# Department of Pesticide Regulation

Mar y -A nn W a r m erdam 

# M E M O R A N D U M Arnold Schwarze negger 

# Director Go v e rno r



# TO: John S. Sanders, Ph.D., Chief

Environm ental Monitoring Branch

FROM: Terrell Barry, Ph.D., Re search Scie ntist III Original signed by

Frank C. Spurlock, Ph.D., Research Scientist III Original signed by

Randy Segawa, Environm ental Program Manager I Original signed by

Environm ental Monitoring Branch

(916) 324-4137

DATE: Septem ber 29, 2007

SUBJEC T: PESTICIDE VOLATILE ORGANI C COMP OUND EMIS SION ADJUSTMENT S

FOR FIEL D CONDITIONS AND ES TIMATED VOLATILE ORGANIC

COMPOUND REDUCTIONS–REVISED ESTI MATES

I. Summary

The purpose of this m e morandum is to develop refined em ission adjustm e nt factors to account

for the effect of application m e thod on vol atile organic com pound (VOC) em issions from

pesticides, with particular em phasis on fum i gants, and to es tim a te the VOC reduction s associa t ed

with changes to fum i gant application m e thods . Each year, the Departm e nt of Pesticide

Regulation (DPR) updates an inventory of pe sticide VOC e m issions for May–October for

specified areas and com p ares the em issions on a re lative basis to 1990 or 1991 as the base year.

Prior to 2007, DPR assum e d 100% of applied fum i gants volatilize to the air. Field monitoring

data shows that fum i gant em issions are less than 100% and vary with application m e thod.

There are several do zen field stud ies that m easur ed fum i gant em issions. Em issions vary from

9 to 100% of the am ount applied, depending on th e fum i gant and application m e thod. However,

data is not available for all application m e thods in current use or in use during the 1990/91 base

year. W h en no data is available, em issions have b een estim a ted with surro gate data. In addition

to em ission estim ates associated with each app lication m e thod, DPR has estim ated th e frequency

with which the various application m e thods we re used during 1990/91 ba se year, as well as

currently. R e gistrant data and pesticide use re po rts (PURs) were used for these es tim ates.

DPR used the em issions for each app lication m e thod, and the frequency with which the various

application m e thods are used to adjust its VOC em ission invent ory, as well as to estimate the

possible em ission reductions that would result from further change s to application m e thods. This

analysis shows that application m e thod change s between 1990/91 and 20 04 are insufficient to

achieve the required VOC reductions in at least one of the targeted areas. While application

m e thod changes since 1990/91 have lowered em i ssion rates, increased fum i gant use more

100 1 I Street • P.O. Box 4015 • Sacramen to, Californ i a 9 581 2-40 15 • www

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A Depart m e n t of the California En vironm ent al Prot ection Agency

Prin te d o n re cycled p a p e r , 10 0 % p o s t-consu m e r--p ro ce sse d ch lorin e

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# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 2

than offsets the application m e thod reductions. More over, even if all fum i gant applications used

“low-em i ssion” m e thods, the VOC reductions woul d be insufficient to achieve the required

levels in at least one area. Lim its on fum i gant VOC e m issions m a y be needed during

May–October to ensure the requ ired VOC reductions are achieved.

DPR published its initia l estim a tes of em issi ons in a m e morandum dated April 6, 2007. This

m e morandum updates and revises th ose initial es tim ates based on recen tly subm itted data, and

comments (both public and scientific p eer review) on the April 6 m e m o randum

.

II. Backgro und

Pesticide V O Cs can contribute to the for m ati on of ground-level ozone, which when present in

high concentrations is harmfu l to hum an health and vegetation. The federal Clean Air Act

requires each state to su bm it a state im plem en tation plan (SIP) for achieving and m a intaining

federal am bient air quality standards, includi ng the ozone standard. In 1994, California’s Air

Resources B o ard and DPR developed a SIP elem en t to track and reduce pe sticidal sources of

VOCs in five regions that do not m eet the 1-hour ozone standard (ozone nonattainm e nt areas):

Sacram ento Metro, San Joaquin Valley, South east Desert, Ventura, and S outh Coast. On

February 21, 2006, the U.S. District Court (Easte rn District of California) ordered DP R to

im ple m ent regulations by January 1, 2008, to ach ieve the VOC e m ission reduction goals. DPR

regulation 07-002 com p lies with this order.

In acco rdan ce with th e 1994 SIP, DPR developed a m e thod to track p e sticide VOC em issions

(VOC e m ission inventory). Each year, DPR estim a tes pestic ide VOC emissions f o r

May–October in each nonattainm e nt area and compares the em issions on a relative basis to

1990 or 1991 as the base year. DPR initiated m a jor revisions to the pesticide VOC e m i ssion

procedures in 2002 (Spurlock, 2002a). Num e rous updates and im prove m e nts to the VOC

inventory calculation procedur es have been m a de since that tim e (Spurlock, 2002b, 2004, 2005,

2006; Roush, 2006). The revisions have im prove d the accu racy of DPR’s VOC inventory

relative to earlier versio ns (e.g., Spurlock, 2002c).

Prior to 2007, the potential em ission for a pesticide application was calculated as:

VOC e m ission (pounds) = pounds pesticide prod uct applied x em ission potential (EP)

where EP is the EP of the pesticide product. EP is a m easure of the VOC content of a product.

However, addition a l factors beyond product com position affect em issions under actual use

conditions. In recognition of this, the 1994 pestic ide elem ent of California’s SIP contains a

provision for incorporating new knowledge into pe sticide V O C e m issions estim ation procedures.

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 3

“The 1990 baselin e year and subsequ e nt year estimates may be furth e r adjusted by add itiona l

VOC Emission Factors if additional information becomes availabl e regarding the reactivity of

compounds, the impact of temperature, moisture , deposition substrate, method of application,

and other fa ctors. Any a dditiona l V O C Emission Factor(s) will be pesticide product specific.”

(DPR, 1994). 1



# Fum i gants are am ong the highest VOC contributors due to both their high levels of use and

their high-E P s. For the fum i gants 1,3-dichlo ropropene (1,3-D), chloropicrin, and m e thyl

brom ide EPs of 100% are assum e d. Thus, the VOC estim ation procedures assum e d that all

of these applied fum i gants are ev entu ally rele ased to the troposphere . In the case of

m e ta m

- sodium and N- methyl dithiocarbam at e (metam -potassium ) products, EPs assum e

100% conversion to m e thyl isothiocyanate (M IT C) followed by eventual release of 100%

of MITC to the air. Sim ilarly, for products containing sodium tetrathiocarbonate, EPs assum e

100% conversion to carbon disulf ide followed by release of 100% of carbon disulfide to the

air. DPR has conducted num e rous fum i gant fiel d monitoring studies over the last 15 years

(e.g. <http://www.cdpr.ca.gov/docs/dprdocs/m e t hbrom /pubs.h tm >). Other researchers have

also published fumigant field study results in peer-reviewed literature. Those studies

demonstrate that the assumption of 100% fumigant emission to the air is inaccurate in most

cases. This memorandum describes development of emission adjustment factors accounting

for the effect of application method on VOC em issions from pesticides, with particular

emphasis on fumigants. Using application method adjustment factors, the potential emission

for a pesticide application is calculated as:

VOC e m ission (pounds) =

pounds product applied x EP x appli cation m e thod adjustm e nt factor

The fum i gant application m e thod adjustm e nt factors developed here are expressed as a

proportion o f the am ount of applied fum i gant that is em itted to the air. Th e adjus t m e nt factors

are application m e thod- and fum i gant-specific, based on m easured data, and yield m o re refined

estim ates of fum i gant VOC em issions than prev ious assum p tions. Sec tio n III de scrib e s the

available em ission data and developm ent of th e application m e thod adjustm e nt factors. DPR

regulation 07-002 refers to the application m e t hod adjustm e nt factor as an “em ission rating.”

In California, all agricultural and commercial pesticide applications m u st be reported. The

county agricultural com m i ssioners and DPR compile these PURs into a database. DPR uses

pounds of product applied record ed in this data base to calculate the VOC em issions for each

pesticide ap plica tion inc l uded in the pestic ide V O C e m ission inventory, as shown in the

equations above. Specific appli cation m e thods are not recorded on PURs. Therefore, a second

1 

# O n Fe br ua ry 2 1

, 2 0 0 6

, t h e U. S.- Di st ri ct C o urt (East e r n Di st ri ct of C a l i f o r ni a) o r dere d DPR t o use t h e 1 9 9 1

inve ntory as a surrogate fo r t h e 1990 baseline year.

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 4

adjustm e nt is needed to account for the use of each fum i gant application m e thod. Sec tion IV

describ e s th e pounds of product app l ied associat ed with each fum i gant application m e thod

(m ethod use fraction). DPR regulation 07-002 co ntains provisions to include m e thod of

applic ation f o r f i eld f u m i gations in th e PURs, so the procedu r e outlined in Section IV will not b e

used in the future.

W ithout the application m e thod adjustm e nt fact ors, fum i gants account fo r m o re than 50, 80, and

90% of the pesticide V O C e m issions in the Sa n Joaquin Valley, Southeas t Desert, and Ventura

nonattainm e nt areas, respectively. Moreover, th ese are the 3 nonattainm e nt areas where DPR

does not currently achieve the 20% pesticide V O C reduction of the 1991 base year required by

the U.S. District Court order. DPR is considerin g two regulation strategies to achieve pesticide

VOC reductions from fum i gants, particularly in the nonattainm ent areas. One strategy is to

require use of “low-em i ssion” fum i gant applic ation m e thods and/or prohibit certain “highem ission” fum i gant application m e thods. A s econd strategy is to establish lim its on VOC

em issions from fum i gants within the nonattainment areas. R e gulations that incorporate one or

both of thes e strateg i es will be effective in 2008. Section V asse sses thes e regulatory strategies

by: (1) estimating the pesticide VOC em issions for the 1990 /9 1 base year for each nonattainm e nt

area, with the applicat ion m e thod and m e thod use fraction adju stm e nt factors; (2) estim ating the

VOC reductions that would have occurred if lo w-em ission fum i gant application m e thods had

been used in 2004 for each nonattain m ent area; and (3) estim ating the limit on fum i ga nt

em issions in each nonattainm e nt area that woul d achieve the VOC e m ission reduction s required.

