AgDrift Chlorpyrifos Analysis 

Aerial Application (Concentration at 5 foot breathing height)

Tier 2 Agdrift V 2.01 Used With All Defaults Except Active and Non-volatile Rates Based On DAS Error Correction Comments/M

Active (lb ai/a): 6 Non Vol. Rate (lb ai/a): 9

Active (lb ai/a): 4 Non Vol. Rate (lb ai/a): 6

Active (lb ai/a): 2.3 Non Vol. Rate (lb ai/a): 3.45

Active (lb ai/a): 2 Non Vol. Rate (lb ai/a): 3

Active (lb ai/a): 1 Non Vol. Rate (lb ai/a): 1.5

All scenarions based on 2 gallon per acre spray volume

6 lb ai/ A - Nursery and Orchard Trees (except apple), Tree Fruit, Tree Nuts

Flux Plane 

Distance (ft) ng/L (ppt) ng/m3

Flux Plane 

Distance (ft) ng/L (ppt) ng/m3

0 75 75000 0 55 55000

10 62.5 62500 10 42.5 42500

25 51 51000 25 32.5 32500

50 42 42000 50 25 25000

75 32 32000 75 18 18000

100 26 26000 100 15 15000

125 22 22000 125 12.5 12500

4 lb ai/ A - Nursery and Orchard Trees (except apple), Tree Fruit, Tree Nuts

Flux Plane 

Distance (ft) ng/L (ppt) ng/m3

Flux Plane 

Distance (ft) ng/L (ppt) ng/m3

0 52.5 52500 0 37.5 37500

10 44 44000 10 29.5 29500

25 37 37000 25 23 23000

50 30 30000 50 18 18000

75 23 23000 75 14 14000

100 20 20000 100 12 12000

125 17 17000 125 9.5 9500

2.3 lb ai/ A - Citrus Greening

Flux Plane 

Distance (ft) ng/L (ppt) ng/m3

Flux Plane 

Distance (ft) ng/L (ppt) ng/m3

0 33 33000 0 23 23000

10 27 27000 10 18 18000

25 23 23000 25 14 14000

50 19 19000 50 12 12000

75 16 16000 75 9 9000

100 13 13000 100 8 8000

125 12 12000 125 7 7000

Medium to Coarse Droplet Size Coarse to Very Coarse Droplet

Medium to Coarse Droplet Size Coarse to Very Coarse Droplet

Medium to Coarse Droplet Size Coarse to Very Coarse Droplet
2 lb ai/ A - Nursery and Orchard Trees (except apple), Tree Fruit, Tree Nuts

Flux Plane 

Distance (ft) ng/L (ppt) ng/m3

Flux Plane 

Distance (ft) ng/L (ppt) ng/m3

0 29 29000 0 20 20000

10 24 24000 10 16 16000

25 21 21000 25 13 13000

50 18 18000 50 11 11000

75 14 14000 75 8 8000

100 13 13000 100 7 7000

125 11 11000 125 6 6000

1 lb ai/ A - Alfalfa, Asparagus, Sorghum, Strawberry, Sugarbeet

Flux Plane 

Distance (ft) ng/L (ppt) ng/m3

Flux Plane 

Distance (ft) ng/L (ppt) ng/m3

0 16 16000 0 11 11000

10 13 13000 10 8 8000

25 12 12000 25 8 8000

50 10 10000 50 6 6000

75 9 9000 75 5 5000

100 8 8000 100 4 4000

125 7 7000 125 3 3000

Coarse to Very Coarse Droplet

Medium to Coarse Droplet Size

Medium to Coarse Droplet Size

Coarse to Very Coarse Droplet
 Error Correction Comments/Meeting:
AgDrift Chlorpyrifos Analysis 

Acute HEC 2480000 LOC = 300

Aerial Application (Concentration at 5 foot breathing height)

Flux plane air concentrations represent 1 hour TWA values

Amortization accounts for anticipated dissipation over time and lack of active exposure source

Dissipation rate (fraction retained per hour): 0.25

Concentrations based on Agdrift Tier 2 and DAS Error Correction Comments

Medium/Coarse Droplets Coarse/Very Coarse Droplets Medium/Coarse Droplets Coarse/Very Coarse Droplets

ng/m3 ng/m3 ng/m3 MOE ng/m3 MOE

0 75000 55000 46875 53 34375 72

10 62500 42500 39063 63 26563 93

25 51000 32500 31875 78 20313 122

50 42000 25000 26250 94 15625 159

75 32000 18000 20000 124 11250 220

100 26000 15000 16250 153 9375 265

125 22000 12500 13750 180 7813 317

0 52500 37500 32813 76 23438 106

10 44000 29500 27500 90 18438 135

25 37000 23000 23125 107 14375 173

50 30000 18000 18750 132 11250 220

75 23000 14000 14375 173 8750 283

100 20000 12000 12500 198 7500 331

125 17000 9500 10625 233 5938 418

0 33000 23000 20625 120 14375 173

10 27000 18000 16875 147 11250 220

25 23000 14000 14375 173 8750 283

50 19000 12000 11875 209 7500 331

75 16000 9000 10000 248 5625 441

100 13000 8000 8125 305 5000 496

125 12000 7000 7500 331 4375 567

0 29000 20000 18125 137 12500 198

10 24000 16000 15000 165 10000 248

25 21000 13000 13125 189 8125 305

50 18000 11000 11250 220 6875 361

75 14000 8000 8750 283 5000 496

100 13000 7000 8125 305 4375 567

125 11000 6000 6875 361 3750 661

0 16000 11000 10000 248 6875 361

10 13000 8000 8125 305 5000 496

25 12000 8000 7500 331 5000 496

50 10000 6000 6250 397 3750 661

75 9000 5000 5625 441 3125 794

100 8000 4000 5000 496 2500 992

125 7000 3000 4375 567 1875 1323

1 lb ai/ A 

Flux Plane Distance (ft)

1 Hr Concentrations From AgDrift Results Based On 2 Hr Amortized Concentration

2.3 lb ai/ A - Citrus (Greening)

2 lb ai/ A 

6 lb ai/ A 

4 lb ai/ A