100 2.0 

(n) Mingo 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 94.7 11.5 2.4 – 50.0 

2000 101.5 12.9 2.6 – 34.5 100 1.8 100 1.2 

2001 90.4 11.3 2.4 – 50.0 100 1.1 100 1.2 

2002 80.9 9.1 3.1 – 15.4 100 1.2 100 2.4 

2003 NA NA NA NA NA NA NA 

2004 NA NA NA NA NA NA NA 

(o) Okefenokee 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 86.7 9.1 2.2 – 42.9 

2000 94.3 9.5 3.5 – 24.8 100 1.5 100 1.9 

2001 85.3 9.5 3.0 – 24.9 100 1.3 100 1.1 

2002 88.9 9.5 2.9 – 30.1 100 1.0 100 0.7 

2003 81.5 8.5 2.2 – 20.4 100 1.0 80 1.2 

2004 85.4 9.0 2.8 – 42.9 100 1.2 100 0.9 

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(p) Shenandoah 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 95.2 9.3 0.1 – 33.9 

 

2000 96.9 9.3 0.7 – 22.7 100 1.6 100 0.9 

2001 99.4 9.5 1.7 – 33.9 100 1.1 100 1.0 

2002 99.0 9.6 0.8 – 29.8 100 2.2 100 1.8 

2003 95.0 9.3 0.1 – 29.3 100 1.2 100 1.3 

2004 89.9 8.7 0.5 – 26.1 100 1.6 100 0.4 

(q) Shining Rock 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 75.1 7.8 0.2 – 57.6 

2000 85.4 8.3 1.6 – 57.6 100 1.3 100 0.9 

2001 74.5 7.8 1.1 – 24.1 100 1.1 100 0.9 

2002 65.0 8.1 0.4 – 23.2 100 1.3 100 1.2 

2003 84.2 8.4 0.2 – 34.8 100 1.6 100 1.4 

2004 65.3 7.0 0.9 – 17.8 100 1.1 100 0.9 

(r) Sipsey 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 100.8 11.1 1.6 – 36.3 

2000 104.9 11.6 3.9 – 36.3 100 2.0 100 3.1 

2001 100.8 10.7 1.6 – 23.0 100 1.1 100 1.5 

2002 95.9 10.8 4.4 – 29.0 100 1.2 100 1.2 

2003 104.1 11.7 4.0 – 28.6 100 1.0 100 1.0 

2004 95.6 10.8 31 – 26.0 100 1.2 100 1.7 

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(s) St. Marks 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 77.9 8.5 1.5 – 31.9 

 

 

2000 88.5 9.0 3.4 – 20.1 100 1.5 100 1.9 

2001 78.9 8.2 2.0 – 18.4 100 0.9 100 1.0 

2002 79.2 8.1 2.3 – 21.4 100 1.0 100 1.7 

2003 81.1 8.3 1.5 – 23.8 91.7 1.0 100 1.9 

2004 73.9 9.4 2.8 – 31.9 100 1.4 100 1.3 

(t) Swanquarter 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 81.8 7.9 0.6 – 27.0 

 

 

2000 89.7 8.3 2.2 – 17.6 100 0.6 100 2.4 

2001 79.0 7.7 1.8 – 24.9 100 1.3 100 1.9 

2002 79.3 8.1 1.8 – 22.2 100 1.3 100 1.9 

2003 78.8 7.1 0.6 – 27.0 100 1.1 100 0.9 

2004 NA NA NA NA NA NA NA 

(u) Upper Buffalo 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 73.4 8.6 0.1 – 30.0 

2000 81.0 9.3 1.1 – 30.0 100 1.1 100 1.4 

2001 64.8 7.9 0.7 – 20.7 100 0.8 100 1.4 

2002 79.2 9.2 1.7 – 27.1 100 1.0 100 1.6 

2003 77.8 9.1 0.1 – 25.1 100 1.7 100 1.5 

2004 67.0 8.6 0.7 – 23.5 100 1.3 100 1.3 

The weighted average is the average of the daily values that are weighted according to the 

frequency of occurrence of similar conditions for the full period. The weights are based on the 

CART results, and frequency of occurrence of conditions is based on the number of days in 

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each CART bin. Days that have conditions that occur more frequently are given greater weights, 

while those that occur less frequently are given lesser weights. In this manner, the frequency of 

occurrence of meteorological conditions is normalized for each year and the average extinction 

coefficient and PM2.5 values are more likely to reflect other factors such as emissions. Unusually 

high or low concentrations/extinction for a certain type of conditions (severity) will also affect the 

average. For many of the sites, the highest extinction and PM2.5 values occur in 2000. 

Otherwise the values are fairly similar for all years. The range in PM2.5, which is not normalized 

for meteorology, is also similar for each of the five years. 

For all sites, the key bins for both visibility and PM2.5 are represented for all of the years, 

although there are a few exceptions. This is expected since we are considering full year periods, 

each of which represents one fifth of the multi-year period that is used to determine the key 

bins. As we will see later in this report, this metric is more informative when we consider shorter, 

episodic periods. 

The distribution error ranges quantifies how well the frequency distribution of days among the 

bins matches that for the full baseline period. It has the units of percent since it is the average 

difference of two percentage values. For all sites, this value ranges from approximately 0.5 to 3 

percent. A smaller error indicates a better match. Considering this metric, 2002 does not stand 

out as being significantly more or less representative than the other years that comprise the 

baseline period. No one year stands out as being most typical of the period for a majority of the 

sites. The distribution error over all key visibility bins is lowest for 2002 for Brigantine, Cadiz, 

Caney Creek, Everglades, Mammoth Cave, and Okefenokee. The results vary by site. 

For example, for Cape Romain (Table 4-1e), the weighted extinction and PM2.5 values for 2002 are 

lower than on average for the full baseline period. The range in PM2.5 is typical of the other baseline 

years. The distribution error for visibility is slightly larger than for the other years in the period, and 

that for PM2.5 is about the same as the other years (except for 2000, which is quite a bit higher). 

For the GSM site (Table 4-1j), the weighted average extinction coefficient for 2002 is lower than 

on average for the full baseline period, but the average PM2.5 value is typical of the period. The 

range in PM2.5 is also typical of the other baseline years. The distribution error for visibility is 

about the same as the other years (except for 2000, which is quite a bit higher), that for PM2.5 is 

the lowest among the five years. 

For Mammoth Cave (Table 4-1m), the weighted extinction and PM2.5 values for 2002 are 

representative of the full baseline period, but slightly below the average values for the full period. 

The year 2000 has some high values, which tend to increase the five-period average. The range 

in PM2.5 is typical of the other baseline years, with the exception of 2000. The distribution error for 

visibility is the lowest among all of the years, while that for PM is in the middle. 

Considering the entire VISTAS region, it is not expected that any single year will be typical or 

representative for all areas of the Class I areas of interest. The year 2000 seems to be the least 

representative year, and 2002 is as good as or better than most of the others for most sites. 

Knowing how well the 2002 simulation period represents each area may aid the analysis and 

interpretation of the VISTAS air quality modeling results. 

4.2.2. STN Sites 

Table 4-2 summarizes and compares 2000-2004, and each individual year within this period for 

the STN sites. The summary metrics included in this table are the weighted average PM2.5

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concentration, range in PM2.5 concentration, percentage of key PM2.5 bins represented 

(considering all classes), and the relative distribution of days among the key PM2.5 bins for all 

categories (distribution error). 

Table 4-2. Summary of PM2.5 and Meteorological Characteristics for the 2000-2004 Analysis 

Period: STN Sites. 

(a) Birmingham 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 18.8 0.4 - 71.3 

2000 20.1 0.4 - 71.3 100 2.7 

2001 18.4 1.0 - 51.5 100 0.8 

2002 17.8 4.2 - 47.8 100 1.1 

2003 18.0 2.9 - 46.4 90 1.4 

2004 18.4 3.6 – 53.3 80 1.6 

(b) Charlotte 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.7 2.3 – 45.2 

2000 15.4 2.9 – 43.5 100 1.8 

2001 14.5 3.8 – 40.3 100 0.9 

2002 14.4 3.2 – 45.2 100 1.6 

2003 14.2 2.3 – 40.4 90 1.4 

2004 14.6 2.6 – 39.8 100 1.3 

(c) Chattanooga 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 15.6 2.5 – 48.6 

2000 16.0 4.8 – 48.6 100 2.3 

2001 15.8 2.5 – 47.5 100 1.6 

2002 14.5 4.2 – 31.3 100 1.1 

2003 15.4 3.0 – 41.4 90 1.6 

2004 14.8 3.1 – 31.3 100 1.1 

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 (d) Greenville-Spartanburg 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.8 0.5 – 51.5 

2000 15.5 3.5 – 51.5 100 1.7 

2001 14.8 2.4 – 40.7 92.3 0.8 

2002 14.9 1.5 – 49.8 100 1.2 

2003 14.6 0.5 – 40.1 100 0.9 

2004 14.5 3.1 – 38.0 100 0.7 

 (e) Hickory 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 15.8 2.6 – 40.7 

2000 16.7 4.7 – 38.0 100 1.1 

2001 15.6 3.8 – 40.0 100 0.9 

2002 15.5 4.5 – 40.7 100 0.9 

2003 16.1 2.6 – 39.8 100 1.2 

2004 15.7 3.2 – 37.4 100 1.0 

 (f) Huntington-Ashland 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.7 0.6 – 54.5 

2000 15.7 0.6 – 37.2 100 1.8 

2001 14.1 3.1 – 54.5 100 1.3 

2002 14.9 3.0 – 46.8 100 1.0 

2003 15.5 5.2 – 37.7 100 1.1 

2004 13.2 3.2 – 30.7 100 0.8 

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 (g) Jackson 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 13.7 1.8 – 45.3 

2000 14.0 3.2 – 41.4 100 1.1 

2001 13.3 1.8 – 40.3 100 1.5 

2002 13.0 1.8 – 45.3 100 2.0 

2003 13.5 4.5 – 31.5 100 0.7 

2004 13.6 2.3 – 33.6 100 2.0 

 (h) Kingsport-Bristol 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.8 1.9 – 49.2 

2000 15.8 4.3 – 43.0 100 1.8 

2001 14.6 3.2 – 45.7 100 1.4 

2002 14.0 2.6 – 37.5 100 0.8 

2003 14.3 1.9 – 49.2 100 1.5 

2004 14.2 3.8 – 37.7 100 1.5 

 (i) Louisville 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 17.1 3.3 – 100.6 

2000 17.4 3.5 – 54.7 100 1.5 

2001 17.3 3.5 – 53.2 100 0.9 

2002 17.7 4.1 – 100.6 100 1.0 

2003 16.4 3.5 – 55.7 91.7 0.9 

2004 15.9 3.3 – 45.8 75 1.2 

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 (j) Macon 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 16.1 1.6 – 56.2 

2000 16.8 3.8 – 56.2 100 2.1 

2001 15.9 1.6 – 39.7 100 1.4 

2002 15.2 4.3 – 41.0 100 1.2 

2003 15.2 3.5 – 36.3 100 1.6 

2004 16.2 4.0 – 43.8 100 1.7 

 (k) Memphis 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.2 1.1 – 50.0 

2000 15.2 1.1 – 50.0 100 1.6 

2001 13.8 2.7 – 41.3 100 0.9 

2002 13.8 3.6 – 49.4 91.7 0.8 

2003 14.0 3.2 – 38.0 100 0.7 

2004 13.8 3.1 – 38.2 91.7 1.6 

 (l) Montgomery 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.7 0.4 – 52.1 

2000 16.1 0.4 – 52.1 100 2.4 

2001 13.7 0.6 – 38.8 100 1.4 

2002 14.9 3.5 – 39.4 100 0.7 

2003 14.2 5.1 – 42.8 90 1.3 

2004 14.4 5.3 – 45.0 100 1.8 

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 (m) Nashville 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.9 0.2 – 42.3 

2000 15.6 0.5 – 42.3 100 2.0 

2001 14.8 0.2 – 38.2 90.9 0.8 

2002 14.6 2.6 – 39.8 100 1.1 

2003 14.9 4.2 – 42.3 100 0.7 

2004 13.8 2.2 – 36.6 100 1.4 

 (n) Raleigh 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.1 2.3 – 52.8 

2000 15.0 3.0 – 52.8 100 1.4 

2001 13.9 3.7 – 48.7 91.7 1.0 

2002 13.3 2.3 – 43.8 91.7 1.6 

2003 14.2 2.8 – 45.3 100 0.9 

2004 13.5 2.8 – 41.7 100 1.1 

 (o) Richmond 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.2 0.0 – 50.5 

2000 14.9 2.2 – 38.9 100 1.0 

2001 14.3 2.0 – 49.1 100 0.5 

2002 13.0 1.2 – 50.5 100 1.0 

2003 14.0 2.8 – 43.5 100 1.1 

2004 13.5 0.0 – 38.2 92.3 0.7 

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 (p) Savannah 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.0 3.2 – 55.3 

2000 14.7 4.7 – 44.5 100 2.3 

2001 14.9 3.2 – 55.3 100 1.4 

2002 12.8 3.9 – 30.1 100 1.5 

2003 13.5 4.1 – 49.6 88.9 0.6 

2004 13.4 4.7 – 40.2 100 2.1 

The weighted average PM2.5 values tend to be highest for 2000. Otherwise the values are fairly 

similar for all years, with some variations. The range in PM2.5, which is not normalized for 

meteorology, is also similar for each of the five years. Figure 4-6 shows the year by year 

tendencies in weighted average PM2.5 and daily maximum 24-hour average PM2.5, for each of 

the STN sites. For most sites, there is no apparent trend, especially for the meteorologically 

adjusted (weighted average) values. This indicates that PM2.5 concentrations in the urban areas 

have neither increased nor decreased during the five-year period. 