III. Estimates of Volatile Organic Co mpound Emissions Under Field Conditions

(Application Method Adjustment Factors)

In this context, an application m e thod adjust m e nt factor (em i ssion ra ting in DPR regulation

07-002) is th e em issions of fum i gant to the ai r un der field con d itions, expressed as a p r oportion

(percentage) of applied fum i gant, and is fum i gant- as well as app lication m e thod-specific.

Fum i gant em issions have been m easured with se veral m e thods, both in the laboratory and in the

field. Fum i gant em ission under fi eld conditions is a com p lex pro cess that likely varies with

m e thod of a pplication, soil characteristics (e.g., part icle size, moisture, or ganic content), weather

conditions, and other factors. Due to this com p lexity, laboratory m easurem ents m a y not provide

an accurate estim ate of fum i gant em issions under field conditions. Therefore, DPR relies alm o st

exclus ively on f i eld m e asurem ents to estim ate emissions. Add ition a lly, DP R prescrib es m a ny of

the application procedures and equipm ent used for the m onitoring st ud ie s as regu lato ry

requirem e nts. For example, DPR prescrib es r e q u irem ents f o r m a xim u m applic ation r a te,

applic ation depth, ta rpa u lin typ e , so il m o isture , and other critical param e ters based on

application equipm ent, procedur es, and conditions of the m o nitoring studies. These param e ters

are summ arized here, and full descriptions are provided in the or iginal study reports.

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 5

The reason DPR has not incorporated application m e thod adjustm e nt factors previously is the

need to estim a te e m issions using a consistent process for the 1990/91 base year as well as

currently. D u e to exposure concerns, fum i gant application m e thods changed substantially

beginning in 1993, and very few fiel d studies have m easured fum i ga nt em issions associated with

application m e thods prior to this date. This se ction summarizes the available em ission data and

the assum p tions used to estim ate em issions for methods that have no data.

A. Methyl Bromide

DPR proposes application m e thod adjustm e nt fact ors for three m a in groups of m e thyl brom ide

field application m e thods: m e thods that use trac tor shanks to inject m e thyl brom ide into

pre-form ed beds and are covered with a tarpaulin , m e thods that use trac tor shanks to inject

m e thyl brom ide into flat fields (broadcast) and are covered with a tarpaulin, and m e thods that

use tractor shanks to inject m e t hyl brom ide into flat fields (broadcast) without a tarpaulin. In

addition, there are som e nonfield application m e thods. This appro ach is consistent with DPR’s

current regulations for methyl brom i d e.

1. Methyl Bro mide Emission Studies

DPR’s data set includes 30 field studies utilizing current appli cation m e thods (Table 1). DPR’s

analysis of these data shows that the nine bed fum i gations monitored had very high 24-hour

em issions (average of 81% of a m ount applied, coefficient of variation [CV] 38%). The

13 broadcast applications with a tarpaulin show peak 24-hour em issions that average 24% of

the am ount applied (CV 52%). Br oadcast applications without a tarpaulin show peak 24-hour

em issions that average 37% of the amount applie d (CV 47%). Methyl brom ide is injected at

different depths below the soil su rface dependin g on the cro p, with 6–12 inches classified as

shallow injection, and 18–30 inches classified as deep injection. Analysis of the data

(Barry 1999) shows that depth of application had no significant effect on the highest 24-hour

em issions. While in concept there should be a de pth effect, it is like ly in practice that

applic ation

- to-applicatio n variab ility is too large to detect that effect.

Table 1 classifies m e thyl brom ide application m e thods by the type of tractor configurations and

includes bed/broadcast, tarpaulin type, chisel type, and injection depth. A s required by California

regulations since 2000, bed applica tions refer to fum i gation of pr e-form e d beds, and broadcast

refers to fum i gation of flat fields. When a tarpau lin is used, it m u st be a “high barrier” tarpau lin

that has a perm eability b e tween 5 an d 8 m illiliters m e thyl brom ide per hour, per square m e ter,

per 1,000 parts per m illion of m e thyl brom ide under the tarp aulin at 30 degrees Cels iu s. In m o st

cases, th e tarpaulins are applie d simultaneously with the fumiga nt and are buried under m i ni m u m

am ounts of s o il. Chisel type refers to the type of tractor shank or knife used to inject m e thyl

brom ide beneath th e soil surface. Mo st chis el s are scythe-shap e d, and curv ed forward or

rearward re lative to the direc tion of trave l of the trac tor. A “ N obel plow” chise l ref e rs to

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 6

horizontal v-shaped blades m ounted by a vertical arm to the tool bar. Injection depth refers to

depth from t h e soil su rface of a flat field, or the to p of the bed for a bed ap plication.

Five journal articles contained m e thyl brom ide data m o st appropr iate for developing application

m e thod adjustm e nt factors: Majewski et al. (1995 ), Gan et al. (1996), Ya tes et al. (1996a),

Yates et al. (1996b), and Gan et al. (1997). These articles report either direct flux (em i ssion)

m easure m ents (e.g., aerodynam i c m e t hod) in the field or m easured soil colum n results. Table 2

summarizes these studies and shows em ission es tim a tes for Broadcast Tarp and Broadcast

Nontarp m e thods. Shallow and deep injections are pooled within these two categories due to the

lack of significant difference asso ciated with in jection depth observed in the DPR data set. The

average em i ssion for Broadcast Tarp applicatio n m e thod in these studies is 40%. The average

em ission for Broadcast Nontarp applicati on m e thod in these studies is 66%.

2. Methyl B r omide Application Method Adjustment Factors

The average peak 24-hour em issions for the th ree groups are used as the basis for DPR

application m e thod adjustm e nt factors. Majewski et al. (1995) conclude that about 50% of the

total em issions occur in the first 24 hours for a pplications. Therefore, th e 24-hour em issions from

the DPR data set can reasonably be doubled to provide an estim a te of the application m e thod

adjustm e nt factors. The applic ation m e thod adjustm e nt factor for m e thyl brom ide broadcast

applications with a tarpaulin is 48% (both shallow and deep in jection). T h e application m e thod

adjustm e nt factor for m e thyl brom ide broadcast applications without a tarpaulin is 74% (both

shallow and deep injection). Due to the high 24- hour em issions for bed applications with a

tarpaulin, 100% loss should be a ssum e d. Of the two field studies de sc rib e d in the jou r nal a r ticle s

, Majewski et al. (1995) w a s a joint study with DP R, and its results are accounted for in DPR’s

em ission estim a tes shown in Table 1. The em i ssions m easured in the rem a ining field study

(Yates et al. 1996b) were consis tent with the 13 DPR and regist rant studies of that sam e

application m e thod that are used for the current m e thyl brom ide regulations (Table 1). This last

study has not been included in the determ inatio n of the application m e thod adjustm e nt factors

because it h a s a negligib le effect when gr ouped with 13 other studies, an d to m a intain

consistency between the application m e thod adju stm e nt factors and current m e thyl brom ide

regulations.

The data described support application m e t hod adjustm e nt factors for current fum i gation

m e thods. M e thods in use during 1990/91 were signifi cantly different, particul arly in the types of

tarpau lins th at were us ed . Lo w-density polyethylene tarpaulin s (those that have greater

perm eability than the “high barrier” tarpaulins de scribed abov e) were com m only used in

1990/91. No field data for applications with lo w-density tarpaulin is available. However,

laboratory data shows that these are more perm e a ble th an the tarpau lins c u rrently use d. Due to

the lack of data, the applicati on m e thod adjustm e nt factor for m e thyl brom ide m e thods used in

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 7

the 1990/91 base year are assum e d to have the sam e e m issions as current m e thods without a

tarpaulin (74%). This assum p ti on accounts for the perm eable low-de nsity tarpaulins that were in

use at the tim e.

In 1990/91 as well as cu rrently, m e thyl brom ide ha s uses as a space fum i gant for both structures

and harves ted commodities. Methy l b r om ide e m issions from t h ese application m e thods are

assum e d to be 100% of the am ount applied.

The m e thyl brom ide registrants sub m itted proposed application m e thod adjustm e nt factors to

DPR (Stangellhini 2006a; Appendix 1), based on the Gan et al. (1997) study. Som e of the

registrants’ adjustm e nt factors are sim ilar to those proposed by DPR. However, several are

inconsis ten t with DPR’s analys is of the available data (Appendix 2).

Based on the em ission data shown in Table 1 and the assum p tions discussed above, the

application m e thod adjustm e nt f actors for m e thyl brom ide are:

Shallow inje ction w/ h i g h perm eability tarp or no tarp-broadcast 74%

Shallow inje ction w/ low perm eability tarp-b road cast 48%

Shallow injection w/ high perm eabili ty tarp or no tarp-bed 100%

Shallow injection w/ low perm eability tarp-b ed 100%

Deep injec t ion w/ high perm eability tarp or no tar p -broadc a st 74%

Deep injec t ion w/ low perm eability tarp-bro adca st 48%

Nonfield soil (structu ral/post-harvest) 100%

B. 1,3-Dichloropropene

DPR proposes application m e thod adjustm e nt fact ors for four 1,3-D field application m e thods:

m e thods that use tractor shanks to inject 1,3-D at shallow depths, m e thods that use tractor shanks

to inject 1,3-D at deep depths, m e thods that in clude post-fum i gation water treatm ents for shallow

injection, and chem igation with drip irrigation system s.

