Department of Pesticide Regulation
 

Mary-Ann Warmerdam M E M O R A N D U M 	 Arnold Schwarzenegger Director	 Governor 

TO: 	 Randy Segawa, Environmental Program Manager I 
 

Environmental Monitoring Branch 
 

FROM: 	 Bruce Johnson, Ph.D., Research Scientist III Original signed by
 

Environmental Monitoring Branch 
 

(916) 324-4106 

DATE: September 24, 2007 

SUBJECT: RECALCULATION OF 1,3-DICHLOROPROPENE EMISSION FACTORS 

A previous memorandum (Johnson 2006) calculated emission factors for shank-injected 

1,3-dichloropropene based on two deep and two shallow flux studies (Gillis and Dowling, 

1998; Knuteson et al., 1992; Knuteson et al., 1995). The method required assumption of a 

linear relationship between depth and cumulative flux. With that assumption, the four studies 

were combined to estimate a flux at 12 inches and 18 inches of depth. A simpler approach, and 

one not requiring the assumption of a linear relationship, is to divide the four studies into two 

groups: shallow and deep and take simple averages for the two groups. 

Table 1 provides the revised calculations and along with the previously values for comparison. 

The result increased the shallow factor from 61% to 65% and increased the shallow with water 

treatments from 41% to 44%. The deep injection method decreased from 41% to 26%. The 

recalculation does not affect the drip method. 

Table 1. Shank injection methods for 1,3-d, recalculation of emission factors. 

Percentage 

based on 

Johnson Revised 

Method (2006) Percentages Notes: 

Shallow injection 61 65 Based on average of 2 shallow studies 

Shallow injection w/ 3 water treatments 41 44 Based on reducing shallow broadcast by 33% 

Deep injection w/ high permeability tarp or no tarp-broadcast 41 26 Based on average of 2 deep studies 

1001 I Street • P.O. Box 4015 • Sacramento, California 95812-4015 • www.cdpr.ca.gov 

A Department of the California Environmental Protection Agency 

Printed on recycled paper, 100% post-consumer--processed chlorine-free. 
Randy Segawa 

September 24, 2007 

Page 2 

References 

Gillis, Matthew J. and Kathryn C. Dowling. 1998. Effect of broadcast and row application 

methods on 1,3-dichloropropene emissions. Dow AgroSciences LLC, 9330 Zionsville Rd., 

308/2E. Indianapolis, IN. Bolsa Research Project #:BR730, Dow AgroSciences Study ID #: 

HEA95177. 

Johnson, Bruce. 2006. Memorandum to Randy Segawa dated November 30, 2006 on Calculation 

of emission potential factors for 1,3-dichloropropene for five areas for periods from May 1 

through October 31. 

Knuteson, James A., David G. Petty, and Bradley A. Shurdet. 1992. Field volatility of 

1,3-dichloropropene in Salinas Valley California. DowElanco, Midland, MI. 

Knuteson, J.A., H.E. Dixon-White and D.G. Petty. 1995. Field volatility of 

1,3-dichlororopropene in San Joaquin Valley California. DowElanco ENV93063. 
APPENDIX 3 

Application Method Adjustment Factors and 

Method Use Fractions for 1,3-Dichloropropene 

Appendix A-55 A-55
Department of Pesticide Regulation

Mary-Ann Warmerdam M E M O R A N D U M Arnold Schwarzenegger Director Governor 

TO: Randy Segawa, Agriculture Program Supervisor IV 

Environmental Monitoring Branch 

FROM: Bruce Johnson, Ph.D., Research Scientist III Original signed by 

Environmental Monitoring Branch 

(916) 324-4106 

DATE: November 30, 2006 

SUBJECT: CALCULATION OF EMISSION POTENTIAL FACTORS FOR 

1,3-DICHLOROPROPENE FOR FIVE AREAS FOR PERIODS FROM 

MAY 1 THROUGH OCTOBER 31

Introduction 

Emissions of volatile organic compounds from pesticide applications are estimated by the 

Department of Pesticide Regulation as follows: 

VOC emitted (lbs) = EP * lbs product applied (1) 

The Emission Potential (EP) is that fraction of a product that is assumed to contribute to 

tropospheric VOCs. Several methods have been used to measure or estimate EPs for different 

pesticide products. For many fumigants, including 1,3-dichloropropene (1,3-d) products, EPs 

have historically been assumed to be 100%. However, several studies have demonstrated that a 

portion of applied 1,3-d does not volatilize from soil after application. The purpose of this 

memorandum is to estimate EP for 1,3-d in five California regions during the May–October 

ozone season. 