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Figure 4-6. Year-by-Year Tendencies in Weighted Average PM2.5 and Daily Maximum 24-hour 

Average PM2.5 

(a) Birmingham 

Weighted Average PM2.5: Birmingham

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Birmingham

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(b) Charlotte 

Weighted Average PM2.5: Charlotte

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Charlotte

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(c) Chattanooga 

Weighted Average PM2.5: Chattanooga

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Chattanooga

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(d) Greenville-Spartanburg 

Weighted Average PM2.5: Greenville-Spartanburg

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Greenville-Spartanburg

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(e) Hickory 

Weighted Average PM2.5: Hickory

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Hickory

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(f) Huntington-Ashland 

Weighted Average PM2.5: Huntington-Ashland

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Huntington-Ashland

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(g) Jackson 

Weighted Average PM2.5: Jackson

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Jackson

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(h) Kingsport 

Weighted Average PM2.5: Kingsport-Bristol

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Kingsport-Bristol

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(i) Louisville 

Weighted Average PM2.5: Louisville

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Louisville

0

20

40

60

80

100

120

2000 2001 2002 2003 2004

ugm-3

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(j) Macon 

Weighted Average PM2.5: Macon

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Macon

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(k) Memphis 

Weighted Average PM2.5: Memphis

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Memphis

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(l) Montgomery 

Weighted Average PM2.5: Montgomery

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Montgomery

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(m) Nashville 

Weighted Average PM2.5: Nashville

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Nashville

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(n) Raleigh 

Weighted Average PM2.5: Raleigh

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Raleigh

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(o) Richmond 

Weighted Average PM2.5: Richmond

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Richmond

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(p) Savannah 

Weighted Average PM2.5: Savannah

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Savannah

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

With few exceptions, the key bins for PM2.5 are represented for all of the years. Again, this is 

expected since we are considering full year periods, each of which represents one fifth of the 

multi-year period that is used to determine the key bins. 

The distribution error ranges from approximately 0.5 to 2.5 and quantifies how well the 

frequency distribution of days among the bins matches that for the full baseline period. No one 

year stands out as being most typical of the period for a majority of the sites. The distribution 

error over all key bins is lowest for 2002 for Chattanooga, Hickory, Kingsport-Bristol, Macon, 

and Montgomery, and close to the lowest for several other sites. Overall, 2000 is the year with 

the least representative distribution. As for the IMPROVE sites, the results vary by site. 

For example, for Charlotte (Table 4-2b), the weighted PM2.5 value for 2002 is close to the average 

for the full baseline period. The maximum concentration occurred during this year, but the range in 

PM2.5 is typical of the other baseline years. The distribution error is slightly larger than for the other 

years in the period, except for 2000. The year 2001 appears to be the most typical year. 

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For Chattanooga (Table 4-2c), the weighted average PM2.5 value for 2002 is lower than the 

average for the full baseline period and the lower values are also reflected in the range. 

Nevertheless, the frequency of conditions was normal and the distribution error is the lowest 

overall (along with that for 2004). 

For Louisville (Table 4-2i), the weighted average PM2.5 value for 2002 is slightly higher than the 

average for the full baseline period and the range indicates that there was at least one very high 

daily value (greater than 100 μgm-3) recorded during 2002. The distribution error is among the 

lowest, indicating a typical frequency of meteorological scenarios. 

For Macon (Table 4-2j), the weighted average PM2.5 value for 2002 is lower than the average for 

the full baseline period and the range is similar to that for the other years with the exception of 

2002. The distribution error is the lowest, over all the years considered. 

For the urban areas, the year 2000 seems to be the least representative year, and 2002 is as good 

as or better than most of the others for most sites. Consequently, 2002 is a representative year for 

most sites, but the specific implications of using 2002 as the model baseline year vary by site. 

4.2.3. SEARCH Sites 

Table 4-3 summarizes and compares 2000–2004, and each individual year within this period for 

the SEARCH sites. The summary metrics included in this table are the weighted average PM2.5

concentration, range in PM2.5 concentration, percentage of key PM2.5 bins represented 

(considering all classes), and the relative distribution of days among the key PM2.5 bins for all 

categories (distribution error). 

Table 4-3. Summary of PM2.5 and Meteorological Characteristics for the 2000-2004 Analysis 

Period: SEARCH Sites. 

(a) Atlanta (Jefferson St.) 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 16.6 1.1 – 66.1 

2000 16.9 3.7 – 62.6 100 1.8 

2001 16.4 2.2 – 66.1 100 0.9 

2002 16.3 3.7 – 40.2 91.7 0.8 

2003 16.2 1.5 – 47.0 100 1.0 

2004 16.8 1.1 – 49.5 100 1.7 

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 (b) Yorkville 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 13.6 0.7 – 65.2 

2000 14.5 2.3 – 65.2 100 1.5 

2001 13.2 2.5 – 54.4 100 0.7 

2002 13.2 2.6 – 34.8 100 0.6 

2003 12.0 2.2 – 43.0 91.7 1.0 

2004 13.4 0.7 – 39.5 91.7 0.4 

(c) Birmingham 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 17.9 2.8 – 75.2 

2000 18.3 3.8 – 66.4 100 2.3 

2001 17.2 3.3 – 48.9 100 1.1 

2002 17.5 3.9 – 45.3 100 0.9 

2003 16.8 2.8 – 45.0 90.9 1.4 

2004 18.0 3.2 – 75.2 100 1.4 

(d) Centreville 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 12.9 1.2 – 54.4 

2000 13.3 3.0 – 54.4 100 2.1 

2001 12.4 1.2 – 34.9 100 0.9 

2002 13.1 2.9 – 48.6 91.7 1.4 

2003 12.3 1.8 – 39.5 91.7 0.6 

2004 12.8 2.6 – 40.8 91.7 0.8 

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 (e) Pensacola 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 12.8 1.2 – 52.5 

2000 12.6 3.4 – 45.5 100 2.0 

2001 13.1 2.6 – 52.5 100 0.9 

2002 13.2 3.3 – 40.7 100 1.4 

2003 12.5 1.6 – 41.7 90.9 1.1 

2004 12.4 1.2 – 40.7 100 0.9 

(f) Outlying Landing Field 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 11.8 0.7 – 130.9 

2000 12.4 0.7 – 130.9 100 2.6 

2001 11.1 2.4 – 32.9 100 1.1 

2002 11.3 2.3 – 38.3 100 1.8 

2003 11.5 2.2 – 32.6 100 1.7 

2004 11.7 2.3 – 44.8 100 1.6 

(g) Gulfport 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 11.4 0.3 – 44.0 

2000 11.0 0.3 – 44.0 100 1.4 

2001 11.4 2.3 – 41.4 100 1.2 

2002 11.4 2.8 – 31.9 100 1.3 

2003 11.6 2.7 – 30.1 100 0.6 

2004 11.5 1.6 – 43.5 100 1.6 

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 (h) Oak Grove 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 11.8 1.5 – 90.1 

2000 11.9 2.5 – 41.4 100 2.2 

2001 11.8 2.3 – 90.1 100 0.7 

2002 11.4 2.2 – 67.1 100 1.3 

2003 11.5 1.5 – 43.9 100 0.8 

2004 11.6 2.2 – 37.2 100 0.6 

For the inland sites the weighted average PM2.5 values tend to be highest for 2000, lower for 

2001-2003, and then high again for 2004. For the coastal sites, the values are fairly similar for 

all years, with some variations. The range in PM2.5 indicates that the highest values were 

recorded early during the five-year period. Figure 4-7 shows the year by year tendencies in 

weighted average PM2.5 and daily maximum 24-hour average PM2.5 for each of the SEARCH 

sites. For most sites, there is no apparent trend in the meteorologically adjusted (weighted 

average) values. The maximum values follow the tendency described above. 

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Figure 4-7. Year-by-Year Tendencies in Weighted Average PM2.5 and Daily Maximum 24-hour 

Average PM2.5 for Each of the SEARCH Sites. 

(a) Atlanta 

Weighted Average PM2.5: Atlanta

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Atlanta

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(b) Yorkville 

Weighted Average PM2.5: Yorkville

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Yorkville

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(c) Birmingham 

Weighted Average PM2.5: Birmingham

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Birmingham

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(d) Centreville 

Weighted Average PM2.5: Centreville

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Centreville

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(e) Pensacola 

Weighted Average PM2.5: Pensacola

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Pensacola

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(f) OLF 

Weighted Average PM2.5: OLF

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: OLF

0

20

40

60

80

100

120

140

2000 2001 2002 2003 2004

ugm-3

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(g) Gulfport 

Weighted Average PM2.5: Gulfport

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Gulfport

0

20

40

60

80

2000 2001 2002 2003 2004

ugm-3

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(h) Oak Grove 

Weighted Average PM2.5: Oak Grove

0

5

10

15

20

25

2000 2001 2002 2003 2004

ugm-3

Daily Maximum PM2.5: Oak Grove

0

20

40

60

80

100

120

2000 2001 2002 2003 2004

ugm-3

With few exceptions, the key bins for PM2.5 are represented for all of the years. The distribution 

error ranges from approximately 0.5 to 2.5 and quantifies how well the frequency distribution of 

days among the bins matches that for the full baseline period. The distribution error over all key 

bins is lowest for 2002 for Atlanta, Yorkville, and Birmingham. Overall, 2000 is the year with the 

least representative distribution. 

For Atlanta (Table 4-3a), the weighted PM2.5 value for 2002 is close to the average for the full 

baseline period. The range reflects a lower maximum value than for the other years and not all key 

bins are represented. Nevertheless, the distribution error is the lowest among all years considered. 

For Birmingham (Table 4-3c), the weighted average PM2.5 value for 2002 is also close to the 

average for the full baseline period, and the range is typical for the middle years. The 

distribution error is the lowest overall. 

For the SEARCH sites, 2002 does not include some of the higher values of the other years but 

other indicators suggest that this is a representative year for the SEARCH sites. 

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4.3. Selection Subset Episodes for Model-Based Sensitivity Analysis 

The CART results were also used in selecting subset periods of 2002 for PM2.5 modeling and 

sensitivity analysis. The episode selection methods are presented in this section and the key 

question of “How well do subset modeling periods chosen by VISTAS for emission sensitivity 

analysis capture the range of relationships between meteorology and air quality for each site of 

interest and for the VISTAS region?” is examined. 

4.3.1. Episode Selection 

The goal of this exercise was to identify two approximate month-long subset periods of 2002 to 

represent the conditions and concentration levels associated with high PM2.5 events in as many 

areas as possible throughout the VISTAS region. The two periods were also to represent both 

winter and summer types of regimes. The primary focus of this exercise was PM2.5; however, 

information about ozone was also included in the final stages of the analysis. Because the 

selected episode periods were potentially to be used for PM2.5 modeling of urban areas, we 

considered only the results for the STN and SEARCH sites. The episode selection methodology 

is outlined below. 

First we prepared color-coded charts of daily PM2.5 concentrations for each STN and SEARCH 

site and identified (primarily visually) winter and summer periods with a range of high and low 

concentrations for as many sites as possible. We also used the episode selection tool to identify 

periods that sample a range of key conditions for selected groups of areas. 

We then input these dates into the CART-based meteorological characterization tool and used 

the summaries provided by the tool to assess and compare the representativeness of the 

periods with respect to frequent (key) meteorological conditions, annual average PM2.5 (and 

ozone) concentrations, and speciation. We considered all of the VISTAS STN and SEARCH 

areas, but gave more attention to those with the higher PM2.5 design values. 

The analysis components included several characterization metrics that focused on how well 

the weighted annual average and range of PM2.5 concentrations represent these same metrics 

for the full baseline period, and the degree to which the key PM2.5 bins are represented by the 

identified periods. We also compared the compositional averages for the identified days with 

those for the baseline periods. Finally, we examined the range and frequency of occurrence of 

wind directions at the surface and 850 mb levels relative to a longer period of record. 

The winter period was selected first. From three candidate winter periods, the period 19 

November–20 December 2002 was selected to best capture the PM2.5 concentrations 

(especially for the sites with the higher PM2.5 design values) and the key high PM2.5 CART bins. 

The wind directions for this period also represented the average wintertime distribution slightly 

better than the other two candidates, for several locations. 

Seven candidate summertime periods were then reviewed with respect to representing the 

summer conditions for the baseline period and complementing the selected wintertime period in 

representing the annual range of conditions of the baseline period. The summertime period 

3 June–10 July 2002 was selected. When this period is combined with the wintertime period, 

optimum representation of the key bins (for all categories) and the distribution of days among 

the key bins are achieved. The distribution of wind directions for high PM days is also 

representative of the longer period. Finally, the period includes high ozone days for the areas 

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Meteorological Representativeness and Episode Selection Exercises 

with the higher design values. This exercise demonstrates the use of the episode selection and 

meteorological characterization tool to identify episodic periods for air quality modeling. 

4.3.2. Episode Representativeness 

The characteristics, attributes, and limitations of the episode periods are examined and 

compared in this section. Although the episode selection only considered the STN and 

SEARCH sites, we examine the representativeness of the selected episodes for the IMPROVE, 

STN and SEARCH sites. 