1. 1,3-Dichloropropene Emission Studies

Appendix 3 is a revised analysis of six 1,3-D fi eld m onitoring studies. Four studies employed a

shank injection at varying depths and two studi es em ployed drip application. In contrast to

m e thyl brom ide, 1,3-D studies appear to show differing em i ssions with depth of injection, but

standard high-density tarpaulins have little or no effect on 1,3-D e m issions (Yates et al. 2002).

The four shank studies w e re grouped into deep (18 inches or deeper) and shallow (14 and 12

inches) applications and sim p le averages taken of the em ission percenta ge in each group.

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 8

Use of 1,3-D was suspended in early 1990 due to high am bient air concentrations m onitored in

Merced. In r e sear ching m itigation m easures to re duce em issions, the re gistr a nt con ducted a f l u x

study using elevated soil m o isture (Knuteson et al. 1992). This soil m o isture m itigation m easure

is now a part of the sh ank applicatio n m e thodology.

Gao and Trout (2007) used flux chambers to esti m a te e m issions for several chloropicrin and

1,3-D application m e thods, including high-de nsity polyethylene ta rpaulin, high-density

polyethy l en e tarp aulin with pr e-irrigation, s i ngle post-fum i gation water treatm e nt, multip le

post-f u m i gation water tre a tm ents (interm ittent wa ter i ng-in ), a nd virtu a lly im perm eable f ilm

. Those researchers reported probl em s m a intain ing a seal b e tw een the so il and the cha m ber.

Consequently predictions of 1,3-D em ission reduc tions due to post-fum i gation water treatm ents

are subject to considerab le uncertainty becau se th e Gao and Trout (2007 ) study is the only

inform ation available for 1,3-D on this m itigati on m easure. However, redu ctions obs erved in

their study are qualitativel y consistent with dem onstrated re ductions in MITC em iss i ons for

post-f u m i gation water tre a tm ents.

2. 1,3-Dichloropropene Applicatio n Method Adjustment Factors

Appendix 3 summarizes and estim a tes the 1,3-D em i ssions for the application m e thods currently

used, based on the available field studies and the em ission adjustm e nts (application factors)

described in DPR’s recommended conditions for 1,3-D restricted m a terials perm its (DPR 2002).

Field studies for 1,3-D have been conducted during the fall and spring seasons only. DPR’s

recomm ended perm it conditions (2002) include an ad hoc adjustm e nt factor for 1,3-D

applications during the summ er. W e have chosen not to includ e the summer adjus t m e nt factor

for 1,3-D application m e thods in these VOC e m is sion estim a tes for three reasons. One, the

summer adjustm e nt factors are ad hoc, and not ba sed on any scientific da ta or evaluation. Two,

DPR does not use a seasonal adjust m e nt for its regulatory em ission values for any of the other

fum i gant. Three, the revised m e thod for estim a ting VOC e m is sions described here is based on

assigning a single field adjustm e nt factor for each app lication m e thod and fum i gant combination;

a seasonal em ission adjustm e nt would greatly in crease the co mplexity of the VOC calculations.

DPR will assum e that reductions in 1,3-D em issi ons for three post-fum i gation water treatm e nts

are approxim a tely one-third less than an untarpe d shallow injection app lication. The monitoring

data for 1,3-D deep injections show peak em i ssions occurring several days later than other

fum i gants. The tim ing and effect of the pos t-fum i gation water treatm ents for 1,3-D deep

injections is uncertain, and the em issions have not been estim ated. Ot her application m e thods

that app ear to reduce ch loropicrin em issions, su ch as pre-irrigation and virtually im perm eable

film may be problem atic due to labeling requi rements and other factors (Gao and Trout, 2007).

Therefore, these application m e thods are not recomm ended at this tim e

.

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 9

In 1990/91 there were virtually no applicati ons of 1,3-D during the ozone season so no

application m e thod adjustm e nt factors ar e needed for m e thods in those years.

Based on the em ission data shown in Table 3 and the assum p tions discussed above, the

application m e thod adjustm e nt factors for the 1,3-D are:

Shallow inje ction w/ h i g h perm eability tarp or no tarp-broadcast 65%

Shallow inje ction w/ thre e water trea tm ents 44%

Deep injec t ion w/ high perm eability tarp or no tar p -broadc a st 26%

Drip w/ high perm eability tarp or no tarp 29%

C. Chloropicrin

The m a jority of chloropicrin is applied as a m i xture with either m e thyl brom ide or 1,3-D; a few

applications use chloropicrin as the sole fum i ga nt. The sam e a pplication m e thods that are used

for m e thyl brom ide or 1,3-D will be used for chlo ropicrin, b u t with different app lication m e thod

adjustm e nt factors.

1. Chloropic r in Emiss i o n Studies

Chloropicrin registrants m easured chloropicrin em issions from se veral field applications (Beard

et al. 1996). This study provides ad equate data to characterize chlo ropicrin em issions for m o st of

the current application practices . Em issions m easured in this study showed relative differences

sim ilar to methyl brom i d e, with low e r em issions associated with tarped broadcast applications

and higher em issions associated with untarped broadcast and bed appl ications (Table 4).

However, the study did not m easure em issions fo r deep injection application m e thods, so the

effect of injection depth is unknown. Data presente d by the chloropicrin re gistrants yield sim ilar

conclus i ons, except the two studies Gillis and S m ith (2002) and Lee et al. (1994) are either not o f

sufficient quality or do not include sufficient data to judge the quality to support their use in the

DPR estim at ion of the adjustm e nt factors. Chlo ropicrin registrants also m easured em i ssions

associated w ith chem igation of chloropicrin through a drip irrigati on system (Knutes on and

Dolder, 2000; Rotonardo, 2004; van W e senbeeck and Phillips, 2000). These studies provide

adequate data for the em issions from the drip application m e thod, and shows substantially lower

em issions than injection m e thods (Table 4). Gao and Trout (2007) used flux cham bers to

estim ate em issions for several chloropicrin and 1,3-D applic ation m e thods, including highdensity polyethylene tarpaulin, hi gh-density polyethylen e tarpaulin with pre-irrigation, single

post-app lic a tion wate r tr eatm e nt, m u ltip le pos t-a pplica tion w a ter tre a tm ents (in t e r m ittent

watering-in), and virtually im per m ea ble film . Th ose research ers repo rted problem s maintaining a

seal between the soil an d the cham ber. Conseq uently, predictions of chloropicrin em issions

associated w ith th e interm ittent watering-in application m e thod are subject to con s iderable

uncertainty because the Gao and Trout (2007) st u dy is the on ly inform ation available f o r

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 10

chlorop i cr in on this m itigation m easure. Howe ver, reductions observed in their resu lts are

qualitatively consistent with dem o nstra t ed r e du ctions in MI TC em issions f o r interm itten t

watering-in m e thods.

2. Chloropic r in Applica t ion Method Adjustment Factors

The Beard et al. (1996), Knutes on and Dolder (2000), Rotona rdo (2004), and van W e senbeeck

and Phillips (2000) stud ies will b e us ed to produce the DPR application m e thod adju stm e nt

factors. The em issions from Beard et al. (1996) are shown in Table 4. Sim ilar to the proposed

m e thyl brom ide factors (Barry, 2006), the prop osed chloro picrin f actors only distinguish

between tarpaulin and no tarpaulin. No depth f actor will be included. All broadcast tarpaulin

m e thod e m i ssion results will be com b ined to p r o duce an average estim a te.

The chloropicrin data set is sm all, as a result it is im possible to reliably distinguish between

em issions for bed and broadcast applications. Th us, no separate field adjustm e nt factor for

bed m e thods will be estim a ted. Instead, based on the known high-em ission characteristics of

m e thyl brom ide bed applications (Barry, 1999), th e chloropicrin em ission estim ates for bed will

be com b ined with the no tarpaulin m e thod.

The drip application m e thod is separated because the em issions appear to be substantially lower

than the shank injection m e thods.

As with m e t hyl brom ide, chloropicrin applications m e thods in 1990/91 used m o re perm eable

low-density polyethylene tarp aulins. Stangellhini (2006b, A ppendix 1) proposes, and DPR

agrees, that 1990/91 chloropicrin applications should be assigned th e application m e thod

adjustm e nt factor for applic ations without a tarpaulin.

DPR will assum e that re ductions in c h loropicrin em issions f o r interm itten t water i ng- in consisting

of three post-fum i gation water treatments is approxim ately one-third less than an untarped

application. Other application m e t hods that appear to reduce chlo ropicrin em issions, such as

pre-irrigation and virtually im pe r m eable film s m a y be problem atic due to labeling requirem ents

and other factors (Gao and Tr out, 2007). Therefore, these application m e thods are not

recomm ended at th is tim e.