Background 

The fumigant 1,3-dichloropropene was suspended in April of 1990 when high air concentrations 

were found in Merced. Reintroduction occurred in 1995 following field studies which measured 

1,3-d emissions. Initially, 1,3-d was applied only by shank injection. However, a subsequent 

formulation of 1,3-d called InLine was brought to market which was applied by drip irrigation. 

In this memorandum, I will first discuss development of factors for shank injection and then 

development of factors for drip application. 

Approach 

This approach relies on two strands of analysis, which are combined to calculate the final factor. 

The first strand examines the injection and drip application methods and associated flux studies 

to estimate a non-summer and summer flux factor. The second strand examines by region the 

Appendix A-56 A-56

1001 I Street • P.O. Box 4015 • Sacramento, California 95812-4015 • www.cdpr.ca.gov 

A Department of the California Environmental Protection Agency 

Printed on recycled paper, 100% post-consumer--processed chlorine-free. 
Randy Segawa 

November 30, 2006 

Page 2 

pounds of 1,3-d used in order to develop weights for combining the flux factors. The final 

calculation consists of the use-weighted aggregate factor (EP) for each region. You provided me 

with a list of four regions to calculate in addition to the San Joaquin region which I originally 

calculated. The five regions are San Joaquin Air Basin, Sacramento Metro, Southeast Desert, 

Ventura, and South Coast. 

Shank injection 

A 1,3-d flux study (Knuteson et al. 1992) conducted as part of the research effort yielded a 

volatilization loss of 25%. In this study, 1,3-d was injected at a depth of 18 inches. Because this 

study was done under relatively cool conditions during fall, an ad hoc factor of 40% (40/25=1.6x) 

was considered more appropriate for emissions from summer time applications when warmer 

conditions may cause greater losses. 

Several memoranda were written presenting simulation work and discussing the concept of 

regulating 1,3-d by restricting use on a township basis (Johnson 1995ab, 1996). For injection 

depths shallower than 18 inches, a linear interpolation scheme was used. This scheme 

assumed 100% volatilization at the soil surface (depth = 0) and 35% at a depth of 18 inches 

(Johnson, 1996). The 35% volatilization fraction was a weighted average of the summer and 

non-summer application volatilization fractions. 

Current approaches to estimating volatilization flux for injected 1,3-d assume either linear or 

nonlinear relationships between flux and injection depth (Cryer, 2005). Gan et al. (1998) 

reported flux data from laboratory experiments using 1,3-d. Those data demonstrate a linear 

relationship between volatilization fraction and injection depth for uncovered treatments at 

20, 30, and 40 cm injection depths. 

Four field studies of 1,3-d flux from injection application are depicted in Figure 1 along with 

the linear interpolation line from 100% to 40% over 0 to 18 inch depth. The cumulative 

volatilization fraction calculations are based on measured flux from commercial-sized field 

applications. 

Field studies typically display high variability. In our own experience, based largely on 

back-calculated values from commercial-sized field applications of methyl bromide, coefficients 

of variation ranged from 38% to 52% for 24-hour flux fractions over 3 kinds of applications 

(Barry 1999). Consequently, in consideration of what I believe would be relatively high variation 

(in the vertical direction) in field-to-field estimates inherent to Figure 1 and the observed linear 

relationship between volatilization fraction and depth observed in the laboratory (Gan et al. 1998), 

a linear interpolation is probably a reasonable representation of the depth-flux relationship as a 

generalization of commercial applications. 

Appendix A-57 A-57
Randy Segawa 

November 30, 2006 

Page 3 

P

ercent E

mission 

100 

90 

80 

70 

0 5 10 15 20 25 

Measured Values 

Interpolation scheme 

A 

B 

C 

60 

50 

40 

30 

20 

Depth (inches) 

Figure 1. Measured values and interpolation scheme. A (Knuteson et al. 1992), 

B (two points, Gillis and Dowling (1998)), C (Knuteson et. al. 1995). 

Calculation of non-summer and summer injection factor 

The volatilization factors are based on the following assumptions: 

1. Linear interpolation can be used to estimate flux where 100% is assumed to volatilize at the 

surface and a study provides emissions based on the study injection depth. 

2. The California Data Management System (CDMS) database contains two types of entries for 

injection: “Injected 18 inches or deeper” and “Injected 12 to 17 inches.” I will use an 18 inch 

depth for the deep injection and a 12 inch depth for the shallow injection. 