IMPROVE Sites 

Table 4-4 summarizes and compares 2000-2004, 2002, and the combined episode periods for 

the IMPROVE sites. The summary metrics are the same as those for Table 4-1. The weighted 

extinction coefficients and average concentrations provide information on how well 2002 

represents average conditions for the baseline period (as discussed earlier in this section) and 

then how well the subset episodes represent the 2002 annual period, when the days are 

weighted to best represent the expected frequency of occurrence of the different types of 

conditions. For many of the sites, good to very good agreement is achieved between the 2002 

and episode values. The range in PM2.5 concentration for the episode days indicates that, for 

many of the sites, the episode days include the peak days for 2002 (that is, the upper end of the 

range is the same as for 2002). The episodes contain 71 days, and as expected, do not always 

include days from all of the key bins. However, considering all sites, between 70 and 100 

percent of the key bins are captured for both visibility and PM by the episode days – this varies 

by site. As expected, the distribution errors are larger for the episode periods, indicating that the 

episodes do not necessarily sample the various types of days with the frequency that is typical 

of the longer periods. For several of the coastal sites, including Cape Romain, Chassahowitzka, 

Everglades, and Swanquarter, the distribution error for the episode periods is not that much 

greater than that for 2002. Further inland, where more variable meteorology may lead to larger 

differences between the conditions described by the CART bins, the difference in the errors 

tends to be greater. 

Table 4-4. Summary of Visibility, PM2.5 and Meteorological Characteristics for 2000-2004, 2002, 

and the 2002 VISTAS Episodic Analysis Periods: IMPROVE Sites. 

(a) Breton 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 78.5 7.6 1.2 – 21.5 100 

2002 71.2 6.7 1.8 – 16.4 100 1.6 100 0.7 

Episodes 69.1 6.1 3.8 – 8.5 81.8 3.3 77.8 3.4 

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(b) Brigantine 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 95.6 9.7 1.4 – 39.2 

2002 93.6 9.6 1.4 – 36.5 100 0.9 100 1.7 

Episodes 101.1 9.5 3.6 – 36.5 81.3 2.3 100 5.4 

(c) Cadiz 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 107.4 11.0 0.6 – 31.3 

2002 107.4 11.1 4.1 – 30.2 100 1.1 100 1.0 

Episodes 107.5 10.3 4.1 – 30.2 85.7 4.3 100 4.1 

(d) Caney Creek 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 83.0 9.0 0.3 – 28.3 

2002 92.1 8.9 0.5 – 28.3 100 0.9 100 1.0 

Episodes 93.4 7.9 0.5 – 26.2 86.7 1.6 90 2.8 

(e) Cape Romain 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 82.0 8.6 1.1 – 30.1 

2002 79.8 8.0 1.1 – 22.6 100 1.3 100 1.1 

Episodes 79.1 7.3 1.4 – 16.4 85.7 2.4 90.9 2.2 

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(f) Chassahowitzka 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 89.5 8.7 2.1 – 24.7 

2002 86.5 8.2 2.5 – 17.7 100 1.1 100 1.6 

Episodes 87.3 7.7 3.1 – 12.6 91.7 2.7 100 1.8 

(g) Cohutta 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 95.6 10.7 1.2 – 44.4 

2002 95.4 10.6 2.2 – 44.4 100 1.2 100 1.3 

Episodes 90.8 10.6 3.9 – 44.4 100 2.4 87.5 2.6 

(h) Dolly Sods 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 86.0 9.4 0.4 – 37.2 

2002 79.1 8.7 1.3 – 37.2 100 1.0 100 0.9 

Episodes 81.6 8.2 2.1 – 37.2 100 3.3 100 4.9 

(i) Everglades 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 63.4 6.5 1.1 – 34.4 

2002 61.8 6.3 1.4 – 23.4 100 1.0 100 1.3 

Episodes 69.1 6.6 1.4 – 23.4 81.8 2.5 88.9 1.9 

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Meteorological Representativeness and Episode Selection Exercises 

(j) Great Smoky Mountains 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 85.7 10.1 0.5 – 35.6 

2002 78.6 9.8 1.7 – 27.9 100 1.1 100 0.7 

Episodes 72.1 9.2 2.0 – 25.4 71.4 2.3 100 2.5 

(k) James River Face 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 102.1 10.9 0.5 – 31.5 

2002 101.0 11.7 3.5 – 31.5 100 1.3 100 1.1 

Episodes 92.1 11.2 4.5 – 31.5 70.0 2.4 88.9 2.5 

(l) Linville Gorge 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 80 8.9 0.3 – 29.2 

2002 72.4 8.8 1.6 – 27.1 92.3 1.7 100 1.0 

Episodes 55.8 8.3 3.1 – 21.6 76.9 4.2 88.9 2.3 

(m) Mammoth Cave 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 110.0 11.7 2.0 – 44.6 

2002 104.1 11.5 3.8 – 34.0 100 0.8 100 1.4 

Episodes 100.8 10.9 6.1 – 25.3 91.7 3.2 88.9 4.4 

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Meteorological Representativeness and Episode Selection Exercises 

(n) Mingo 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 94.7 11.5 2.4 – 50.0 

2002 80.9 9.1 3.1 – 15.4 100 1.2 100 2.4 

Episodes NA NA NA NA NA NA NA 

(o) Okefenokee 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 86.7 9.1 2.2 – 42.9 

2002 88.9 9.5 2.9 – 30.1 100 1.0 100 0.7 

Episodes 80.2 8.3 2.9 – 28.3 100 2.3 90 2.6 

(p) Shenandoah 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 95.2 9.3 0.1 – 33.9 

2002 99.0 9.6 0.8 – 29.8 100 2.2 100 1.8 

Episodes 88.0 8.3 2.7 – 26.1 100 3.9 88.9 3.5 

(q) Shining Rock 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 75.1 7.8 0.2 – 57.6 

2002 65.0 8.1 0.4 – 23.2 100 1.3 100 1.2 

Episodes 47.8 10.8 2.8 – 21.0 81.8 3.6 77.8 1.9 

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Meteorological Representativeness and Episode Selection Exercises 

(r) Sipsey 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 100.8 11.1 1.6 – 36.3 

2002 95.9 10.8 4.4 – 29.0 100 1.2 100 1.2 

Episodes 87.6 10.5 5.5 – 20.8 91.7 2.5 100 4.1 

(s) St. Marks 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 77.9 8.5 1.5 – 31.9 

2002 79.2 8.1 2.3 – 21.4 100 1.0 100 1.7 

Episodes 64.5 6.8 2.4 – 15.7 91.7 3.2 77.8 3.8 

(t) Swanquarter 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–

2004 81.8 7.9 0.6 – 27.0 

 

 

2002 79.3 8.1 1.8 – 22.2 100 1.3 100 1.9 

Episodes 65.8 7.0 2.2 – 22.2 83.3 2.3 75 2.4 

(u) Upper Buffalo 

Period 

Weighted 

Average 

Extinction 

Coefficient 

(Mm-1) 

Weighted 

Average 

PM2.5 

Concentration 

(μgm-3) 

Range in 

PM2.5

Concentration 

(μgm-3) 

Percentage 

of Key 

Visibility 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

Visibility 

Bins (%) 

Percentage 

of Key 

PM2.5 Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 73.4 8.6 0.1 – 30.0 

2002 79.2 9.2 1.7 – 27.1 100 1.0 100 1.6 

Episodes 78.2 8.3 3.5 – 26.0 92.3 2.8 88.9 3.2 

Some additional plots are provided to characterize the overall representativeness of the urbanPM2.5-based episode periods for selected example sites, namely Cape Romain, Great Smoky 

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Meteorological Representativeness and Episode Selection Exercises 

Mountains, and Mammoth Cave. Figure 4-8 compares the average concentration of the PM 

species for the three time periods, 2000-2004, 2002, and 1 June – 10 July and 19 November – 

19 December, 2002 (the combined subset episode periods). Figure 4-9 examines and 

compares the distribution of surface wind direction, by wind direction quadrant, for the three sets 

of dates. 

Figure 4-8. Comparison of Species Concentrations (μgm-3) for Sulfate (SO4), Nitrate (NO3), 

Organic Carbon (OC), Elemental Carbon (EC) and Ammonium (NH4) for 2000-2004, 2002, and 2002 

VISTAS Episode Periods: IMPROVE Sites. 

(a) Cape Romain 

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

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Meteorological Representativeness and Episode Selection Exercises 

(b) Great Smoky Mountains 

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

(c) Mammoth Cave 

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

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Meteorological Representativeness and Episode Selection Exercises 

Figure 4-9. Distribution of Surface Wind Directions by Quadrant for 2000-2004, 2002, and 2002 

VISTAS Episode Periods: IMPROVE Sites. 

(a) Cape Romain 

0

10

20

30

40

50

60

NE SE SW NW

Wind Direction Quadrant

Percent of Days (%)

2000-2004

2002

Episodes

(b) Great Smoky Mountains 

0

10

20

30

40

50

60

NE SE SW NW

Wind Direction Quadrant

Percent of Days (%)

2000-2004

2002

Episodes

ICF International 4-59 VISTAS Meteorological Characterization 

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Meteorological Representativeness and Episode Selection Exercises 

(c) Mammoth Cave 

0

10

20

30

40

50

60

NE SE SW NW

Wind Direction Quadrant

Percent of Days (%)

2000-2004

2002

Episodes

For Cape Romain (Figure 4-8a), the average concentrations for all species are very similar for 

all three periods. The subset periods match the averages for 2002 very closely. The 

distributions of wind directions (Figure 4-9a) for the three periods also agree very well, with 

fewer occurrences of northeasterly winds for the episodes, than the longer periods. 

For GSM (Figure 4-8b), both 2002 and the episodes have slightly higher sulfate concentrations 

than the full baseline period, and 2002, on average, has slightly lower organic carbon. The 

distributions of wind directions (Figure 4-9b) for the three periods agree quite well. 2002 has a 

higher percentage of days with southeasterly winds and a lower percentage of days with 

southwesterly winds than the full period. The distribution for the episode periods follows that for 

2002 fairly closely. 

For Mammoth Cave (Figure 4-8c), the episode days have, on average, slightly lower sulfate and 

slightly higher nitrate and organic carbon concentrations than both 2002 and the full baseline 

period, which are very well matched in terms of average concentrations. The episodes also 

have a greater percentage of days with southeasterly winds and a lesser percentage of days 

with northwesterly winds than the longer periods (Figure 4-9c). 

STN Sites 

Table 4-5 summarizes and compares 2000-2004, 2002, and the combined episode periods for 

the STN sites. The summary metrics are the same as those for Table 4-2. The weighted 

average PM2.5 concentrations provide information on how well 2002 represents average 

conditions for the baseline period (as discussed earlier in this section) and then how well the 

subset episodes represent the 2002 annual period, when the days are weighted to best 

represent expected frequency of occurrence of the different types of conditions. 

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Meteorological Representativeness and Episode Selection Exercises 

Table 4-5. Summary of PM2.5 and Meteorological Characteristics for 2000-2004, 2002, and the 2002 

VISTAS Episodic Analysis Periods: STN Sites. 

(a) Birmingham 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 18.8 0.4 - 71.3 

2002 17.8 4.2 - 47.8 100 1.1 

Episodes 18.8 7.1 – 41.5 100 3.5 

 (b) Charlotte 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.7 2.3 – 45.2 

2002 14.4 3.2 – 45.2 100 1.6 

Episodes 14.7 3.8 – 34.5 100 3.2 

 (c) Chattanooga 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 15.6 2.5 – 48.6 

2002 14.5 4.2 – 31.3 100 1.1 

Episodes 13.5 4.3 – 31.3 90 3.9 

 (d) Greenville-Spartanburg 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.8 0.5 – 51.5 

2002 14.9 1.5 – 49.8 100 1.2 

Episodes 15.7 4.5 – 37.3 42.3 1.9 

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Meteorological Representativeness and Episode Selection Exercises 

 (e) Hickory 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 15.8 2.6 – 40.7 

2002 15.5 4.5 – 40.7 100 0.9 

Episodes 15.3 5.8 – 33.5 100 4.2 

 (f) Huntington-Ashland 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.7 0.6 – 54.5 

2002 14.9 3.0 – 46.8 100 1.0 

Episodes 13.7 3.0 – 46.8 100 3.7 

 (g) Jackson 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 13.7 1.8 – 45.3 

2002 13.0 1.8 – 45.3 100 2.0 

Episodes 11.9 4.8 – 24.8 77.8 2.9 

(h) Kingsport-Bristol 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.8 1.9 – 49.2 

2002 14.0 2.6 – 37.5 100 0.8 

Episodes 13.8 4.9 – 34.4 90.9 3.4 

ICF International 4-62 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 286
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Meteorological Representativeness and Episode Selection Exercises 

 (i) Louisville 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 17.1 3.3 – 100.6 

2002 17.7 4.1 – 100.6 100 1.0 

Episodes 18.2 7.1 – 100.6 91.7 3.9 

 (j) Macon 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 16.1 

2002 15.2 4.3 – 41.0 100 1.2 

Episodes 13.6 5.2 – 29.3 88.9 3.0 

 (k) Memphis 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.2 1.1 – 50.0 

2002 13.8 3.6 – 49.4 91.7 0.8 

Episodes 14.5 3.9 – 36.4 75 3.0 

 (l) Montgomery 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.7 0.4 – 52.1 

2002 14.9 3.5 – 39.4 100 0.7 

Episodes 13.9 6.5 – 28.9 90 2.4 

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Meteorological Representativeness and Episode Selection Exercises 

 (m) Nashville 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.9 0.2 – 42.3 

2002 14.6 2.6 – 39.8 100 1.1 

Episodes 15.1 6.6 – 39.8 81.8 3.1 

 (n) Raleigh 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.1 2.3 – 52.8 

2002 13.3 2.3 – 43.8 91.7 1.6 

Episodes 13.5 4.3 – 43.8 91.7 2.2 

 (o) Richmond 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.2 0.0 – 50.5 

2002 13.0 1.2 – 50.5 100 1.0 

Episodes 13.9 2.8 – 50.5 92.3 3.7 

(p) Savannah 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 14.0 3.2 – 55.3 

2002 12.8 3.9 – 30.1 100 1.5 

Episodes 11.9 5.7 – 20.3 88.9 2.0 

Overall good to very good agreement is achieved between the 2002 and episode values, and 

the weighted average concentration for the episode days is within approximately 1 μgm-3 of the 

2002 average value for many of the sites. For several sites, the episode days include the peak 

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days for 2002 (the upper end of the range is the same as for 2002). Considering all sites, 

between 42 and 100 percent of the key bins are captured by the episode days. The distribution 

errors are larger for the episode periods, as the episodes do not necessarily sample the various 

types of days with the frequency that is typical of the longer periods. 