Based on the em ission data shown in Table 4 and the assum p tions discussed above, the

application m e thod adjustm e nt f actors for chloropicrin are:

Shallow inje ction w/ h i g h perm eability tarp or no tarp-broadcast 64%

Shallow inje ction w/ low perm eability tarp-b road cast 44%

Shallow inje ction w/ h i g h perm eability tarp or no tarp-bed 64%

Shallow inje ction w/ 3 w a ter tre a tm ents 43%

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 11

Shallow inje ction w/ low perm eability tarp-b ed 64%

Deep injec t ion w/ high perm eability tarp or no tar p -broadc a st 64%

Deep injec t ion w/ low perm eability tarp-bro adca st 44%

Deep injection w/ 3 water treatm e nts 43%

Drip w/high perm eability tarp 12%

Drip w/low perm eability tarp 12%

C. Metam-sodium and Metam-potassium

Metam

- sodium and m e tam

- potassium fum i gant action and VOC e m issions are due to the

hydrolysis product MITC, which is generated when sufficient water is applied to either

m e ta m

- sodium or m e tam

- potassium. The two activ e ingredients display essentially identical

chem ical behavior. In the rem a i nder of this docum ent m e ta m be used to collectively refer to both

m e ta m

- sodium and m e tam

- potassium. EPs for produc ts containing these chem icals are expressed

on an MITC equivalent basis (Spurlock, 2002a, 2005) . Here em ission factor s are also derived on

an MITC em ission basis.

DPR proposes application m e thod ad justm e nt factors for eight m e ta m field application m e thods:

Using trac to r shanks to inject m e tam at shallow depths

Che m igation through sprinkler irrigation system s

Post-fum iga tion water treatm e nts for both sh ank injection and spri nkler applications

Spraying m e tam on the soil surface a nd incorporate us ing a ro totille r

Spraying m e tam on the soil surface and c over with additional soil (soil capping)

Che m igation through flood irrigation system s

Chem igatio n with drip irriga tion sys t em s

1. Metam-Sodium Emission Studies

The Metam

- sodium Task Force sub m itted results from field studies cond ucted under their

1997-2001 Field Program. The earliest studies monitored MITC air concentrations associated

with standard sprinkler and standard shank in jection applications (Merricks, 1999). Standard

sprinkler and standard shank in jection m e thods include water tr eatm ents imm e diately following

com p letion of the application. Field study resu lts were also s u bm itted for shank injection and

sprinkler ap plica tions e m ploying ne w post-f u m i ga tion water trea tm ents as m itigation m e asures

aim e d at suppressing MITC e m issions (Merri cks, 2001; Merricks, 2002) . The post-fum i gation

water trea tments cons ist of water app lied im m e di ately following the application but also

additional w a ter, usually at sunset of the firs t and second evenings following com p letion of an

application. Em ission profiles devel oped for all four of these applic ation m e thods have been used

previously by DPR to develop MITC buffer zones (Barry, 2006).

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 12

DPR recently received a study ch aracterizing a m odified interm ittent watering-in schedule

(Sulliv an et al., 2005). T h e m odification elim inates the watering-in on th e second nigh t and alters

the watering-in on the first night so that 2 rounds of half the sprinkl er lines were run at a rate of

0.2 inches/hour for 2 hours to ap ply a total of 0.4 inches over 4 hours. Thus, there are two

watering-in sessions instead of th ree. This study has received an initial review and several data

gaps were n o ted. At th is tim e, DPR has not com p letely rev i ewed and found the study acceptable.

However, this study included a 3-watering-in application done at the sam e ti m e for

com p arison,.That three-watering-i n application shows m a ss loss c onsistent with the Merricks

(2002) study results. Therefore, it is likely the stu dy will be fo und acceptable once the data gaps

are add r essed.

DPR has three m e ta m

- sodium drip method and on e rototiller m e thod e m i ssion profiles developed

using results from three field studies (Levin e et al, 2005; Li et al ., 2006; Wofford 2005).

Table 5 sho w s the total MITC em iss i ons ove r th e 96-hour flux profiles for each of th e

application m e thods. The total MIT C availa ble for em ission was calculated assum i ng a

m a xi m u m, i mmediate conversion of m e tam

- s odium to MITC of 95% ( W ales, 2000) and

adjusting for difference in m o lecular wei ght betw een m e ta m

- sodium and MITC.

2. Metam A pplica tion Method Adjustment Fa ctors

The m e tam

- sodium data set is sm all, as a resu lt it is im possible to re liab l y distingu ish between

em ission rates for sprinkler and shank injection m e thods. Howeve r, relative to the standard

application m e thods, the em issions are substantia lly lower for post-fum i gation water treatm ents

of both sprinkler and shank injec tion. Thus, sprinkler and shank injection m e thods are com b ined

but standard and post-fum i gation water treatm ents are sep a ra ted. The drip and roto tille r

application m e thods are separate d because the em issions observed in L e vine et al. (2005) and

Wofford (2005) are substantially lower than observed for other application m e thods.

Other application m e thods were commonly us ed in 1990/91 as well as currently, but the

em issions have not been m easured either in the laboratory or in th e field. S p ecifically, no

em ission data is availab l e for m e thods that c onsist of spraying m e tam on t h e soil su rface and

covering with additional soil (so il capping) or for m e thods that consist of chem igating using

flood irrigation system s. In order to account for the em issions from these application m e thods in

1990/91, DPR assum e s t h at em issions from the so il capping m e thod are the sam e as rototiller,

and em issions from flood chem igation are the sam e as sprinkler.

All of the metam studies and em issions described above were daylight applications. Unlike other

fum i gants, m e ta m applications commonly have hi gher em issions at night com p ared to the day,

particula r ly if applica tio ns occu r at night. W o ffor d et al. (1994) m easured em issions of nearly

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 13

100% from a night sprinkler applic ation. It is likely that other m e ta m application m e thods also

have higher em issions when done at night. Except for the standard sprinkler m e thod, the

em issions for m e ta m night applications are unknown. The frequency of night applications is also

unknown. Therefore, DPR does not currently acc ount for the em ission difference between day

and night applications.

Based on the em ission data shown in Table 5 and the assum p tions discussed above, the

application m e thod adjustm e nt factors for m e ta m (as a percentage of MIT C ) are:

Shallow inje ction w/ h i g h perm eabili ty tarp or no tarp-bed 77%

Shallow inje ction w/ 3 water trea tments 21%

Shallow inje ction w/ 2 w a ter tre a tm ents 28%

Rotovate/rototill 14%

Soil capping 14%

Sprinkler 77%

Sprinkler w/ 3 water treatm ents 21%

Sprinkler w/ 2 water treatm ents 28%

Flood 77%

Drip w/ high perm eability tarp or no tarp 9%

Drip w/ low perm eability tarp 9%

D. Da zomet

Sim ilar to metam

- sodium and m e tam

- potassium , dazom e t fum i gant action and VOC e m issions

are due to the hydrolysis product MITC, which is generated when sufficient water is applied to

dazom e t. In addition to their chem ical differenc es, dazom e t is for m ulated as granules while

m e ta m

- sodium and m e tam

- potassium are form ulated as liquids. The EP for dazom e t is expressed

on an MITC equivalent basis (Spurlock, 2002a , 2005). Here application m e thod adjustm e nt

factors are also derived on an MITC em ission basis.

DPR proposes application m e thod adjustm e nt f actors for two dazom e t application m e thods:

m e thods for which dazo m e t is applied to the so il surface follo wed by post-fum i gation

water treatments, and m e thods for which dazom e t is incorporated into the soil followed by

post-f u m i gation water tre a tm ents.

1. Dazomet Emission Studies

The data set for dazom e t consists of three stud ies, two surface applied and one incorporated

(Table 5 ) . The regis t rants for a dazo m e t product subm itted study results that included air

concentratio ns and em ission calculations for a surface and an incorporated application

(Certis, 200 4). There is significan t u n certainty in the em issio n estim ates for both th e s u rface

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 14

and the in co rporated app lication m e thods due to the very calm wind conditions du rin g the

studies. Out of 18 sam p ling periods f o r each s t ud y only three sam p ling periods from the

incorporated application and none of the sam p ling periods from th e surface application resulted

in statistically significant regres sions used to estim a te the emi ssion rate. A third study conducted

by DPR (Fan, in progres s) m onitored a surface ap plication to sm all plots o f dazom e t. The

regression analysis used to estim a te em issions was statistically significa nt, but resulted in an

em ission calculation that was a factor of ten highe r than the registrant s t ud ies. Becaus e of the

discrepancies in the em ission estim a tes between th e thre e stud ies, DPR and the reg i str a nt jo intly

initiated a fourth study. The analysis of the data from that study is in progress. Additionally, all

of the available stud ies m a y underestim ate VOC em issions from dazom e t because of other VOCs

for m ed by its degradation. The available studies only m easured MITC, but other degradation

products m a y also have significant VOC e m issions (Subramanian, et al. 1996).

2. Dazomet Application Method Adjustment Fa ctors

The available data s e t for dazom e t is sm all and th e em ission factors vary by a factor of ten, so an

average of the f r action o f MITC em itted f r om all of the studie s is used a s the inte rim applica tion

m e thod adjustm e nt factor for all applications of dazom e t products. DPR may revise this

adjustm e nt factor once the third and fourth st udies are com p leted. DPR may also revise this

adjustm e nt factor after further evaluation of th e other dazomet degradation products. The interim

application m e thod adjustm e nt factor for all dazom e t application m e thods is 17%.

E. Sodium Tetrathiocarbonate

Sodium tetrathiocarbonate fum i gant action a nd VOC e m issions are due to the hydrolysis

product carbon disulfide, which is generated wh en sufficient water is applied to sodium

tetrathiocarbonate. The E P for sodium tetrat hiocarbonate is expressed on a carbon disulfide

equivalent basis (Spurlock, 2002a, 2005). Here app lication m e thod adjustm e nt factors are also

derived here on a carbon disulfide em ission basis.

DPR proposes application m e thod adjustm e nt f actors for three sodium tetrathiocarbonate

application m e thods: chem igation using drip irrigation system s, che m iga tion using

m i ni-sprinkler system s, and flood/furrow chem igation.