3. Summer emissions are 1.6x higher than non-summer emissions. 

The four studies depicted in Figure 1 are provided in tabular form (Table 1). The first column 

is the fraction volatilized during the study. The third column is the depth of injection. To 

interpolate for each study, a line is constructed running through (depth, fraction volatilized) from 

the study and (0 inch depth, 100% volatilized). The last column in Table 1 shows the calculated 

volatilization fraction at 18 inch depth using linear interpolation based on each study’s results. 

Equation 2 displays the formula used to calculate these entries. 

Appendix A-58 A-58
Randy Segawa 

November 30, 2006 

Page 4 

Table 1. Four flux studies of 1,3-d shank application. Linear 

Injection Interpolation 

depth in to 18" Depth 

Fraction study Bedded or Date of Fraction 

Volatilized Method (inches) not Application Reference Volatilized 

Gillis and 

Dowling 

0.65 Shank 14 no bed 10/29/1995 1998 0.55 

Gillis and 

Dowling 

0.65 Shank 12 bed 11/15/1995 1998 0.48 

Knuteson et 

0.26 Shank 20-22 bed 5/5/1993 al. 1995 0.37 

Knuteson et 

0.25 Shank 18 no bed 9/25/1991 al. 1992 0.25 

Average 0.41 

(1.0 − F ) = (0 − Di

D

)

i F ( ) +1.0 (2) 18 18 

In equation 2, F18 is the estimated fraction volatilized at 18 inch depth, FDi is the fraction 

volatilized in study i at depth Di. The average volatilization factor at 18 inches was 0.41. I have 

ignored that two of the studies were bedded and two of the studies were broadcast. Incorporating 

the resulting average fraction at 18 inches into new equation results in 

FD 

(1.0 − 0.41) = ( ) D +1.0 = −0.033D +1.0 (3) (0 1− 8 )

This equation applies from 0 to 18 inches depth of injection for non-summer shank applications. 

The symbols are FD=fraction of applied active ingredient volatilized at depth, D, in inches. Using 

equation 3 at 12 inches depth yields a fraction of 0.61[ = −0.033*12 +1.0]. 

Appendix A-59 A-59
Randy Segawa 

November 30, 2006 

Page 5 

Since these studies were all conducted outside of summer season, the corresponding 

volatilization fraction during summer applications would be (1.6)*0.41=0.656, for the 18 inch 

depth and (1.6)*0.61=0.97 for the 12 inch depth. 

Calculation of non-summer and summer drip factor 

Two studies of tarped drip application were conducted (Table 2). Study results were mutually 

consistent and 29% of the applied 1,3-d volatilized. One study (Knuteson et al. 1999) was 

Table 2. Two flux studies of 1,3-d drip application. 

Fraction Bedded or Date of 

Volatilized Method Tarped not Application Reference 

Knuteson et 

0.29 Drip Yes bedded 10/2/1998 al. 1999 

Wesenbeeck 

and Phillips 

0.29 Drip Yes bedded 12/6/1999 2000 

conducted in Salinas, California, while the other was conducted in Douglas, Georgia. Applying 

the 1.6 summer factor to 0.29 resulted in a factor 0.46 for summer drip. For drip formulations 

(Telone EC, InLine) about 6% by product weight consists of inert ingredients. No applications 

using Telone EC were listed in the 2004 CDMS database. 

Table 3 summarizes the drip 

and shank volatilization Table 3. Factor summary 

factors. Shallow shank Drip Shallow Shank Deep Shank 

Non-summer 0.290 0.610 0.410 

refers to a 12 inch depth, Summer 0.464 0.970 0.656 

while deep shank refers to 

an 18 inch depth (or deeper). 

Drip refers to tarped drip applications. Current label requirements mandate tarping for drip 

applications. 

Calculation of non-summer and summer use weights for five basins 

The next step was to determine the fraction of pounds applied in the five basins for the three 

application methods, split between non-summer and summer months from May 1 through 

October 31. Summer was defined as from June 21 to Sept 21 inclusive. These factors were 

estimated using CDMS report of 2004 1,3-d use data. The fractions were based on pounds of 

1,3-d applied. Applications listed in the CDMS system are classified by method. The five regions 

and associated counties that I used are San Joaquin (Fresno, Kern, Kings, Madera, Merced, 

San Joaquin, Stanislaus, and Tulare); Sacramento Metro (Sacramento, Solano, Yolo, Placer, and 

Appendix A-60 A-60
Randy Segawa 

November 30, 2006 

Page 6 

El Dorado); Southeast Desert (Riverside and San Bernardino); Ventura (Ventura); South Coast 

(Los Angeles and Orange). The pounds were normalized to the total for each region. The regions 

are clearly varied in the use patterns ranging from the Sacramento-Metro region where 1,3-d is 

applied mostly as deep shank in non-summer to the south coast region which is all drip during 

the summer. 