Figure 4-10 compares the average concentration of the PM species for 2000-2004, 2002, and 

the combined episode periods for four example sites: Charlotte, Chattanooga, Louisville, and 

Macon. Figure 4-11 examines and compares the distribution of surface wind direction, by wind 

direction quadrant, for the three sets of dates, for these same sites. 

Figure 4-10. Comparison of Species Concentrations (μgm-3) for Sulfate (SO4), Nitrate (NO3), 

Organic Carbon (OC), Elemental Carbon (EC) and Ammonium (NH4) for 2000-2004, 2002, and 2002 

VISTAS Episode Periods: STN Sites. 

(a) Charlotte 

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

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(b) Chattanooga 

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

(c) Louisville 

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

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(d) Macon 

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

Figure 4-11. Distribution of Surface Wind Directions by Quadrant for 2000-2004, 2002, and 2002 

VISTAS Episode Periods: STN Sites. 

(a) Charlotte 

0

10

20

30

40

50

60

NE SE SW NW

Wind Direction Quadrant

Percent of Days (%)

2000-2004

2002

Episodes

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(b) Chattanooga 

0

10

20

30

40

50

60

NE SE SW NW

Wind Direction Quadrant

Percent of Days (%)

2000-2004

2002

Episodes

(c) Louisville 

0

10

20

30

40

50

60

NE SE SW NW

Wind Direction Quadrant

Percent of Days (%)

2000-2004

2002

Episodes

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(d) Macon 

0

10

20

30

40

50

60

NE SE SW NW

Wind Direction Quadrant

Percent of Days (%)

2000-2004

2002

Episodes

 Average concentrations for sulfate and organic carbon are higher for 2002, compared to the 

baseline period, and even higher for the episode periods for Charlotte (Figure 4-10a). There 

area also differences in the distribution of wind directions among the three periods (Figure 4-

11a). Both 2002 and the episode periods show a lesser proportion of southwesterly winds than 

the baseline period. The 2002 annual period makes up for this with winds from the northeast, 

and the episodes make up for this with winds from the southeast. 

For Chattanooga (Figure 4-10b), the episode periods have higher average species 

concentrations for sulfate, organic carbon, and, to some extent, nitrate and ammonium, than the 

longer periods. They are also characterized by a greater proportion of southeasterly and a less 

proportion of southwesterly winds than the longer periods (Figure 4-11b). 

Similarly, for Louisville (Figure 4-10c), the episode periods have higher average species 

concentrations for all species than the longer periods. In this case, a lower fraction of the days 

have northwesterly winds (Figure 4-11c). 

For Macon (Figure 4-10d), 2002 is characterized by higher average sulfate than the baseline 

period and the episode days have higher organic carbon concentrations than both 2002 and the 

full baseline period. The episode days have a greater percentage of days with northwesterly 

winds compared to the longer periods (Figure 4-11d). Differences in the wind direction 

distributions between 2002 and the full baseline period are relatively small. 

SEARCH Sites 

Table 4-6 summarizes and compares 2000-2004, 2002, and the combined episode periods for 

the STN sites. The summary metrics are the same as those for Table 4-2. 

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Table 4-6. Summary of PM2.5 and Meteorological Characteristics for 2000-2004, 2002, and the 2002 

VISTAS Episodic Analysis Periods: SEARCH Sites. 

(a) Atlanta (Jefferson St.) 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 16.6 1.1 – 66.1 

2002 16.3 3.7 – 40.2 91.7 0.8 

Episodes 17.2 5.0 – 40.2 91.7 3.0 

 (b) Yorkville 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 13.6 0.7 – 65.2 

2002 13.2 2.6 – 34.8 100 0.6 

Episodes 13.6 3.8 – 34.8 91.7 1.9 

 (c) Birmingham 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 17.9 2.8 – 75.2 

2002 17.5 3.9 – 45.3 100 0.9 

Episodes 18.5 5.5 – 41.2 90.9 3.0 

 (d) Centreville 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 12.9 1.2 – 54.4 

2002 13.1 2.9 – 48.6 91.7 1.4 

Episodes 11.8 4.1 – 39.7 75 2.7 

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 (e) Pensacola 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 12.8 1.2 – 52.5 

2002 13.2 3.3 – 40.7 100 1.4 

Episodes 12.1 3.4 – 31.5 90.9 4.2 

 (f) Outlying Landing Field 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 11.8 0.7 – 130.9 

2002 11.3 2.3 – 38.3 100 1.8 

Episodes 10.4 3.6 – 21.0 77.8 3.7 

 (g) Gulfport 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 11.4 0.3 – 44.0 

2002 11.4 2.8 – 31.9 100 1.3 

Episodes 10.0 3.3 – 18.9 72.7 2.9 

 (h) Oak Grove 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 11.8 1.5 – 90.1 

2002 11.4 2.2 – 67.1 100 1.3 

Episodes 10.1 3.0 – 27.5 63.6 2.3 

The weighted average PM2.5 concentrations are quite similar for all three sets of dates, and the 

weighted average concentration for the episode days is within approximately 1 μgm-3 of the 

2002 average value for all of the sites. The range in PM2.5 concentration is similar for 2002 and 

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the episode days for the inland sites, but not for the coastal sites. Considering all sites, between 

64 and 100 percent of the key bins are captured by the episode days. The distribution errors are 

larger for the episode periods, as the episodes do not necessarily sample the various types of 

days with the frequency that is typical of the longer periods. 

Figure 4-12 compares the average concentration of the PM species for 2000-2004, 2002, and 

the combined episode periods for two of the SEARCH sites: Atlanta and Birmingham. Figure 4-

13 examines and compares the distribution of surface wind direction, by wind direction 

quadrant, for the three sets of dates, for these same sites. 

Figure 4-12. Comparison of Species Concentrations (μgm-3) for Sulfate (SO4), Nitrate (NO3), 

Organic Carbon (OC), Elemental Carbon (EC) and Ammonium (NH4) for 2000-2004, 2002, and 2002 

VISTAS Episode Periods: SEARCH Sites. 

(a) Atlanta 

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

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(b) Birmingham 

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

Figure 4-13. Distribution of Surface Wind Directions by Quadrant for 2000-2004, 2002, and 2002 

VISTAS Episode Periods: SEARCH Sites. 

(a) Atlanta 

0

10

20

30

40

50

60

NE SE SW NW

Wind Direction Quadrant

Percent of Days (%)

2000-2004

2002

Episodes

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(b) Birmingham 

0

10

20

30

40

50

60

NE SE SW NW

Wind Direction Quadrant

Percent of Days (%)

2000-2004

2002

Episodes

For Atlanta (Figure 4-12a), the average concentrations for all species are very similar for 2002 

and the full baseline period. The episode days are characterized by higher sulfate and organics 

than 2002. The plot of the distribution of wind directions (Figure 4-13a) shows that all three 

periods are similar with regard to the predominantly northwesterly winds, the distribution among 

the other three quadrants differs. 

For Birmingham (Figure 4-12b), episodes have higher sulfate concentrations than both 2002 

and the full baseline period. Organic carbon is lower than the baseline for 2002 and higher than 

the baseline for the episodes. The distribution of wind directions (Figure 4-13b) for 2002 and the 

full baseline period are fairly similar. The episode days have a higher percentage of days with 

northeasterly winds and a lower percentage of days with southwesterly winds than the longer 

periods. 

4.4. Calculation of Meteorologically-Based Weighting Factors 

The CART results and tool were also used in the calculation of weighting factors related to 

regional haze and PM2.5 for the modeled days. The weighting factors are intended to be applied 

to the VISTAS atmospheric modeling results so that they can better represent the baseline 

period for the projection of future air quality related values. Weights were calculated for each 

site based on 1) similarities between the modeled days and the regulatory Best and Worst days 

(for regional haze) and 2) the frequency of occurrence of the conditions associated with the 

modeled days during the 2000-2004 baseline period (for regional haze and PM2.5). Additional 

detail on the calculation of the weighting factors is provided below. 

The weighting factors for the modeled days can be used to weight each day’s contribution to the 

average relative reduction factor that is used to estimate future year air quality. There are a 

number of different ways in which the weighting factors can be used. For illustrative purposes, 

we provide a simple example. Consider the quarterly relative reduction factor (RRF) for a 

species, which is defined as the ratio of the quarterly average future-year to base-year 

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simulated species concentration. Assume that the quarterly average value is based on two 

modeled days. 

The unweighted RRF is equal to (C1f + C2f)/(C1b + C2b) where C1 and C2 are the simulated 

concentrations for days 1 and 2, and the subscripts f and b refer to the future and base 

scenarios. 

If the days are assigned weighting factors of w1 and w2, the weighted RRF becomes (w1 ⋅ C1f + 

w2 ⋅ C2f)/(w1 ⋅ C1b + w2 ⋅ C2b). 

The weighting factors are available in Excel format. 

4.4.1. Annual Weighting Factors for Regional Haze 

Two approaches were used to calculate the weighting factors for regional haze. Both relied on 

the identification of the 20 percent “Best” and “Worst” visibility days for the period 2000-2004, 

using the IMPROVE methodology in which extinction coefficient is calculated as discussed in 

Section 2 of this report but using a monthly average f(rh) rather than a daily f(rh), as applied in 

this study. Only days with data were considered eligible for weighting. Days with data that are 

similar to one or more of the IMPROVE-method Best or Worst days (also referred to as the 

regulatory Best and Worst days) were assigned weighting factors. A day was considered to be 

similar to a Best or Worst day if it was assigned to the same CART bin as a Best or Worst day. 

Weighting factors were calculated separately for Best days and Worst days, and the set of days 

representing Best days is mutually exclusive from the set of days representing Worst days. 

In the first approach, a weighting factor was assigned to each similar day based on both the 

overall frequency of occurrence of meteorological conditions (the total number of days in the 

CART bin) as well as the number of regulatory Best or Worst days in each bin. 

In the second approach, the weighting factors were based only on the number of Best or Worst 

days in each bin. 

Meteorological Frequency and Best/Worst Based Weighting Factors 

We calculated weighting factors for each of the 21 IMPROVE sites for all 2002 dates for which 

there were valid visibility data for the site in question. Weighting factors for use in the Best days 

and Worst days assessments were calculated separately. 

In calculating the weighting factors, we relied on the CART analysis results and used the bins 

and the number of days within each bin to define the meteorological and air quality conditions 

and their frequency of occurrence. Weights were assigned to each bin based on the total 

number of days in the bin and the number of Best (or Worst) days in the bin from a list of the 

20% Best (B) (or 20% Worst (W)) days provided by VISTAS. The process consists of seven 

steps, as follows: 

1) Each CART bin containing one or more B (or W) days is identified and the number of B (or 

W) days in the bin is counted (#B (or #W)). 

2) Each CART bin is assigned a weight equal to the total number of days in the bin divided by 

the total number of days included in the CART analysis (T/TT). 

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3) Each CART bin containing one or more B (or W) day is assigned a second weighting factor 

equal to #B (or #W) divided by the total number of B (or W) days included in the analysis 

(B/TB (or W/TW)). 

4) Each bin containing one or more of the selected days is identified and a bin weight (binwt) is 

calculated as the product of the two weighting factors above, T/TT and B/TB (or W/TW), 

divided by the sum of each term over all bins represented by one or more selected days. 

5) Binwt is then normalized to account for unrepresented bins, giving an adjusted bin weight 

(adjbinwt). For all bins containing at least one B (or W) day and at least one selected day, 

adjbinwt sums to 1. 

6) Adjbinwt is divided by the number of selected days within each bin to give the final weighting 

factor for that bin (Day Wt). 

7) Day Wt is assigned to the relevant dates based on each date’s bin classification. 

Days were only assigned weights if the extinction coefficients were within the ranges 

appropriate to the Best or Worst classification categories. For the Best days, these are 

Categories 1 and 2 (Category 1 represents the 20 percent best days using daily extinction and 

f(rh) values; Category 2 was also considered). For the Worst days, these are Categories 3, 4, 

and 5 (Categories 4 and 5 combined represent the 20 percent worst days using daily extinction 

and f(rh) values and Category 3 is the neighboring category). For bins containing both B and W 

days, certain days were assigned factors to represent Best days and other days were assigned 

factors to represent Worst days. 

The weighting factors accommodate the use of more than just the Best and Worst days in the 

future projection of regional haze by including similar days to the Best and Worst days in the 

calculations. The weighting factors for the Best and Worst days only provide an improved 

representation of the frequency of occurrence of the conditions associated with the Best and 

Worst days, considering the full baseline period. 

Best/Worst Only Based Weighting Factors 

This is a simplified version of the approach described in the previous section. It considers only 

the number of Best or Worst days in a bin. Again, we calculated weighting factors for each of 

the 21 IMPROVE sites for all 2002 dates for which there were valid visibility data for the site in 

question. Weighting factors for use in the Best days and Worst days assessments were 

calculated separately 

In calculating the weighting factors, we relied on the CART analysis results to identify days with 

similar conditions to the regulatory Best and Worst days. Weights were assigned to each bin 

based on the number of B (or W) days in the bin from a list of the 20% Best (B) (or 20% Worst 

(W)) days provided by VISTAS. The process consists of five steps, as follows: 

1) Each CART bin containing one or more B (or W) days is identified and the number of B (or 

W) days in the bin is counted (#B (or #W)). 

2) Each CART bin containing one or more B (or W) day and one or more of the selected days 

is assigned a weight (binwt) equal to #B (or #W) divided by the total number of B (or W) 

days included in the analysis (B/TB (or W/TW)). 