1. Sodium Tetrathiocarbona te Emiss i on Studies

Evaluations by DPR staff conclude d that m i ni-sprinklers potentia lly result in higher off-site

carbon disulfide air concentrations relative to the other app lication m e thods (Haskell, 1995).

Thus, this m e thod m a y also represent worst-ca se em issions of carbon disulfide. DPR has one

direct flux (em i ssion) study charac terizing em issions of carbon disu lfide following application of

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 15

sodium tetrathiocarbonate by m i ni-sprinklers (P illing, 1996). This study was the basis for buffer

zones on the current labels. Em issions were ch aracterized by the integrated horizontal flux

m e thod ( W ilson and Shum, 1992) for 34.2 hours consis ting of: (1) the app lication, (2) follow-up

irrigation (w atering-in), and (3) an addition a l 24 hours after com p letion o f watering-in. The

em ission estim a tes indicate that 9.6% of the carbon disulfide gene rated by the sodium

tetrathiocarbonate product was em itted dur ing the 34.2 hours sam p led. The em ission profile

shows the peak em issions occurr ed during the application pro cess and then dropped rapidly

to low em issions that were relatively uniform in value between 0.41 m i crogram s per square

m e ter-second (ug/m 2 

# sec) and 1.02 ug/m 2 

# sec. However, on the morning of the second day

em issions began to rise. At 0900 hours on th e second day the em ission estim a te was

1.23 ug/m 2 

# s ec and the last 4-hour interval (m id-poi nt tim e 1700 hours) showed an em i ssion

estim ate of 2.6 ug/m 2 

# sec. The em ission profile f o r the second night is unknown. Based

upon em ission profiles for standard shank and st andard sprinkler app lication m e thods of

m e ta m

- sodium , it is possible that without wate ring-in on the second nigh t the em ission of

carbon disulfide would have continued to rise. Th us, the 9.6% estim ate of total carbon disulfide

em issions may underestim ate the true total em issions.

2. Sodium Tetrathiocarbonate Appl ication Me th od Adjustment Factors

We assum e that the em issions from drip a nd floo d/furrow chem igation are the sam e as

m i ni-sprinkler. Based on the 9.6% em ission rate m easured in the study described above, the

application m e thod adjustm e nt factors for sodium tetrathiocarbonate are:

Drip 10%

Sprinkler 10%

Flood 10%

F. Comments on the initial emissio n estima te s and other fumigant emissions considerations

DPR received num e rous comments on its in itial em ission estim a tes contained in the A p ril 6

m e morandum, but they had common them es. Several commentors disagreed with the studies that

DPR relied on to estim a te em issions. Som e sugge sted that D P R should use additional published

studies or studies unavailable to DPR to supplem ent the data used to estim a te e m issions. Som e

people com m e nted that DPR used several unrepres entative studies to estim ate em issions, or the

data a r e insu f f i cient to es tim ate em issions. DPR considered o t her stud ies p r ior to its in itia l

estim ates, and reconsid ered them after receiv i ng comments. In summary, the current set of

studies u s ed in this analy s is is the da tabase av ailable. DPR staff has included in this analysis

those stud ies that h a ve b een rev i ewed and accep ted as sufficient quality to provide reliable

results. The included studies were conducted at a variety of locations under a variety of

m e teorological cond itio ns and over the entire y e ar . The variety of locatio ns, application m e thods,

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 16

and m e teorological conditions are vari ed in large part due to the di verse nature of agriculture in

California. Appendix 4 contains a summ ary of t h e fum i gant em issi on studies that it did not use

and the reasons for excluding the data.

DPR is relying on several dozen field studies to d e term ine the em issions associa t ed with the

different ap plication m e thods, and u s ing surrogate field data where necessary. In som e cases

these field studies do not agree with laboratory st udies. For exam ple, m u l tiple field studies show

that depth of injection has no effect for m e thyl brom ide application s , at le ast with in th e depth

range studied (10-24 inches). Multiple field studi es also show that norm al tarpaulins have no

effect on 1,3-D em issions. Multiple f i eld studies show that bed fum i gations have higher

em issions than broadcast fum i gations for m e t hyl brom ide. DPR believe s that field s t u d ies

provide a m o re accu rate estim ate of em issions than laboratory studies. Because of the

discrepancies between laboratory an d field studies, DPR intends to continue to rely on field

studies to es tim ate em issions.

No flux chamber estim ates of em issions are used at th is tim e because there are s i gnificant

technical iss u es associated with flux cham ber estim a tes includ ing: (1 ) pote n tia lly s i gnif i cant

effects on th e local environm ental co nditions wh er e th e chambers are placed relativ e to the field

as a whole. This effect m a y be largest for stat ic cham bers but m a y also affect dynam i c cha m be rs,

(2) the sensitivity of dynam i c cha m ber results to pressure gradie nts created by the air flow, and

(3) the very lim ited coverage of the field by the sam p le cha m bers which can introduce a high

degree of heterogeneity in the flux results (R eichm a n and Rol s ton, 2002; Majewski et al., 1995;

Yates 2006).

DPR has m a de several revisions to the 1,3-D em i ssion estim ates based on the comm e n ts

received. In order to fully utilize the 4 st udies, D P R originally com b ined them by linear

interpolation to estim a te the flux at 2 standard depths: 18 inches and 12 inches. DPR requested

the peer reviewers to specifically evaluate th is m e thod for estim ating e m issions and other people

commented on these estim a tes. Both peer revi ew ers found the linear in terpolation approach

reasonable. However, other pe ople comm ented that DPR should group the studies by depth and

use the av erage of each group to es tim a te e m issions, consistent w ith th e approach DPR used for

the other fum i gants. DPR agrees with these co m m e nts and has grouped the studies into deep (18

inches or deeper) and shallow (14 and 12 inches) applications and sim p le averages taken of the

em ission percentage in each group. S e veral peopl e comm ente d that that the 3-water treatm ent

regim e for m e ta m may be an ineffective m e thod to reduce em issions from deep injections of 1,3­

D because the m onitoring data sho w s later em issi ons associated with th is applicatio n m e thod.

DPR agrees with the comment and has rem ove d this m e thod since the em issions cannot be

reliably e s tim a ted.

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 17

Several people comm ented that DPR should appl y other adjustm e nt factors to the fum i gant

em ission estim a tes. DPR considered other em ission adjustm e nts prio r to its initial es tim a tes, and

reconsid ered them after receiv i ng co mments. DPR believes there are insu fficient data to further

adjust em issions due to tarpaulin perm eability (e

. g., virtu a lly im per m eable film s), temperatu r e,

soil typ e , or other f acto r s

. W h ile it is like l y tha t other factors influence fum i gant e m issions, the

field-to-field variab ility is too high, and the data are insuffi cient to discern and quantif y the effect

of other factors. In add i tion, any adju stm e nts need to be enforceable by field inspectors.

Distinguishing soil type or other factors m a y be too difficult by observation or sim p le field tests.

Several people comm ented that DPR should suppl em ent its em ission estim ates with com puter

modeling, such as CHAIN_2D. DPR believes it is prem ature to use a first-principle model to

estim ate em issions. DPR m a y eventu ally us e this or other m odels to supplem e nt its emission

estim ates, but the current validation is insufficien t and several input variables are difficult if not

im possible to estim ate.

Som e people comm ente d that DPR should accou n t for r eactivity. In this cont ext, reactivity refers

to the ability of a speci fic chem ical to create ozone. Ca rter and Malkina (2007) studied the

reactivity of several pesticides and found that m e thyl brom ide and MITC have relatively low

reactivity, with m a xi m u m increm ental reactivi ties of 0.03 and 0.35, respectively. Chloropicrin

and 1,3-D have relatively high reactivity, with m a xim u m increm ental reactivities of 2.2 and 5.4,

respectively. The m a xi mum incr em e n tal reactivity is an estim ate of the amount of ozone

created, und er a specified set of conditions. Fo r exam ple, one pound of m e thyl brom ide will

create 0.03 pounds of ozone under the specified conditions. DPR agrees that Carter’s study

accurately estim ates the reactiv ity of the fum i gants. However, the fum i gants are VOCs under

federal law. See Title 40, Code Federal Regula tions, § 51.100(s). Unless the U.S. Environm ental

Protection A g ency am ends part 51.100, DPR must include these fum i gant em issions in the total

VOC e m ission inventory. DPR canno t exclude either m e thyl brom ide or MITC from the total

pesticide V O C inventory based on their reactivit y. DPR m a y, and would like to, consider the

reactivity of various pesticides when designing V O C control m easures, but m u st do so within the

bounds of its requirem e nt under federal law to ob tain the necessary m a ss-based (as opposed to

reactivity-based) reductions in VOC em issions. When the 1994 Pesticide Plan, that the court

order enforces, was included in SIP, neither the State nor U.S. Environmental P r otection Agency

appreciated that a significant fr action of the VOC em ission that the P l an would control do not

appreciably contribute to ozone. Unless SIP is am ended to account for this inform ation, DPR has

a lim ited ability to inc l ud e such inf o r m ation in its regula t ory d ecis i ons and still m u st meet its

legal obligation.

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 18

G. Othe r pe stic ides

Fum i gants are the dom inant contributors to pest icide VOCs, generally re sponsible for at least

50–60% of em ission in most California nonattai nm ent areas. The next largest class of

high-contributing pesticides is li quid for m ulations such as emulsi fiab le co ncentrates. In som e

cases, em issions calculated directly f r om the th ermogravim etric analyses m easure m ents without

accounting for application m e thod may over-estim ate actual field em issions for some of these

products. This m a y be especially true for products that are incorporated in to the soil. In other

cases, such as high solvent form ulations that are f o liar app lie d, it is un lik ely tha t f i eld processe s

reduce em issions significantly. In an y event, th er e is little, if any data av a ilab l e tha t would allow

estim ation of application m e thod adjustm e nt fact ors for non-fum i gant pesticides. Consequently,

application m e thod adjustm e nt factors for non-fum i gants are assum e d to be 100% in all years.