Table 4. Regional use weights for non-summer and method of application 

for 1,3-d. 

Drip Shallow Shank Deep Shank 

Sacramento-Metro Non-summer 0.000 0.000 0.820 

Summer 0.000 0.000 0.180 

SE Desert Non-summer 0.122 0.019 0.000 

Summer 0.839 0.019 0.000 

Ventura Non-summer 0.210 0.022 0.036 

Summer 0.733 0.000 0.000 

San Joaquin Non-summer 0.002 0.004 0.466 

Summer 0.000 0.010 0.518 

South Coast Non-summer 0.000 0.000 0.000 

Summer 1.000 0.000 0.000 

Calculation of regional emission potentials for 1,3-d volatilization 

The calculation of the factors for each region was 

accomplished by multiplying the method factors in Table 5. Regional emission 

Table 3 by the corresponding use weights in Table 4 potentials for 1,3-d. 

within each region and adding the resulting products Emission 

Potential (Table 5). For example, in the Sacramento-Metro region, Sacramento-Metro 0.45 

there were no drip or shallow shank applications. Hence SE Desert 0.46 

the use weights were zero for drip and shallow shank. Ventura 0.43 

The emission potential therefore was calculated as San Joaquin 0.54 

0.41*0.82+0.656*0.18=0.454. The emission potentials South Coast 0.46 

ranged from 0.43 to 0.54. 

cc: Kean S. Goh, Ph.D., Agriculture Program Supervisor IV 

Terrell Barry, Ph.D., Research Scientist III 

Appendix A-61 A-61
Randy Segawa 

November 30, 2006 

Page 7 

References 

Barry, Terri Ph.D. 1999. Memorandum to Randy Segawa on methyl bromide emission ratio 

groupings dated December 2 1999. 

Cryer, Steven A. 2005. Predicting soil fumigant air concentrations under regional and diverse 

agronomic conditions. Journal of Environmental Quality 34:2197-2207. 

Gan, J., S.R. Yates, D. Wang, and F.F. Ernst. 1998. Effect of application methods on 

1,3-dichloropropene volatilization from soil under controlled conditions. Journal of 

Environmental Quality 27:432-438. 

Gillis, Matthew J. and Kathryn C. Dowling. 1999. Effect of broadcast and row application 

methods on 1,3-dichloropropene emissions. Dow AgroSciences LLC, 9330 Zionsville Road, 

308/2E. Indianapolis, Indiana. Bolsa Research Project #:BR730, Dow AgroSciences Study 

Identification number: HEA95177. 

Johnson, Bruce Ph.D. 1995a. Memorandum to John S. Sanders, Ph.D., on Proposal to regulate 

1,3-d using township/range cap. December 7, 1995. 

Johnson, Bruce Ph.D 1995b. Memorandum to Ronald J. Oshima on Calculation of air 

concentrations at various township cap levels and comparison to previous simulation study 

results for 1,3-D. December 20, 1995. 

Johnson, Bruce Ph.D. 1996. Memorandum to John S. Sanders, Ph.D., on Derivation of depth 

factors to apply to standard gallons of 1,3-dichloropropene for determining township gallons 

totals. January 16, 1996. 

Knuteson, James A., David G. Petty, and Bradley A. Shurdet. 1992. Field volatility of 

1,3-dichloropropene in Salinas Valley, California. DowElanco, Midland, Michigan. 

Knuteson, J.A., H.E. Dixon-White, and D.G. Petty. 1995. Field volatility of 

1,3-dichlororopropene in San Joaquin Valley, California. DowElanco ENV93063. 

Knuteson, J.A., S.C. Dolder, and J.P. Mueller. 1999. Field volatility of 1,3-dichloropropene and 

chloropicrin from shallow drip irrigation application of Telone C-35 EC to strawberry beds with 

VIF tarp–Interim report. May 28, 1999. Dow AgroSciences LLC, Indianapolis, Indiana. 980070 

(GH-C 4918). 

Appendix A-62 A-62
Randy Segawa 

November 30, 2006 

Page 8 

Wesenbeeck, I. Van and A. M. Phillips. 2000. Field volatility of 1,3-dichloropropene and 

chloropicrin from surface drip irrigation application of In-Line to vegetable beds under 

polyethylene tarp. Global Environmental Chemistry Laborator–Indianapolis Lab, 

Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, Indiana 46268-1054. 

Study identification number: 990072. 

Appendix A-63 A-63