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3) Binwt is then normalized to account for unrepresented bins, giving an adjusted bin weight 

(adjbinwt). For all bins containing at least one B (or W) day and at least one selected day, 

adjbinwt sums to 1. 

4) Adjbinwt is divided by the number of selected days within each bin to give the final weighting 

factor for that bin (Day Wt). 

5) Day Wt is assigned to the relevant dates based on each date’s bin classification. 

As for the first approach, days were only assigned weights if the extinction coefficients were 

within the ranges appropriate to the Best or Worst classification categories. 

The weighting factors accommodate the use of more than just the Best and Worst days in the 

future projection of regional haze by including similar days to the Best and Worst days in the 

calculations. These weighting factors take into account the number of Best and Worst days in a 

bin, however, they do not account for the overall frequency of occurrence of the conditions 

associated with the Best and Worst days, considering the full baseline period. 

4.4.2. Episodic Weighting Factors for PM2.5 

For PM2.5, weighting factors were calculated for each day of the two subset episode periods 1 

June – 10 July and 19 November – 19 December, 2002, and for each STN and SEARCH site. 

These factors were based on the frequency of occurrence of the air quality/meteorological 

conditions represented by the episode day (based on the total number of days in the CART bin 

to which the day is assigned). All episode days with data were considered eligible for weighting. 

In calculating the weighting factors, we relied on the CART analysis results and used the bins 

and the number of days within each bin to define the meteorological and air quality conditions 

and their frequency of occurrence. Weights were assigned to each bin based on the total 

number of days in the bin. The process consists of four steps, as follows: 

1) Each CART bin containing one or more of the episode days is assigned a weight (binwt) 

equal to the total number of days in the bin divided by the total number of days included in 

the CART analysis (T/TT). 

2) Binwt is normalized to account for unrepresented bins, giving an adjusted bin weight 

(adjbinwt). For all bins containing at least one episode day, adjbinwt sums to 1. 

3) Adjbinwt for each bin is divided by the number of episode days within the bin to give the final 

weighting factor for that bin (Day Wt). 

4) Day Wt is assigned to the episode dates based on each date’s bin classification. 

The weighting factors are expected to provide an improved representation of the frequency of 

occurrence of the conditions associated with the full baseline period. 

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5. Key Findings and Implications for VISTAS Air Quality 

Modeling 

The CART results provide insight into the relationships between meteorology, PM2.5, and visibility 

that are important to atmospheric modeling. Some key findings are summarized in this section. 

CART Application 

The application of CART included several sensitivity tests involving variations to the input dataset. 

Comparison of the results from the application of CART with and without PM2.5 input data 

demonstrates that including PM2.5 is important to classification accuracy. This result indicates that 

regional buildup and transport of fine particles and related precursor species influences regional 

visibility and PM2.5 concentrations. Overall, better classification accuracy for PM2.5, compared to 

extinction coefficient, especially for the IMPROVE sites, indicates that the relationships between 

the input parameters and the characteristic parameter are better defined for PM2.5 at these sites. 

This is possibly due the more complex role of moisture in determining light extinction – affecting 

both particle formation and the contribution of sulfate and nitrate particle species to light extinction. 

For both visibility and PM2.5, moisture is an important input to CART, and some information about 

moisture is needed in order to achieve good classification. We found daily average relative 

humidity to be the most effective form of the moisture parameter. 

Parameter Importance 

The CART results indicate that temperature, wind speed, and relative humidity are key 

meteorological parameters that distinguish days with different fine particle mass and visibility 

values in the southeastern U.S. Considering visibility for the IMPROVE sites, the most important 

parameters include: relative humidity, prior day PM2.5 concentrations at potential upwind 

monitoring sites, 850 mb temperature, surface temperature (reflecting seasonal differences), 

and wind speed (both near the surface and aloft). For PM2.5 relative humidity is less important, 

but the list of important parameters is similar. One key difference when comparing parameter 

importance for the inland, coastal, and mountain sites is that relative humidity and persistence 

(which, for coastal sites, represents a sea or gulf breeze) are more important for the coastal 

sites, compared to the inland and mountain sites. The temperature parameters are most 

important for the mountain sites. Wind directions are not used frequently enough in the CART 

trees to be considered important parameters to the overall classification, but they are often used 

near the end of the CART pathways to distinguish poor visibility and high PM2.5 days. 

For PM2.5 for the STN and SEARCH sites, the most important parameters include: prior day 

PM2.5 concentrations, 850 mb temperature, surface temperature, and wind speed (both near the 

surface and aloft). Relative humidity is also important for the coastal SEARCH sites. 

These results vary by site, although, there are similarities among the sites within similar 

geographical features. An assessment of the meteorological inputs for air quality modeling 

should emphasize good representation of these key parameters. 

Site Groupings 

The CART-derived parameter importance results were used to examine potential site groupings. 

We identified similarities in the important parameters for the analysis sites and attributed these 

to similarities in the mechanisms influencing air quality at these sites. In general, the CARTderived groupings, which are based on parameter importance, are also supported by similarities 

in location and geography. The groupings for the IMPROVE sites are different for visibility 

versus PM2.5. These groupings may provide the basis for assessing model performance and 

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understanding the reasons for model performance problems. The grouping may also aid the 

interpretation of differences in the effectiveness of air quality measures across the monitoring 

sites and regions. 

CART Classification Results 

CART also provides insight into the types of conditions that, based on their frequency of 

occurrence over a multi-year period, should be represented in an assessment of air quality 

responses to emissions changes. Poor visibility and high PM2.5 days are grouped into bins that 

are characterized by different meteorological and prior-day air quality conditions. While there 

are similarities in the conditions that describe the key (most populated) bins, there are also 

some important differences that relate directly to source-receptor relationships and potentially 

control strategy effectiveness. 

One of the more notable differences among the key poor visibility and high PM2.5 bins is wind 

direction, especially surface wind direction. Wind direction, however, does not have a high 

parameter importance ranking. For many of the cases we examined, this is primarily because 

wind direction was used in the outermost (lowest) branches of the CART tree, such that days 

with similar features in many respects were separated into different bins (characterized by 

different extinction or PM2.5 values) according to wind direction. Thus, wind direction can be 

important, but only in differentiating a small number of days. For several sites, large differences 

in average temperature among the key bins indicate that the regimes vary with season. Other 

differences include prior day PM2.5 concentration, relative humidity, stability, and degree of 

persistence (indicating a sea or gulf breeze) for the coastal sites. The differences in the 

individual parameters combine to represent the different regimes, and there are multiple 

regimes associated with poor visibility and high PM2.5 for all of the areas of interest. The 

differences among the key bins emphasize the need to include days that represent the different 

types of meteorological conditions that accompany poor visibility and high PM events in any 

model-based air quality planning exercise. 

The CART analyses also provide insight into PM2.5 composition for different (key) types of poor 

visibility days and high PM2.5 days. In general, analysis of the compositional characteristics for 

the key bins for the 20 percent haziest days for the IMPROVE sites within the VISTAS region 

indicates that, on average, ammonium sulfate and organic carbon are the two most important 

contributors to poor visibility and that their relative contributions vary by site, by bin, and with 

meteorology. For the inland IMPROVE sites, ammonium sulfate is the dominant contributor. For 

the coastal IMPROVE sites the contributions from ammonium sulfate and organic carbon on the 

poor visibility days are more comparable than at the interior sites. As for visibility, the high PM2.5

concentration bins are distinguished from the lower concentration bins by higher sulfate and 

organic matter concentrations. 

The STN compositional charts show a much larger proportional contribution from organic matter 

compared to those for the IMPROVE sites, especially for the higher PM2.5 bins. This is in part 

due to differences between the IMPROVE and STN measurement techniques for organic 

carbon. With the higher values for organics, the dominant species varies by bin, much more so 

than for the IMPROVE sites. These variations are attributable to differences in meteorology as 

well as regional pollutant transport. 

The compositional charts for the PM2.5 for the SEARCH sites also show a much larger 

proportional contribution from organics than the IMPROVE charts, especially for the higher 

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Key Findings and Implications for VISTAS Air Quality Modeling 

PM2.5 bins. The relative ranking of the species contributions is similar to that for the STN sites. A 

comparison of the compositional averages for Birmingham using the STN and SEARCH data, 

shows that the organic matter and overall PM2.5 values are higher in the STN data, but that the 

tendency for organic matter to be the dominant species appears in both sets of results for the 

more urban sites. 

Simulation Period Representativeness 

The 2002 annual simulation period includes days that capture the general meteorological 

characteristics associated with a range of visibility at the IMPROVE sites and represents well 

the typical frequency of occurrence of these conditions. However, somewhat lower than average 

concentrations and average extinction coefficients characterize 2002 for some sites. PM2.5

values for the STN and SEARCH sites are also lower than average compared to other years 

within the baseline period. There is no apparent trend in the meteorologically adjusted (weighted 

average) annual average values of PM2.5 for the STN and SEARCH sites. 

While it is not expected that any single year will be typical or representative for all areas of the 

Class I and urban areas of interest, the CART results enhance the understanding of how well 

the 2002 simulation period represents each area and this will allow VISTAS to use and interpret 

their air quality modeling results appropriately. 

Two subset episode periods from 2002, comprising a total of 71 days, were selected to 

represent the conditions and concentration levels associated with high PM2.5 events in as many 

areas as possible throughout the VISTAS region. These include a summer episode (1 June – 10 

July) and a winter episode (19 November – 19 December, 2002). For many of the sites, the 

summer period includes the peak days for 2002. As expected, the episode periods, do not 

include days from all of the key bins for all sites. Considering all sites, between approximately 

40 and 100 percent of the key bins are included by the episode days – this varies by site. The 

distribution errors are larger for the episode periods, compared to the annual periods, indicating 

that the episodes do not sample the different regimes with the frequency that is typical of the 

longer periods. 

Weighting Factors 

The CART results and tool were also used in the calculation of weighting factors for both 

regional haze and PM2.5 for the annual and episodic modeled days. The weighting factors were 

intended to improve the ability of the modeling results for 2002 and the subset periods to 

represent the full baseline period. The weighting factors for regional haze were calculated based 

on similarities between the modeled days and the regulatory 20% Best and 20% Worst days 

and the frequency of occurrence of the conditions associated with the modeled days during the 

2000-2004 baseline period. The weighting factors for PM2.5 were based on the frequency of 

occurrence of the meteorological conditions. 

The weighting factors are intended to be applied to the VISTAS atmospheric modeling results 

so that they can better represent the baseline period for the projection of future air quality 

related values. In this manner, application of CART has improved the understanding of the 

conditions contributing to elevated PM2.5 and poor visibility in the southeastern states and has 

provided the basis for the enhanced analysis and interpretation of atmospheric modeling results. 

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Key Findings and Implications for VISTAS Air Quality Modeling 

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6. References 

ARA. 2005. SEARCH website available by Atmospheric Research Associates at 

http://www.atmospheric-research.com/studies/SEARCH/

Brieman, L., J. H. Friedman, R. A. Olshen, and C. J. Stone. 1984. Classification and Regression 

Trees. Wadsworth, Belmont, California. 

CIRA. 2005. VIEWS website available at, http://vista.cira.colostate.edu/views/

Cox, W. M. and S. Chu, 1996. Assessment of interannual ozone variation in urban areas from a 

climatological perspective. Atmos. Environ., 30(14), 2615-2625. 

Deuel, H. P., and S. G. Douglas. 1998. “Episode Selection for the Integrated Analysis of Ozone, 

Visibility, and Acid Deposition for the Southern Appalachian Mountains.” ICF/Systems 

Applications International, Inc., San Rafael, California (SYSAPP-98/07r1). 

Douglas, S. G., J. B. Mangahas, A. B. Hudischewskyj, G. L. Glass, and W. S. Hartley, 2003. 

“Examination of Inter-Variable Relationships and Implications for Modeling Episode 

Selection Using the 1999/2000 SEARCH Database”, ICF/Systems Applications 

International, Inc., San Rafael, California (03-060). 

Douglas, S. G., J. B. Mangahas, A. B. Hudischewskyj, and J. L. Haney, 2004. “The 

Development of PM2.5 Forecasting Tools for Selected Cities in the MARAMA Region,”

ICF/Systems Applications International, 101 Lucas Valley Rd., Suite 260, San Rafael 

California 94903, (04-046). 

Eder, B. K., J. M. Davis, P. Bloomfield, 1993. A characterization of the spatiotemporal variability 

of non-urban ozone concentrations over the eastern United States. Atmos. Environ., 

27A, 2645-2668. 

EPA. 2001. Guidance for Demonstrating Attainment of Air Quality Goals for PM2.5 and Regional 

Haze. Draft. 

EPA, 2004. Procedures for Estimating Future PM2.5 Values for the CAIR Final Rule by 

Application of the (Revised) Speciated Modeled Attainment Test. Available at 

http://www.epa.gov. 

EPA. 2005. Aerometric Information Retrieval System database available at http://www.epa.gov. 

NCDC. 2005. National Climatic Data Center website available at 

http://www.ncdc.noaa.gov/oa/ncdc.html. 

Regional Haze Regulations; Final Rule. 1999: Federal Register, 64, 35713-35774. 

Steinberg, Dan, and Phillip Colla. CART—Classification and /regression Trees. San Diego, CA: 

Salford Systems, 1997. 

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References 

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Appendix: Comparison of Results for the STN and SEARCH 

Birmingham Sites 

Two CART analyses were conducted for Birmingham. Both analyses used PM2.5 data for the 

North Birmingham monitoring site. For the first analysis, the PM2.5 data were based on STN 

measurements and the surface meteorological inputs were based on data from the nearby NWS 

monitoring site. For the second analysis, the SEARCH data were used to prescribe both the 

PM2.5 and surface meteorological inputs. In both cases, upper-air meteorological data from the 

nearby NWS measurement site were used. PM2.5 data are available for both sites for the entire 

2000-2004 period. The analysis using the SEARCH data includes one additional year of 

speciated data (for the year 2000). In this appendix, we compare the results and inferences for 

the two Birmingham analyses for PM2.5. 