DPR m a y re consider these non-fum i gant field ad justm e nt factors as further data becom e s

available.

IV. Estimated Frequency of Use fo r Each Fumigant Application Method During

May–Octob er (Method Use Fractions)

In California, all agricultural and commercial pesticide applica tions m u st be reported. County

agricu ltu ral comm issioners and DPR com p ile thes e PURs into a database. The PUR database

includes the identity of the pr oduct applied, the amount applied, lo cation, date, cr op/site treated,

and other inform ation. DPR uses the pounds of pr oduct applied recorded in PUR database to

calcu late the VOC em issions f o r eac h pesticid e a pplica tion in cluded in th e pesticide VOC

em ission inventory. PUR database contains general inform ati on about the application m e thod

(i.e. air, ground, or other), but it does not indicate the specific application m e thod. Therefore,

another adju stm e nt is needed to acco unt for the u s e of each fum i gant application m e thod. DPR

regulation 07-002 contains provisi ons to include m e thod of a pplic ation for field fum i gations in

PURs, so the procedu r e outlin ed her e will no t be used in th e f u ture.

In general, different crops us e different fum i gant applicati on m e thods. Roush (2006) found that

the different nonattainment areas ha ve different crops responsible for the m a jority of pesticide

VOC e m issions. Therefore, each non attainm e nt ar ea should h a ve a different set of adjustm e nt

factors to characterize the use of fumigant application m e thods. W h ile the application m e thod

depends on the crop to be planted, other factors such as soil type, cost, and equipm ent

availability also influence the choice of app lication m e thod. For exam ple, strawberries always

use a shallow applicatio n m e thod. However, the tarp broadcas t and tarp bed application m e thods

are both commonly used for stra wberries, and these applica tion m e thods have different

em issions. Therefore, the type of crop is an unreliable surrogate to identify the fum i gant

application m e thod in som e cases.

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 19

DPR proposes to use a v a riety of m e t hods to estim ate the use of each of the fum i gant application

m e thods ( m ethod use fraction ) . The m e thod for 1,3-D is the most accurate. As required under

DPR’s 1,3-D m a nage ment plan, th e registrants m a intain record s of the specific application

m e thod for a ll 1,3-D applications. Johnson ( 2006) describes the May–October m e thod use

fractions, based on the registrants’ data.

Lawson (2006) provides a survey of m e ta m

- sodi um practices by several dozen growers and

applicators in certain areas of the state. This surv ey includ es a com p ila tion of the application

m e thods. The survey includes specific inform ation for three nonattainm e nt areas, as w e ll as the

top ten counties. DPR uses the percentage break down described in Lawson (2006) on the use of

the various m e ta m

- sodium applications for the San Joaquin Valley, Southeast Desert, and

Ventura nonattainm e nt areas. DPR uses the br eakdown for the top ten counties described in

Lawson (2006) as a surrogate for the Sacram ento Metro nonattainm e nt area, and Ventura as a

surrogate for the South Coast nonattainm e nt area.

Sim ilar to the approach described by Sta ngellhini (2006a, 2006b; Appendix 1), DPR

uses information from the PURs to estim at e the May–October m e thod use fractions for

m e thyl brom ide and chloropicrin based on the f o llowing assum p tions:

• For 1990/91 m e thyl brom ide and chloropicrin a pplications, one-half of all strawberry, row,

vegetable, and nursery crops were fum i gate d using a shallow injection broadcast m e thod

with a high perm eability tarpau lin o r no tarp au lin , and one-ha l f were cond ucted with a

shallow injection bed m e thod a nd a high perm eability tarpaulin.

• For 1990/91 m e thyl brom ide and chloropicrin applications, all tree and vine crops w e re

fum i gated using a deep injection m e thod with a high perm eability tarpaulin or no tarpaulin.

• For 2004 m e thyl brom ide applications, all ro w, vegetable, and nursery crops (except

strawberries) were fum i gate d using a shallow injection broadcast m e thod with a low

perm eability tarpau lin.

• For 2004 m e thyl brom ide applications, one-hal f of the straw b erry applications were

conducted w ith a sh allow injection b r oadcast m e thod and a lo w perm eability tarpau lin, and

one-half of the strawberry applications were conducted with a shallow injection bed m e thod

and a low pe rm eability ta rpaulin.

• For 2004 m e thyl brom ide applications, all tree and vine crops were fum i gated using a deep

injection m e thod with a lo w perm eability tarpaulin.

• For 2004 chloropicrin applications , all row, vegetable, and nursery crops (except straw b erries

and Inline ® 

# applications) were fum i gated using a sh allow injection broadcast m e thod with a

low perm eability ta rpau lin. In line ® 

# applications were conducte d with a drip chem igation

m e thod.

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 20

• For 2004 chloropicrin applicati ons, strawberry Inline product applications were conducted

with a drip chem igation m e thod. For the rem a in ing strawberry applications, one-half were

conducted w ith a sh allow injection b r oadcast m e thod and a lo w perm eability tarpau lin, and

one-half were conducted with a shallo w in jection bed m e thod and a low perm eability

tarpau lin.

• For 2004 chloropicrin applicati ons, all tree and vine crops were fum i gated using a deep

injection m e thod with a lo w perm eability tarpaulin.

NOTE: 2004 is the m o st recen t year for whic h DPR has calculated a VOC em ission inventory.

The m e thod use fractions for dazom e t have no eff ect on the total em ission estim ates because the

application m e thod adjustm e nt factor is 17% fo r both application m e thods. Sim ilarly, the m e thod

use fractions for sodium tetrat hiocarbonate have no effect on the total em ission estim a tes

because the application m e thod adjustm e nt factor for all three applicat io n m e thods is 10%.

The inform a tion from the 1,3-D registrants, Laws on (2006), and PURs is adequate for estim a ting

the m e thod use fractions during the 1990/91 base year and currently. Tables 6–10 show the

m e thod use fractions during the 1990/91 base y ear in each nonattainm e nt area. Tables 11–15

show the m e thod use fractions for 20 04 in each n onattainm e nt area. Tables 16–20 show the

predicted method use fraction s if all applicatio n s switched to a “low-em i ssion” m e thod for each

nonattainm e nt area. This last set of method use fractions was predicted by assum i ng that all

“high-em ission” m e thods switch to the m o st si m ilar “low-em i ssion” m e thod. For example,

Table 11 shows that 33% of th e chloropicrin applications w e re conducted using shallow

injection, tarped, bed (high-em ission) m e thod in the Sacram e n to Metro area during 2004. As

shown in Table 16, DPR predicts that applicat ors using this m e thod change to the shallow

injection, tarped, broadcast m e thod (low -em i ssion) m e thod to reduce em issions.

The m e thyl brom ide and chloropicrin regist ran t s commented that the April 6 m e m o randum

contained errors in som e of the m e thod use fractions. Based on these com m e nts and follow-up

inform ation (W ilhelm

, 2007), DPR has revised its m e thyl brom ide and chloropicrin m e thod use

fractions for the 1990/91 base years for row, vegetables, and nursery crops. These changes

slightly increase the base year due to the m o re frequent use of higher emission m e thods. Other

suggested changes to the m e thod use fractions were not incorporated due to the extensive

recalculatio ns the chang e s would req u ire, a nd the changes involve revisions to the 2004

em issions, which have m i ni m a l regulatory im pact.

Several comm entors objected to the use of th e undocum ented m e thod use fractions for m e ta m

. DPR does not norm a lly use undocum ented data. However, in this case the registrants’

inform ation and professional judgm ent are likel y more reliable than DPR’s, and DPR has

em ployed the suggested m e thod use fractions. At DP R’s request, the registrants have agreed to

provide docum entation on the m e thod use fractions.

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 21

V. Estimate d Effect of Fumigant Application Method Adjustmen t s o n the Volatile Organ ic

Compound Inventory

Previously, DPR did not include application m e thod adjustm e nt f actors and m e thod use fractions

as part of its pesticide V O C e m ission calculati o n s. Histor ica lly, DPR assum e d all ap plica tion

m e thod adjustm e nt factors were 100%, and that fum i gant use is equiva lent to fum i gant VOC

em ission. Table 21 summ arizes the May–October em ission inventory (ass um ing 100% fum i gant

VOC e m issions) for 1990, 1991, and 2004 in each nonattainm e nt area, and shows an overall

increase in f u m i gant use and em issions for m o st nonattainm e nt areas.

This m e m o r a ndum derives various fum i gant- and application m e thod-specific adjustment factors

to refine the accuracy of the VOC inventor y. Tab l e 22 summ a r izes the app lication m e thod

adjustm e nt factors associated with each fu m i gant and application m e thod com b ination, and

shows that most current application m e thods have lower em issions than m e thods used in

1990/91.

Tables 6–20 summarize the May–October m e t hod use fractions during 1990/91, 2004, and the

predicted method use fractions if all applicatio ns switched to a “low-em i ssion” m e thod for the

2008 regulations. The predicted m e thod use frac tions under the proposed regulations were

determ ined using DPR’s best professional judgm ent and the application m e thods used during

2004.

Estim ated pesticide VOC e m issions for May–Oct ober that account for fum i gant application

m e thods are calcu lated b y m u ltiply in g the unadju s ted VOC em issions shown in Table 21, by the

application m e thod adjustm e nt factors show n in Table 22 and the corresponding m e thod use

fractions in Tables 6–20. Table 23 shows the results of these cal culations and provides estim ates

of the adjusted VOC e m i ssions during the 1990/91 base year and 2004. Table 23 indicates that

application m e thod changes between 1990/91 and 2004 are insufficient to achieve the required

VOC reductions in the S a n Joaquin Valley, Sout heast Desert, and Ventura nonattainm ent areas.

While application m e thod changes since 1990/91 have lowered em ission rates, increased

fum i gant use m o re than offsets the application m e thod reductions.

Table 23 als o includes an estim ate o f the lowest pesticide V O C em issions curren tly f easible

through changes in fum i gant application m e thods . This was estim ated by assum i ng that all

field fum i gations in 2004 used “low-em i ssion” methods. Table 23 shows that even if all

fum i gant applications u s ed “low-em i ssion” m e thods, the VOC reduction s will be insu fficient

to m eet SIP obligations f o r Ventura and po ssibly insufficient for San Joaquin Valley and

Southeast D e sert. If future fum i gant use decr eases relative to 2004, the San Joaquin Valley and

Southeast D e sert non atta inm e nt areas will li kely a c hieve the re quired VOC reductions by

switching to “low-em i ssion” m e thods. Conversely, if future fum i gant use increases, these two

areas are un likely to achieve the requ ired VOC reductions by relying solely on changing to

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 22

“low-em i ssion” m e thods. The Ventura nonattain m ent area will likely re q u ire a sub s tantial

decrease in use during May–Octob er in order to achieve the re quired V O C reduction, even if all

applications changed to “low-em i ssion” m e thods.

Lim its on fum i gant e m issions during May–Oct ober within each nonattainm ent area could

achieve the required VOC reductions. Table 24 s hows the m a xim u m fum i gant em issions that

would achieve the required reductions, assum i ng VOC e m issions from nonfum igant pesticides

rem a in the sam e as 2004. If there are also no changes to the 2004 fum i gation practices (i.e. no

low-em ission m e thods are adopted), acres fum i gated and/or applica tion rates during the

May–October period would need to decrease approxim a tely 20–50% in the San Joaquin Valley,

Southeast D e sert, and Ventura nonattainm e nt areas in order to achieve the required V O C

reductions (Table 24). T h e Sacram ento Metro and South Coast nonattainm e nt areas easily

achieve the required reductions wi th c u rrent p r ac tices. It is lik ely that som e com b ination of

application m e thod changes and emission lim its is necessary to achieve th e required V O C

reductions for several nonattainm e nt areas.

cc: Paul H. Gosselin, D P R Chief De puty Director

Polly Frenkel, DPR Chief Counsel

Tobi L Jones, Ph.D., DPR Assistant Directo r

Jerom e R. Cam pbell, DPR Assistant Directo r

Sue Edm i ston, DPR Bra n ch Chief

Linda Irokawa-Otani, DPR Staff Services Manager I

# John S. Sanders, Ph.D.

Septem ber 29, 2007

Page 23

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Yates, S.R. Measuring herbicide volatilizations f r om bare soil. 2006. Environm ental Science and