Comparative Analysis 

CART classification accuracy for PM2.5 is very similar for the two analyses—78.5 percent for the 

STN analysis and 77.1 percent for the SEARCH analysis. The relative importance of the input 

parameters in constructing the CART classification tree is also very similar for the two analyses, 

as displayed in Figures A-1 and A-2. Prior-day PM concentrations, surface wind speed, prior-day 

700 mb wind speed, relative humidity, and stability are, in order, the five most important 

parameters for the STN analysis. These same five parameters along with 850 mb wind speed are 

most important for the SEARCH analysis. The order of importance is roughly the same, with 850 

mb wind speed surpassing relative humidity in relative importance for the SEARCH analysis. 

Figure A-1. Parameter Importance for the CART PM2.5 Analysis: Birmingham STN Site. 

0 20 40 60 80 100

Clouds 

Avg 850 mb w ind direction 

Avg 850 mb w ind speed 

Yesterday's 700 mb w ind direction (PM)

Yesterday's 700 mb w ind speed (PM)

700 mb height difference 

Stability 

Avg 850 mb temp 

Rain

Max surface pressure

Persistence

Surface w ind direction

Surface w ind speed

Relative humidity at noon

Avg surface temp

Regional avg of yesterday's max PM

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Figure A-2. Parameter Importance for the CART PM2.5 Analysis: Birmingham SEARCH Site. 

0 20 40 60 80 100

Clouds 

Avg 850 mb w ind direction 

Avg 850 mb w ind speed 

Yesterday's 700 mb w ind direction (PM)

Yesterday's 700 mb w ind speed (PM)

700 mb height difference 

Stability

Avg 850 mb temp 

Rain

Max surface pressure

Persistence

Surface w ind direction

Surface w ind speed

Relative humidity 

Avg surface temp

Regional avg of yesterday's max PM

A more detailed look at the CART classification trees confirms that analysis results are similar, 

with respect to the conditions leading to high PM2.5 and, in CART terms, the high PM2.5

classification bins. However, the CART tree developed using the SEARCH data has more bins 

than that developed using the STN data (32 versus 26). 

The CART input data for the two analyses are summarized in Tables A-1 and A-2. These tables 

present the average value of each input parameter for each PM2.5 classification category for the 

Birmingham STN and SEARCH datasets. The four PM2.5 categories are defined by the 70, 90, 

and 97 percentile values of PM2.5 mass, which are slightly different for the two sites. For the 

STN site, the ranges for Categories 1 through 4 are <22.5, 22.5-32.5, 32.5-40 and ≥ 40 μgm-3. 

For the SEARCH site, the ranges are <20, 20-30, 30-37.5 and ≥ 37.5 μgm-3. 

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Appendix: Comparison of Results for the STN and SEARCH Birmingham Sites 

Table A-1. Summary of Average Input Parameters for Each CART Classification Category: PM2.5

CART Analysis for the Birmingham STN Site. 

The ranges in PM2.5 for Categories 1 through 4 are as follows: <22.5, 22.5-32.5, 32.5-40 and ≥ 40 μgm-3. 

Category 1 Category 2 Category 3 Category 4 

PM2.5 Parameters 

Yesterday's FM at Birmingham (μg/m3) 16.8 25.2 29.9 40.5 

Yesterday's FM at Atlanta (μg/m3) 16.9 22.1 24.8 31.1 

Yesterday's FM at Memphis (μg/m3) 12.9 17.7 19.8 25.1 

Yesterday's FM at Nashville (μg/m3) 13.3 18.5 20.9 24.7 

Surface Meteorological Parameters 

Max. surface temperature (°C) 20.9 25.9 27.2 29.0 

Min. surface temperature (°C) 10.9 14.0 14.4 15.2 

Relative humidity (%) 70.4 66.5 63.4 62.3 

Surface wind speed (ms-1) 2.5 1.5 1.2 0.9 

Surface wind direction (degrees) 279 79 87 11 

Persistence 0.8 0.8 0.7 0.7 

Sea level pressure (mb) 1021 1021 1021 1022 

Rainfall (inches) 0.2 0.1 0.0 0.0 

Rain (# periods) 1.0 0.6 0.3 0.1 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 10.2 12.9 13.6 14.3 

Temperature PM 850 mb (°C) 10.2 13.8 14.3 15.2 

Stability at Birmingham (°C) -0.1 2.1 2.9 4.1 

Geopotential height difference 700 mb at Birmingham (m) -1.2 5.3 0.6 2.8 

Wind speed yesterday 700 mb at Birmingham (ms-1) 12.7 8.1 7.9 6.0 

Wind direction yesterday 700 mb at Birmingham (degrees) 265 302 322 339 

Wind speed yesterday 850 mb at Birmingham (ms-1) 8.9 5.6 5.0 3.9 

Wind speed AM 850 mb at Birmingham (ms-1) 10.2 6.3 5.8 4.3 

Wind speed PM 850 mb at Birmingham (ms-1) 8.9 5.9 5.5 3.7 

Wind direction yesterday 850 mb at Birmingham (degrees) 255 345 10 32 

Wind direction AM 850 mb at Birmingham (degrees) 264 261 258 284 

Wind direction PM 850 mb at Birmingham (degrees) 271 238 90 315 

Recirculation at Birmingham 0.0 0.1 0.1 0.3 

Cloud average 1.8 1.6 1.6 1.6 

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Appendix: Comparison of Results for the STN and SEARCH Birmingham Sites 

Table A-2. Summary of Average Input Parameters for Each CART Classification Category: PM2.5

CART Analysis for the Birmingham SEARCH Site. 

 The ranges in PM2.5 for Categories 1 through 4 are as follows: <20, 20-30, 30-37.5 and ≥ 37.5 μgm-3. 

Category 1 Category 2 Category 3 Category 4 

PM2.5 Parameters 

Yesterday's FM at Birmingham (μg/m3) 16.5 24.1 29.5 38.2 

Yesterday's FM at Atlanta (μg/m3) 16.7 21.6 23.7 30.8 

Yesterday's FM at Memphis (μg/m3) 12.7 17.0 19.9 23.3 

Yesterday's FM at Nashville (μg/m3) 13.2 17.5 20.6 23.4 

Surface Meteorological Parameters 

Max. surface temperature (°C) 21.6 26.0 27.5 28.4 

Min. surface temperature (°C) 11.5 14.3 13.9 14.7 

Relative humidity (%) 70.9 66.4 63.0 62.3 

Surface wind speed (ms-1) 1.8 1.3 1.0 0.8 

Surface wind direction (degrees) 247 73 18 345 

Persistence 0.8 0.8 0.7 0.7 

Station pressure (mb) 998 998 998 1000 

Rainfall (inches) 0.2 0.1 0.0 0.0 

Rain (# periods) 1.0 0.6 0.4 0.3 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 10.2 12.5 13.0 13.9 

Temperature PM 850 mb (°C) 10.3 13.2 13.9 14.7 

Stability at Birmingham (°C) -0.3 2.1 3.1 3.5 

Geopotential height difference 700 mb at Birmingham (m) -1.7 5.2 2.3 5.1 

Wind speed yesterday 700 mb at Birmingham (ms-1) 12.8 8.7 7.7 6.9 

Wind direction yesterday 700 mb at Birmingham (degrees) 265 298 307 329 

Wind speed yesterday 850 mb at Birmingham (ms-1) 9.1 5.9 4.6 4.5 

Wind speed AM 850 mb at Birmingham (ms-1) 10.3 6.6 5.6 5.0 

Wind speed PM 850 mb at Birmingham (ms-1) 8.9 6.3 5.5 4.3 

Wind direction yesterday 850 mb at Birmingham (degrees) 252 345 349 14 

Wind direction AM 850 mb at Birmingham (degrees) 264 251 283 243 

Wind direction PM 850 mb at Birmingham (degrees) 273 219 321 270 

Recirculation at Birmingham 0.02 0.08 0.13 0.28 

Cloud average 1.8 1.6 1.6 1.5 

The values and variations in the PM2.5 related parameters among the classification categories 

are very similar for the two datasets. 

The surface meteorological parameters are also very similar, with some exceptions for the surface 

wind directions. For the STN analysis, the Category 3 surface wind directions are easterly, on 

average. For the SEARCH analysis, they are north-northeasterly. For the STN analysis, the 

Category 4 surface wind directions are north-northeasterly, on average. For the SEARCH analysis, 

they are north-northwesterly. In both cases, the surface winds have a northerly component on the 

highest PM2.5 days. The westerly component is more pronounced in the SEARCH data summary. 

The average values and tendencies for the upper-air parameters are also very similar, with the 

exception of the 850 mb wind directions for the two highest categories. Again the SEARCH data 

summary shows a more pronounce westerly component at higher concentrations, especially at the 

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Appendix: Comparison of Results for the STN and SEARCH Birmingham Sites 

time of the evening sounding. The greater differences for wind direction compared to other parameters 

may be due, in part, to the uncertainties inherent in calculating an average wind direction (if the wind 

directions included in the averaging vary considerably, the average may not be very meaningful). 

From both analyses, we can summarize that high PM2.5 for Birmingham is associated with high 

temperatures, high PM2.5 on the previous day (local & potentially upwind sites), very low wind 

speeds near the surface and low wind speeds aloft, westerly wind components aloft and 

northerly wind components near the surface, and stable lapse rates. 

Table A-3 compares the characteristics of key high PM2.5 bins (Category 4) for the Birmingham 

STN and SEARCH analyses. Key bins are those containing the greatest number of correctly 

classified days. For ease of comparison, we focused on the key Category 4 bins (which contain 

subsets of the days with the highest concentrations). There are two key bins for the STN 

analysis, and three key bins for the SEARCH analysis. Due to different units between the two 

analyses, the row containing surface pressure was omitted from the combined table. 

Table A-3. Summary of Average Input Parameters for Key Bins for CART Classification Category 

4: PM2.5 CART Analysis for Birmingham. 

The ranges in PM2.5 for Category 4 are ≥ 37.5 and ≥ 40 μgm-3 for the STN and SEARCH analyses, respectively. 

STN SEARCH 

Bin 19 Bin 10 Bin 25 Bin 20 Bin 24 

PM2.5 Parameters 

Yesterday's FM at Birmingham (μg/m3) 50.7 32.4 51.1 33.1 35.8 

Yesterday's FM at Atlanta (μg/m3) 37.6 25.6 39.3 23.5 25.5 

Yesterday's FM at Memphis (μg/m3) 28.3 22.2 27.8 18.2 20.8 

Yesterday's FM at Nashville (μg/m3) 27.7 19.5 28.9 18.7 17.9 

Surface Meteorological Parameters 

Max. surface temperature (°C) 28.3 29.6 28.7 23.7 30.4 

Min. surface temperature (°C) 14.5 14.6 14.0 10.2 15.9 

Relative humidity (%) 63.1 61.6 58.6 64.8 58.4 

Surface wind speed (ms-1) 0.7 0.3 0.5 0.5 0.7 

Surface wind direction (degrees) 342 112 344 27 180 

Persistence 0.8 0.5 0.7 0.6 0.7 

Rainfall (inches) 0.0 0.0 0.0 0.0 0.0 

Rain (# periods) 0.1 0.2 0.0 0.2 0.1 

Upper-Air Meteorological Parameters 

Temperature AM 850 mb (°C) 13.6 14.6 13.5 11.3 15.0 

Temperature PM 850 mb (°C) 14.4 15.9 14.1 12.3 15.9 

Stability at Birmingham (°C) 4.5 4.0 4.6 2.9 4.3 

Geopotential height difference 700 mb at Birmingham (m) 1.3 5.9 0.8 -14.7 30.1 

Wind speed yesterday 700 mb at Birmingham (ms-1) 5.8 6.0 4.7 9.0 6.8 

Wind direction yesterday 700 mb at Birmingham (degrees) 34 22 354 63 338 

Wind speed yesterday 850 mb at Birmingham (ms-1) 3.6 4.5 2.9 7.0 2.8 

Wind speed AM 850 mb at Birmingham (ms-1) 3.7 4.0 3.7 6.1 4.2 

Wind speed PM 850 mb at Birmingham (ms-1) 2.9 3.2 2.9 4.9 3.7 

Wind direction yesterday 850 mb at Birmingham (degrees) 34 22 37 27 90 

Wind direction AM 850 mb at Birmingham (degrees) 270 45 270 180 270 

Wind direction PM 850 mb at Birmingham (degrees) 270 180 360 207 243 

Recirculation at Birmingham 0.4 0.2 0.5 0.0 0.4 

Cloud average 1.5 1.5 1.4 1.6 1.6 

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Appendix: Comparison of Results for the STN and SEARCH Birmingham Sites 

For the STN analysis, the PM2.5 concentration for Category 4 is greater than or equal to 40 μgm3

. Bin 19 is distinguished by a much higher prior-day value PM2.5 concentration than Bin 10. The 

temperature and humidity characteristics of the two bins are similar. Both key bins are 

characterized by very low surface wind speeds, but different surface wind directions. Surface 

winds are southeasterly for Bin 10 and northwesterly for Bin 19. Upper-level wind speeds are 

lower (slightly) for Bin 19. Upper-level wind directions are northeasterly to southerly for Bin 10, 

and primarily westerly (on the current day) for Bin 19. 

For the SEARCH analysis, the PM2.5 concentration for Category 4 is greater than or equal to 

37.5 μgm-3. Bin 25 is distinguished by a much higher prior-day value PM2.5 concentration, and in 

this regard is similar to Bin 19 from the STN analysis. Bin 20 is distinguished by lower 

temperatures and slightly higher relative humidity than the other two SEARCH Category 4 bins. 

All three key bins are characterized by very low surface wind speeds, but surface wind 

directions differ among the three bins. Surface winds are northeasterly for Bin 20, southerly for 

Bin 24, and northwesterly for Bin 25. Upper-level wind speeds are lowest (in general) for Bin 25 

and highest for Bin 20. Upper-level winds (current day) are southerly to southwesterly for Bin 

20, westerly to southwesterly for Bin 24 and westerly to northerly for Bin 25. 

If we compare the STN and SEARCH results, we find that Bin 19 from the STN analysis is 

similar in many respects to Bin 25 from the SEARCH analysis. Key similarities (that also 

distinguish these bins from other Category 4 bins within their respective analyses) include very 

high PM2.5 concentration on the prior day, northwesterly surface winds, low wind speeds aloft, 

and a transition from northeasterly to westerly winds aloft from the prior day to the morning of 

the current day. Bin 10 from the STN analysis has some features in common with Bin 20 of the 

SEARCH analysis and some features in common with Bin 24 of the SEARCH analysis. For 

example, Bins 10 (STN) and 24 (SEARCH) both have, on average, southerly wind components 

aloft during the afternoon hours of the current day. In some cases, the combined characteristics 

of SEARCH Bins 20 and 24 seem to represent Bin 10 (STN). For example, the surface wind 

directions for SEARCH Bins 20 and 24 (northeasterly and southerly) when combined give a 

resultant wind direction similar to that for STN Bin 10 (southeasterly). It is interesting that for all 

of the Category 4 bins for both analyses, the prior-day 850 mb winds are from the northeast. 

In summary, both CART analyses separate the days with very high prior-day concentrations and 

northwesterly to northerly winds from the remaining Category 4 days. The analysis using the 

SEARCH data appears to further divide the remaining days into two groups that are distinguished 

by temperature, relative humidity, surface and upper-air wind directions, and upper-air wind 

speeds. We have not explored the reasons for this additional and apparently meaningful 

segregation, but possible reasons include use of collocated surface meteorological data (for the 

SEARCH analysis) or that differences between the measurement techniques lead to the 

identification of different relationships between the PM2.5 values and the other input parameters. 

As part of our analysis, we also examined PM2.5 composition for key bins corresponding to each 

Birmingham analysis. Figures A-3 and A-4 show the average composition for all key PM2.5 bins 

for the STN and SEARCH analysis, respectively. Note that the scales are different. 

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Figure A-3. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: 

Birmingham STN Site. 

Birmingham Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

24.00

4 (417) 8 (193) 24 (97) 2 (38) 25 (27) 6 (24) 11 (45) 26 (7) 19 (23) 10 (11)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

Figure A-4. Average Elemental Carbon (EC), Nitrate (NO3), Organic Matter (OM), and Sulfate (SO4) 

Concentrations (μgm-3) for Key PM2.5 Bins for All CART Classification Categories: 

Birmingham SEARCH Site. 

Birmingham SEARCH Key PM Bins: Component Averages

0.00

4.00

8.00

12.00

16.00

20.00

5 (568) 9 (213) 27 (137) 4 (53) 31 (47) 28 (24) 10 (22) 14 (29) 25 (24) 20 (9) 24 (7)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

Avg. Conc. (μg/m3)

EC

NO3

OM

SO4

A comparison of the compositional averages for Birmingham using the STN (Figure A-3) and 

SEARCH (Figure A-4) data shows that the organic matter and overall PM2.5 values are higher in 

the STN data, but that the tendency for organic matter to be the dominant species appears in 

both sets of results. For all key Category 4 PM2.5 bins (for both the STN and SEARCH analysis), 

organic matter is the dominant species. However, the relative proportion of the species 

concentrations is different for each bin. This may be due to the differences in the average wind 

directions. As noted earlier, we found that all of the key bins are characterized by very low 

surface wind speeds, but, on average, the days within the bins have different wind directions. 

The similarities in the average parameter values noted earlier for Bins 19 (STN) and 25 

(SEARCH) are not apparent in the relative values of the average species concentrations. 

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The compositional analysis results for Birmingham (especially for the SEARCH data) show a 

higher contribution of elemental carbon than for most other sites, and this may be related to 

emissions from the steel industry facilities that are located in Birmingham. 

The CART results and meteorological characterization tool were used to explore several 

questions related to modeling episode period representativeness. The characteristics of the 

2000-2004 baseline period and each individual year comprising that period are examined for 

Birmingham using both the STN and SEARCH data in Tables A-4 and A-5. The summary 

metrics included in this table are the weighted average PM2.5 concentration, range in PM2.5

concentration, percentage of key PM2.5 bins represented (considering all classes), and the 

relative distribution of days among the key PM2.5 bins for all categories (distribution error). 

These terms are explained in more detail in the main report. 

Table A-4. Summary of PM2.5 and Meteorological Characteristics for the 2000-2004 Analysis 

Period: Birmingham STN Site. 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 18.8 0.4 – 71.3 

2000 20.1 0.4 – 71.3 100 2.7 

2001 18.4 1.0 – 51.5 100 0.8 

2002 17.8 4.2 – 47.8 100 1.1 

2003 18.0 2.9 – 46.4 90 1.4 

2004 18.4 3.6 – 53.3 80 1.6 

Table A-5. Summary of PM2.5 and Meteorological Characteristics for the 2000-2004 Analysis 

Period: Birmingham SEARCH Site. 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 17.9 2.8 – 75.2 

2000 18.3 3.8 – 66.4 100 2.3 

2001 17.2 3.3 – 48.9 100 1.1 

2002 17.5 3.9 – 45.3 100 0.9 

2003 16.8 2.8 – 45.0 90.9 1.4 

2004 18.0 3.2 – 75.2 100 1.4 

The differences in the ranges and the weighted average concentrations between the STN and 

SEARCH summaries are attributable to differences in the measured data. The distribution 

ICF International A-8 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 316
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Appendix: Comparison of Results for the STN and SEARCH Birmingham Sites 

errors, however, vary similarly among the years for the two datasets. This indicates that in both 

CART analyses, the days are similarly distributed among the key bins. The results for both 

analyses suggest that 2002 is one of the more representative years for Birmingham. 

The characteristics, attributes, and limitations of the combined VISTAS episode periods (1 June 

– 10 July and 19 November – 19 December, 2002) for PM2.5 for Birmingham are examined and 

compared in Table A-6 and A-7 for the STN and SEARCH analyses, respectively. The summary 

metrics are the same as those for Tables A-4 and A-5. 

Table A-6. Summary of PM2.5 and Meteorological Characteristics for 2000-2004, 2002, and the 2002 

VISTAS Episodic Analysis Periods: Birmingham STN Site. 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over 

All Key 

PM2.5 Bins 

(%) 

2000–2004 18.8 0.4 – 71.3 

2002 17.8 4.2 – 47.8 100 1.1 

Episodes 18.8 7.1 – 41.5 100 3.5 

Table A-7. Summary of PM2.5 and Meteorological Characteristics for 2000-2004, 2002, and the 2002 

VISTAS Episodic Analysis Periods: Birmingham SEARCH Site. 

Period 

Weighted 

Average PM2.5 

Concentration 

(μgm-3) 

Range in PM2.5

Concentration 

(μgm-3) 

Percentage of 

Key PM2.5 

Bins 

Represented 

(%) 

Distribution 

Error Over All 

Key PM2.5 

Bins (%) 

2000–2004 17.9 2.8 – 75.2 

2002 17.5 3.9 – 45.3 100 0.9 

Episodes 18.5 5.5 – 41.2 90.9 3.0 

In both cases, the weighted average concentration for the episode days is 1 μgm-3 higher than 

the 2002 average value and the episode days include at least one high PM2.5 day but not the 

peak day for 2002. The distribution errors are similar for the two analyses and the larger errors 

for the episode periods indicate that the episodes do not sample the various types of days with 

the frequency that is typical of 2002 and multi-year periods. 

Finally, to characterize the overall representativeness of the urban-PM2.5-based episode 

periods, Figure A-5 compares the average concentration of the PM species for 2000-2004, 

2002, and the combined subset episode periods. 

ICF International A-9 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 317
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Appendix: Comparison of Results for the STN and SEARCH Birmingham Sites 

Figure A-5. Comparison of Species Concentrations (μgm-3) for Sulfate (SO4), Nitrate (NO3), 

Organic Carbon (OC), Elemental Carbon (EC) and Ammonium (NH4) for 2000-2004, 2002, and 2002 

VISTAS Episode Periods: Birmingham. 

(a) STN 

μ g m-3

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

μ g m-3

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

(b) SEARCH 

μ g m-3

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

μ g m-3

0

1

2

3

4

5

6

7

8

SO4 NO3 OC EC NH4

2000-2004 2002 Episodes

ICF International A-10 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 318
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Appendix: Comparison of Results for the STN and SEARCH Birmingham Sites 

For both datasets, the average concentrations for all species for 2002 are similar to those for the full 

period. Using the STN data (Figure A-5a), the episodes have higher organic carbon and slightly 

higher sulfate, nitrate and elemental carbon concentrations than both 2002 and the full period. Using 

the SEARCH data, (Figure A-5b), the episodes have slightly higher sulfate concentrations than both 

2002 and the full baseline period. Note that we used two methods for the calculation of the average 

species concentrations for the episodes, first we used all data and then we recalculated using only 

data for those days with both STN and SEARCH data. Results for the second method are shown in 

the plots, but the conclusions are the same for both methods. The representativeness of the 

concentration characteristics of the episode days differs between the two datasets. 

Summary of Findings 

In summary, there are differences in the measured PM2.5 and species concentrations between the 

STN and SEARCH datasets for Birmingham. Despite the differences in the PM2.5 concentrations, 

the variation in the average characteristics of the days within percentage-based PM2.5 classification 

categories is similar between the two datasets. Consequently, the STN and SEARCH CART 

analyses for Birmingham are similar with respect to classification accuracy, relative importance of 

the input parameters, and the overall conditions leading to the high PM2.5 classification bins. 

Both CART analyses separate the days with very high prior-day concentrations and 

northwesterly to northerly winds from the remaining high PM2.5 days. The analysis using the 

SEARCH data provides some additional detail and further divides the remaining days into two 

groups with different physical characteristics. Use of collocated surface meteorological data in 

the SEARCH analysis may allow CART to better detect the relationships between the PM2.5

values and the meteorological parameters, or the SEARCH PM2.5 measurement techniques may 

be better in tune with the effects of meteorology. 

The concentration characteristics of the key bins for the STN and SEARCH analysis are consistent 

in that organic matter tends to be the dominant species in both sets of results. The relative species 

concentrations, however, vary among the key bins and between the two analyses. 

For both analyses, the 2002 and subset episode days are similarly distributed among the key bins 

and the results for both analyses suggest that 2002 is one of the more meteorologically 

representative years for Birmingham, considering the period 2000-2004. The representativeness 

of the concentration characteristics of the episode days differs between the two datasets. 

ICF International A-11 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 319
Characterization of Meteorology and Its Relationships to Fine Particulate Mass and Visibility in the VISTAS Region

Appendix: Comparison of Results for the STN and SEARCH Birmingham Sites 

This page deliberately left blank. 

ICF International A-12 VISTAS Meteorological Characterization 

06-046 December 8, 2006 

Appendix B.7 - 320
SUMMARY OF METEOROLOGICAL 

CONDITIONS AND CART RESULTS 

FOR IMPROVE SITES IN NC

Prepared by

Sharon Douglas and Belle Hudischewskyj

ICF International

Appendix B.7 - 321
Characterizing Meteorology

• Objectives:

– Characterize relationship between meteorology, PM2.5, 

visibility, for IMPROVE, STN, and SEARCH sites 

– Evaluate how well meteorological and visibility conditions 

of the 2002 modeling year represents the 2000-2004 baseline period 

Appendix B.7 - 322
Classifying Days using Visibility, 

Meteorology, and PM2.5

• Classification and Regression Tree (CART) analyses

– Classify days based on extinction coefficient– 5 extinction classes defined for each site 

• 20th, 50th, 80th, and 95th percentiles

– 2000-2004 data – 21 IMPROVE, 8 SEARCH, 16 STN sites

Appendix B.7 - 323
Classifying Days Using Visibility, 

Meteorology, and PM2.5

• Classification and Regression Tree (CART) methods 

– Use meteorological parameters at (or near) the site – Use PM2.5 on previous days at regional/upwind sites– CART decision tree sorts days using most influential 

parameters first

– Assign days to “bins” of days with similar meteorology– Several bins assigned to same class

• different combinations of meteorological conditions can lead 

to same extinction

Appendix B.7 - 324
CART Results for Visibility at 

IMPROVE sites 

• Using only meteorological inputs, 65 to 80% of days are 

accurately classified

• Adding PM2.5 on previous day at upwind sites improves 

accuracy of classifying days for visibility to 73-88%

• Optimal CART decision tree has 25-35 bins• Key parameters vary across sites and classes

Appendix B.7 - 325
CART Visibility Analyses – IMPROVE

• In general, poor visibility days are associated with

– High temperatures – High relative humidity– High PM2.5 on the previous day at upwind sites– Low wind speeds near the surface and aloft– Stable morning conditions – Predominant surface wind direction is site specific

• PM2.5 composition on poor visibility days varies by site• Greater variability in conditions leading to good visibility 

Appendix B.7 - 326
NOTES ON SUMMARIES OF 

RESULTS FOR VISIBILITY

• Classification accuracy for visibility combines Categories 2 

& 3, so emphasis is on Category 1 (Best) and 4 & 5 (Worst) days

• References to high, low etc... are used mostly in a relative 

and site specific sense, rather than an absolute sense, to compare and distinguish the characteristics of the poor visibility categories (more detailed descriptions are included in the project report)

Appendix B.7 - 327
CATEGORICAL COMPARISONS FOR 

VISIBILITY FOR GRSM

50

3025201510

T (deg C) YFM (μgm-3)

<45 45-75 75-120 120-180 >=180

Surface Characteristics: All Days (2000-2004)/5 Ex. Coeff. Categories (Mm-1)

43210

WS (m/s)

<45 45-75 75-120 120-180 >=180

0

90

360270180

WD (deg)

<45 45-75 75-120 120-180 >=180

0

80604020

100

RH (%)

<45 45-75 75-120 120-180 >=180

*Knoxville

*

Appendix B.7 - 328
CATEGORICAL COMPARISONS FOR 

VISIBILITY: GRSM

-1

-0.5

0

0.5

1

DT (deg C) Persist

<45 45-75 75-120 120-180 >=180

Upper-Air Characteristics: All Days (2000-2004)/5 Ex. Coeff. Categories

50

1510

850 mb WS (m/s)

<45 45-75 75-120 120-180 >=180

0

90

360270180

850 mb WD (deg)

<45 45-75 75-120 120-180 >=180

*

Appendix B.7 - 329
CART PARAMETER IMPORTANCE 

FOR VISIBILITY: GRSM

*

CART Variable Importance Averaged Scores - Great Smoky 

Mountains

0 20 40 60 80 100

Clouds 

Avg 850 mb w ind direction 

Avg 850 mb w ind speed 

Yesterday's 700 mb w ind direction (PM)

Yesterday's 700 mb w ind speed (PM)

700 mb height difference

Stability 

Avg 850 mb temp 

Rain

Solar radiation

Persistence

Surface w ind direction

Surface w ind speed

Relative humidity at noon

Avg surface temp

Regional avg of yesterday's max PM

Appendix B.7 - 330
COMPOSITIONAL ANALYSIS FOR 

KEY VISIBILITY BINS: GRSM

Great Smoky Mountains Key Visibility Bins: Component Averages

8.006.004.002.000.00

16.0014.0012.0010.00

1 (43) 6 (9) 5 (42) 13 (33) 4 (22) 26 (32) 7 (12) 28 (9) 27 (13) 29 (14) 18 (12) 35 (10) 32 (8) 15 (3)

Class 1 Class 2 Class 3 Class 4 Class 5

Bin No. (No. of Correctly Classified Days)

) Avg. Conc. (μg/m3 ECNO3 OMSO4

Appendix B.7 - 331
SUMMARY OF RESULTS FOR 

VISIBILITY: GRSM

• Classification accuracy: 78%• Poor visibility is associated with

– Moderate to high prior-day PM2.5 (at upwind sites)– Moderate temperatures and high RH– Low wind speeds near the surface and aloft (esp. Category 5)– WSW winds both aloft and W winds near the surface

• PM2.5, temperature, humidity, stability and upper-air 

wind speed parameters important for CART

• Poor visibility regimes are associated with 

– Moderate to high SO4 and low to moderate OM

Appendix B.7 - 332
COMPOSITIONAL ANALYSIS FOR 

KEY PM2.5 BINS: GRSM

Great Smoky Mountains Key PM Bins: Component Averages

8.006.004.002.000.00

16.0014.0012.0010.00

3 (291) 14 (1) 17 (20) 20 (20) 22 (12) 5 (8) 11 (10) 13 (7) 26 (7) 24 (14)

Class 1 Class 4 Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

) Avg. Conc. (μg/m3 ECNO3 OMSO4

Appendix B.7 - 333
CATEGORICAL COMPARISONS 

FOR VISIBILITY FOR LINVILLE 

GORGE

50

3025201510

T (deg C) YFM (μgm-3)

<35 35-70 70-120 120-180 >=180

Surface Characteristics: All Days (2000-2004)/5 Ex. Coeff. Categories (Mm-1)

43210

WS (m/s)

<35 35-70 70-120 120-180 >=180

0

90

360270180

WD (deg)

<35 35-70 70-120 120-180 >=180

0

80604020

100

RH (%)

<35 35-70 70-120 120-180 >=180

*Knoxville

*

Appendix B.7 - 334
CATEGORICAL COMPARISONS 

FOR VISIBILITY: LINVILLE 

GORGE

-1

-0.5

0

0.5

1

DT (deg C) Persist

<35 35-70 70-120 120-180 >=180

Upper-Air Characteristics: All Days (2000-2004)/5 Ex. Coeff. Categories

50

1510

850 mb WS (m/s)

<35 35-70 70-120 120-180 >=180

0

90

360270180

850 mb WD (deg)

<35 35-70 70-120 120-180 >=180

*

Appendix B.7 - 335
CART PARAMETER 

IMPORTANCE FOR VISIBILITY: 

LINVILLE GORGE

*

CART Variable Importance Averaged Scores - Linville Gorge

0 20 40 60 80 100

Clouds 

Recirculation 

Avg 850 mb w ind direction 

Avg 850 mb w ind speed 

Yesterday's 700 mb w ind direction (PM)

Yesterday's 700 mb w ind speed (PM)

700 mb height difference 

Stability 

Avg 850 mb temp 

Rain

Max surface pressure

Persistence

Surface w ind direction

Surface w ind speed

Relative humidity at noon

Avg surface temp

Regional avg of yesterday's max PM

Appendix B.7 - 336
COMPOSITIONAL ANALYSIS 

FOR KEY VISIBILITY BINS: 

LINVILLE GORGE

Linville Gorge Key Visibility Bins: Component Averages

8.006.004.002.000.00

12.0010.00

1 (37) 2 (24) 3 (30) 11 (19) 9 (17) 30 (17) 12 (31) 32 (28) 17 (10) 7 (10) 20 (21) 23 (14) 28 (12)

Class 1 Class 2 Class 3 Class 4 Class 5

Bin No. (No. of Correctly Classified Days)

) Avg. Conc. (μg/m3 ECNO3 OMSO4

Appendix B.7 - 337
SUMMARY OF RESULTS FOR 

VISIBILITY: LINVILLE GORGE

• Classification accuracy: 83%• Poor visibility is associated with

– High prior-day PM2.5 (at upwind sites)– High temperatures and relative humidity– Low wind speeds near the surface and aloft– W(NW) winds aloft; NW to N winds near the surface

• PM2.5, RH, temperature, stability, and upper-air 

wind speed parameters important for CART

• Poor visibility regimes are associated with 

– Moderate to high SO4 and low to moderate OM 

concentrations

Appendix B.7 - 338
COMPOSITIONAL ANALYSIS 

FOR KEY PM2.5 BINS: LINVILLE 

GORGE

Linville Gorge Key PM Bins: Component Averages

8.006.004.002.000.00

14.0012.0010.00

1 (227) 6 (49) 21 (17) 18 (22) 15 (11) 31 (9) 30 (5) 19 (5) 25 (15)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

) Avg. Conc. (μg/m3 ECNO3 OMSO4

Appendix B.7 - 339
CATEGORICAL COMPARISONS 

FOR VISIBILITY FOR LINVILLE 

GORGE

50

3025201510

T (deg C) YFM (μgm-3)

<35 35-70 70-120 120-180 >=180

Surface Characteristics: All Days (2000-2004)/5 Ex. Coeff. Categories (Mm-1)

43210

WS (m/s)

<35 35-70 70-120 120-180 >=180

0

90

360270180

WD (deg)

<35 35-70 70-120 120-180 >=180

0

80604020

100

RH (%)

<35 35-70 70-120 120-180 >=180

*Knoxville

*

Appendix B.7 - 340
CATEGORICAL COMPARISONS 

FOR VISIBILITY: LINVILLE 

GORGE

-1

-0.5

0

0.5

1

DT (deg C) Persist

<35 35-70 70-120 120-180 >=180

Upper-Air Characteristics: All Days (2000-2004)/5 Ex. Coeff. Categories

50

1510

850 mb WS (m/s)

<35 35-70 70-120 120-180 >=180

0

90

360270180

850 mb WD (deg)

<35 35-70 70-120 120-180 >=180

*

Appendix B.7 - 341
CART PARAMETER 

IMPORTANCE FOR VISIBILITY: 

LINVILLE GORGE

*

CART Variable Importance Averaged Scores - Linville Gorge

0 20 40 60 80 100

Clouds 

Recirculation 

Avg 850 mb w ind direction 

Avg 850 mb w ind speed 

Yesterday's 700 mb w ind direction (PM)

Yesterday's 700 mb w ind speed (PM)

700 mb height difference 

Stability 

Avg 850 mb temp 

Rain

Max surface pressure

Persistence

Surface w ind direction

Surface w ind speed

Relative humidity at noon

Avg surface temp

Regional avg of yesterday's max PM

Appendix B.7 - 342
COMPOSITIONAL ANALYSIS 

FOR KEY VISIBILITY BINS: 

LINVILLE GORGE

Linville Gorge Key Visibility Bins: Component Averages

8.006.004.002.000.00

12.0010.00

1 (37) 2 (24) 3 (30) 11 (19) 9 (17) 30 (17) 12 (31) 32 (28) 17 (10) 7 (10) 20 (21) 23 (14) 28 (12)

Class 1 Class 2 Class 3 Class 4 Class 5

Bin No. (No. of Correctly Classified Days)

) Avg. Conc. (μg/m3 ECNO3 OMSO4

Appendix B.7 - 343
SUMMARY OF RESULTS FOR 

VISIBILITY: LINVILLE GORGE

• Classification accuracy: 83%• Poor visibility is associated with

– High prior-day PM2.5 (at upwind sites)– High temperatures and relative humidity– Low wind speeds near the surface and aloft– W(NW) winds aloft; NW to N winds near the surface

• PM2.5, RH, temperature, stability, and upper-air 

wind speed parameters important for CART

• Poor visibility regimes are associated with 

– Moderate to high SO4 and low to moderate OM 

concentrations

Appendix B.7 - 344
COMPOSITIONAL ANALYSIS 

FOR KEY PM2.5 BINS: LINVILLE 

GORGE

Linville Gorge Key PM Bins: Component Averages

8.006.004.002.000.00

14.0012.0010.00

1 (227) 6 (49) 21 (17) 18 (22) 15 (11) 31 (9) 30 (5) 19 (5) 25 (15)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

) Avg. Conc. (μg/m3 ECNO3 OMSO4

Appendix B.7 - 345
CATEGORICAL COMPARISONS 

FOR VISIBILITY FOR 

SWANQUARTER

50

3025201510

T (deg C) YFM (μgm-3)

<40 40-70 70-115 115-175 >=175

Surface Characteristics: All Days (2000-2004)/5 Ex. Coeff. Categories (Mm-1)

43210

WS (m/s)

<40 40-70 70-115 115-175 >=175

0

90

360270180

WD (deg)

<40 40-70 70-115 115-175 >=175

0

80604020

100

RH (%)

<40 40-70 70-115 115-175 >=175

*Norfolk

*

Appendix B.7 - 346
CATEGORICAL COMPARISONS 

FOR VISIBILITY: 

SWANQUARTER

-1

-0.5

0

0.5

1

DT (deg C) Persist

<40 40-70 70-115 115-175 >=175

Upper-Air Characteristics: All Days (2000-2004)/5 Ex. Coeff. Categories

50

1510

850 mb WS (m/s)

<40 40-70 70-115 115-175 >=175

0

90

360270180

850 mb WD (deg)

<40 40-70 70-115 115-175 >=175

*

Appendix B.7 - 347
CART PARAMETER 

IMPORTANCE FOR VISIBILITY: 

SWANQUARTER

*

CART Variable Importance Averaged Scores - Swanquarter

0 20 40 60 80 100

Clouds 

Recirculation 

Avg 850 mb w ind direction 

Avg 850 mb w ind speed 

Yesterday's 700 mb w ind direction (PM)

Yesterday's 700 mb w ind speed (PM)

700 mb height difference 

Stability 

Avg 850 mb temp 

Rain

Max surface pressure

Persistence

Surface w ind direction

Surface w ind speed

Relative humidity at noon

Avg surface temp

Regional avg of yesterday's max PM

Appendix B.7 - 348
COMPOSITIONAL ANALYSIS 

FOR KEY VISIBILITY BINS: 

SWANQUARTER

Swanquarter Key Visibility Bins: Component Averages

8.006.004.002.000.00

10.00

2 (17) 19 (12) 4 (6) 5 (40) 29 (9) 14 (31) 31 (19) 7 (9) 28 (6) 30 (6) 23 (6) 27 (15)

Class 1 Class 2 Class 3 Class 4 Class 5

Bin No. (No. of Correctly Classified Days)

) Avg. Conc. (μg/m3 ECNO3 OMSO4

Appendix B.7 - 349
SUMMARY OF RESULTS FOR 

VISIBILITY: SWANQUARTER

• Classification accuracy: 80%• Poor visibility is associated with

– Moderate prior-day PM2.5 (big jump to Category 5)– Moderate temperatures and high RH– Moderate wind speeds (slight decreasing tendency near sfc)– W winds aloft and SW to W winds near the surface

• PM2.5, RH, pressure and other surface and upper-air 

met parameters important for CART

• Poor visibility regimes are associated with 

– Moderate SO4 and low to moderate OM concentrations

Appendix B.7 - 350
COMPOSITIONAL ANALYSIS 

FOR KEY PM2.5 BINS: 

SWANQUARTER

Swanquarter Key PM Bins: Component Averages

8.006.004.002.000.00

12.0010.00

5 (160) 24 (29) 16 (11) 12 (9) 21 (13) 17 (5) 13 (6) 28 (4)

Class 1 Class 2 Class 3 Class 4

Bin No. (No. of Correctly Classified Days)

) Avg. Conc. (μg/m3 ECNO3 OMSO4

Appendix B.7 - 351