Technology. 40:3223-3228.John S. Sanders, Ph.D.September 29, 2007Page 28Table 1. Summary of methyl bromide emission estimates fromDPR and registrantfield studies. The methylbromide application methodadjustment factors are twice the average emission values shown, based on the assumption that the peak 24-hour emissions are one-half thetotal emissions.Study ID1Bed/BroadcastTarpaulinTypeChiselTypeInjectionDepth(inches)DateAppliedPeakEmissionsin 24hrs (%)AverageEmissions (%)CV(%)SE1.1BedNoneRearwardcurved128/19/92343747SE1.2BedNoneRearwardcurved129/24/9256SE1.3/EH127-2BedNoneRearwardcurved1210/27/9240SE2.2BroadcastNoneForwardcurved2010/21/9262EH164-7BroadcastNoneForwardcurved201/22/9832S104.2-1BroadcastNoneForwardcurved243/8/9344S100B1.1BroadcastNoneForwardcurved243/13/9322S110.1BroadcastNoneForwardcurved2410/31/958.4TC199BroadcastHighbarrierNobelPlow126/30/92262452EH127-1BroadcastHighbarrierNobelPlow1210/26/9216EH150-6BroadcastHighbarrierNobelPlow122/13/979.8EH163-2BroadcastHighbarrierNobelPlow128/21/9740EH164-5BroadcastHighbarrierNobelPlow1211/1/9736EH164-10ABroadcastHighbarrierNobelPlow126/5/9836EH164-10CBroadcastHighbarrierNobelPlow126/5/9830EH164-10EBroadcastHighbarrierNobelPlow126/7/9817EH164-10GBroadcastHighbarrierNobelPlow126/7/9817TC324.1BroadcastHighbarrierNobelPlow127/25/986.8EH163-4BroadcastHighbarrierNobelPlow129/2/9826BR787.1ABroadcastHighbarrierNobelPlow126/24/9920BR787.2ABroadcastHighbarrierNobelPlow126/30/9948S110F1BedHighbarrierRearwardcurved67/13/936.28138EH164-2BedHighbarrierRearwardcurved69/8/9768EH164-11BedHighbarrierRearwardcurved610/6/98100BR787.1BBedHighbarrierRearwardcurved66/24/99100BR787.1CBedHighbarrierForwardcurved66/24/99100BR787.2BBedHighbarrierForwardcurved66/30/9976BR787.2CBedHighbarrierRearwardcurved66/30/9976EH150-2BedHighbarrierRearwardcurved612/12/96100EH164-6BedHighbarrierRearwardcurved612/17/971001Study IDs beginning with EH are DPR studies, all others areregistrant studies.John S. Sanders, Ph.D.September 29, 2007Page 29Table 2. Summary of methyl bromide emission estimates fromthe literature.Broadcast TarpReferenceStudy TypeSoil TypeDepth (cm)Emissions (%)Average(%)CV (%)JEQ Vol 24:742FieldSilty Clay Loam25324035JEQ Vol 25:185FieldSandy Loam2563JEQ Vol 26:310ColumnSandy Loam3043JEQ Vol 26:310ColumnSandy Loam3037JEQ Vol 26:310ColumnSandy Loam6026Broadcast NontarpReferenceStudyTypeDepth(cm)Emissions(%)Average(%)CV (%)JEQ Vol 24:742FieldSilty Clay Loam25896634JEQ Vol 26:310ColumnSandy Loam2082JEQ Vol 26:310ColumnSandy Loam3071JEQ Vol 26:310ColumnSandy Loam6038ES&T Vol30:1629ColumnSandyLoam3077ES&T Vol30:1629ColumnLoamySand3077ES&T Vol30:1629ColumnClay3037John S. Sanders, Ph.D.September 29, 2007Page 30Table 3. Summary of 1,3-D emission estimates.ReferenceApplicationMethodLocationMeasuredEmissions(%)AverageEmissions (%)(interpolatedto 18 inches)Gillis andDowling(1998)ShankBroadcast -14" depthSalinas, CA65651Gillis andDowling(1998)Shank Bed -12" depthSalinas, CA65Knuteson etal. (1995)ShankBroadcast -20-22" depthFirebaugh,CA26262Knuteson etal. (1992)ShankBroadcast -18" depthSalinas, CA25Knuteson etal. (1999)DripSalinas,CA2929Wesenbeeck& Phillipps(2000)DripDouglas,GA291Shallow application 12 inches2Deep application 18 inchesJohn S. Sanders, Ph.D.September 29, 2007Page 31Table 4. Summary of chloropicrin emission estimates.ReferenceApplicationMethodLocationEmissions (%)Average (%)CV (%)Beard (1996)Broadcast/No TarpArizona62.564.26.0Beard (1996)Broadcast/No TarpArizona61.4Beard (1996)Bed/TarpArizona68.644.235.6Beard (1996)Broadcast/TarpArizona62.3Beard (1996)Broadcast/TarpWashington33.8Beard (1996)Broadcast/TarpFlorida36.5Rotonardo (2004)Drip/low perm. tarp1511.827.2Knuteson and Dolder (2000)Drip/low perm. tarpCalifornia8.6van Wesenbeeck and Phillips(2000)Drip/high perm.tarpGeorgia12.312.3-John S. Sanders, Ph.D.September 29, 2007Page 32Table 5. Summary of MITC emission estimates. Allcalculations are on a 1-acre basis. See text for description of the applicationmethods.Metam-Sodium StudiesReferenceApplicationMethodMITCEmissions(lbs)Total MITC(lbs)Emissions(%)AverageEmissions(%)Merricks (1999)Standard Sprinkler1391728178Merricks (1999)Standard Shank638673Sullivan et al. (2005)Sprinklerw/2 Water Treatments311102828Merricks (2001)Sprinkler w/ 3 Water Treatments391722321Merricks (2001)Shank w/ 3 Water Treatments168619Levine, et al. (2005)Nontarp drip0.92214.49.1Levine, et al. (2005)Nontarp/intermittent drip0.6426.22.4Li, et al. (2006)Tarp drip3.581620.5Wofford (2005)Rototill1414Dazomet StudiesReferenceApplicationMethodMITCEmissions(lbs)Total MITC(lbs)Emissions(%)AverageEmissions(%)Certis (2004)Surface6.261374.5717Fan, in progressSurface4510542.9Certis (2004)Surface incorporated6.042692.3John S. Sanders, Ph.D.September 29, 2007Page 33Table 6. 1990/91 frequency of fumigation methods used (method use fractions) in the Sacramento Metro nonattainment area.Fumigation Method1%of AmountApplied1,3-D1ChloropicrinMethylBromideMetam3Dazomet3NaTetrathiocarbonate4Shallow injection w/highpermeability tarpornotarp-broadcast4237Shallow injection w/ low permeability tarp-broadcastShallow injection w/highpermeability tarpornotarp-bed423618Shallow injection w/ low permeability tarp-bedShallow injection w/2water treatmentsShallow injection w/3water treatmentsDeep injectionw/ highpermeability tarpornotarp-broadcast1614Deep injectionw/ lowpermeability tarp-broadcastRotovate/rototill/soil capping2100Sprinkler5533Sprinkler w/2watertreatmentsSprinklerw/ 3water treatmentsFlood1033Dripw/highpermeabilitytarpornotarp1034Dripw/lowpermeability tarp5Nonfieldsoil (structural/post-harvest)131Fumigation methods are described in detail in the text.2Negligible amounts of 1,3-D were applied during 1990/91.3DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.4DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 34Table 7. 1990/91 frequency of fumigation methods used (method use fractions) in the San Joaquin Valley nonattainment area.Fumigation Method1%of AmountApplied1,3-D1ChloropicrinMethylBromideMetam3Dazomet3NaTetrathiocarbonate4Shallow injection w/highpermeability tarpornotarp-broadcast2929Shallow injection w/ low permeabilitytarp-broadcastShallow injection w/highpermeability tarpornotarp-bed292933Shallow injection w/ low permeability tarp-bedShallow injection w/2water treatmentsShallow injection w/3water treatmentsDeep injectionw/ highpermeability tarpornotarp-broadcast4242Deep injectionw/ lowpermeability tarp-broadcastRotovate/rototill/soil capping3100Sprinkler6033Sprinkler w/2watertreatmentsSprinklerw/ 3water treatmentsFlood33Dripw/highpermeabilitytarpornotarp234Dripw/lowpermeability tarp2Nonfieldsoil (structural/post-harvest)1Fumigation methods are described in detail in the text.2Negligible amounts of 1,3-D were applied during 1990/91.3DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.4DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 35Table 8. 1990/91 frequency of fumigation methods used (method usefractions) in the SoutheastDesert nonattainment area.Fumigation Method1%of AmountApplied1,3-D1ChloropicrinMethylBromideMetam3Dazomet3NaTetrathiocarbonate4Shallow injection w/highpermeability tarpornotarp-broadcast5035Shallow injection w/ low permeabilitytarp-broadcastShallow injection w/highpermeability tarpornotarp-bed503410Shallow injection w/ low permeability tarp-bedShallow injection w/2water treatmentsShallow injection w/3water treatmentsDeep injectionw/ highpermeability tarpornotarp-broadcastDeep injectionw/ lowpermeability tarp-broadcastRotovate/rototill/soil capping100Sprinkler3033Sprinkler w/2watertreatmentsSprinklerw/ 3water treatmentsFlood5033Dripw/highpermeabilitytarpornotarp534Dripw/lowpermeability tarp5Nonfieldsoil (structural/post-harvest)311Fumigation methods are described in detail in the text.2Negligible amounts of 1,3-D were applied during 1990/91.3DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.4DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 36Table 9. 1990/91 frequency of fumigation methods used (methoduse fractions) in the Ventura nonattainment area.Fumigation Method1%of AmountApplied1,3-D1ChloropicrinMethylBromideMetam3Dazomet3NaTetrathiocarbonate4Shallow injection w/highpermeability tarpornotarp-broadcast5049Shallow injection w/ low permeability tarp-broadcastShallow injection w/highpermeability tarpornotarp-bed504920Shallow injection w/ low permeability tarp-bedShallow injection w/2water treatmentsShallow injection w/3water treatmentsDeep injectionw/ highpermeability tarpornotarp-broadcastDeep injectionw/ lowpermeability tarp-broadcastRotovate/rototill/soil capping100Sprinkler5033Sprinkler w/2watertreatmentsSprinklerw/ 3water treatmentsFlood33Dripw/highpermeabilitytarpornotarp1534Dripw/lowpermeability tarp15Nonfieldsoil (structural/post-harvest)31Fumigation methods are described in detail in the text.2Negligible amounts of 1,3-D were applied during 1990/91.3DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.4DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 37Table 10. 1990/91 frequency of fumigation methods used (method use fractions) inthe South Coast nonattainment area.Fumigation Method1%of AmountApplied1,3-D1ChloropicrinMethylBromideMetam3Dazomet3NaTetrathiocarbonate4Shallow injection w/highpermeability tarpornotarp-broadcast503Shallow injection w/ low permeability tarp-broadcastShallow injection w/highpermeability tarpornotarp-bed50320Shallow injection w/ low permeability tarp-bedShallow injection w/2water treatmentsShallow injection w/3water treatmentsDeep injectionw/ highpermeability tarpornotarp-broadcastDeep injectionw/ lowpermeability tarp-broadcastRotovate/rototill/soil capping100Sprinkler5033Sprinker w/ 2 watertreatmentsSprinklerw/ 3water treatmentsFlood33Dripw/highpermeabilitytarpornotarp1534Dripw/lowpermeability tarp15Nonfieldsoil (structural/post-harvest)951Fumigation methods are described in detail in the text.2Negligible amounts of 1,3-D were applied during 1990/91.3DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.4DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 38Table 11. 2004 frequency of fumigation methods used (method use fractions) in the Sacramento Metro nonattainment area.Fumigation Method1%of AmountApplied1,3-DChloropicrinMethylBromideMetam2Dazomet2NaTetrathiocarbonate3Shallow injection w/highpermeability tarpornotarp-broadcastShallow injection w/ low permeability tarp-broadcast5611Shallow injection w/highpermeability tarpornotarp-bed21Shallow injection w/ low permeability tarp-bed336Shallow injection w/2water treatmentsShallow injection w/3water treatmentsDeep injectionw/ highpermeability tarpornotarp-broadcast100Deep injectionw/ lowpermeability tarp-broadcast11Rotovate/rototill/soil capping15100Sprinkler533Sprinkler w/2watertreatments30Sprinklerw/ 3water treatmentsFlood1033Dripw/highpermeabilitytarpornotarp934Dripw/lowpermeability tarp1110Nonfieldsoil (structural/post-harvest)711Fumigation methods are described in detail in the text.2DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.3DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 39Table 12. 2004 frequency of fumigation methods used (method use fractions) in the San Joaquin Valley nonattainment area.Fumigation Method1%of AmountApplied1,3-DChloropicrinMethylBromideMetam2Dazomet2NaTetrathiocarbonate3Shallow injection w/highpermeability tarpornotarp-broadcast2Shallow injection w/ low permeability tarp-broadcast9679Shallow injection w/highpermeability tarpornotarp-bed16Shallow injection w/ low permeability tarp-bed21Shallow injection w/2water treatments5Shallow injection w/3water treatmentsDeep injectionw/ highpermeability tarpornotarp-broadcast98Deep injectionw/ lowpermeability tarp-broadcast116Rotovate/rototill/soil capping20100Sprinkler533Sprinkler w/2watertreatments25Sprinklerw/ 3water treatmentsFlood533Dripw/highpermeabilitytarpornotarp1434Dripw/lowpermeability tarp10Nonfieldsoil (structural/post-harvest)141Fumigation methods are described in detail in the text.2DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.3DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 40Table 13. 2004 frequency of fumigation methods used (method use fractions) in the SoutheastDesert nonattainment area.Fumigation Method1%of AmountApplied1,3-DChloropicrinMethylBromideMetam2Dazomet2NaTetrathiocarbonate3Shallow injection w/highpermeability tarpornotarp-broadcast4Shallow injection w/ low permeabilitytarp-broadcast6977Shallow injection w/highpermeability tarpornotarp-bed6Shallow injection w/ low permeability tarp-bed1919Shallow injection w/2water treatmentsShallow injection w/3water treatmentsDeep injectionw/ highpermeability tarpornotarp-broadcastDeep injectionw/ lowpermeability tarp-broadcast1Rotovate/rototill/soil capping100Sprinkler533Sprinkler w/2watertreatments10Sprinklerw/ 3water treatmentsFlood6033Dripw/highpermeabilitytarpornotarp96734Dripw/lowpermeability tarp1012Nonfieldsoil (structural/post-harvest)231Fumigation methods are described in detail in the text.2DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.3DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 41Table 14. 2004 frequency of fumigation methods used (method use fractions) in the Ventura nonattainment area.Fumigation Method1%of AmountApplied1,3-DChloropicrinMethylBromideMetam2Dazomet2NaTetrathiocarbonate3Shallow injection w/highpermeability tarpornotarp-broadcast2Shallow injection w/ low permeability tarp-broadcast4863Shallow injection w/highpermeability tarpornotarp-bed10Shallow injection w/ low permeability tarp-bed2837Shallow injection w/2water treatments15Shallow injection w/3water treatmentsDeep injectionw/ highpermeability tarpornotarp-broadcast4Deep injectionw/ lowpermeability tarp-broadcastRotovate/rototill/soil capping100Sprinkler33Sprinkler w/2watertreatmentsSprinklerw/ 3water treatments20Flood33Dripw/highpermeabilitytarpornotarp94534Dripw/lowpermeability tarp2450Nonfieldsoil (structural/post-harvest)1Fumigation methods are described in detail in the text.2DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.3DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 42Table 15. 2004 frequency of fumigation methods used (method usefractions) in the South Coast nonattainment area.Fumigation Method1%of AmountApplied1,3-DChloropicrinMethylBromideMetam2Dazomet2NaTetrathiocarbonate3Shallow injection w/highpermeability tarpornotarpbroadcastShallow injection w/ low permeability tarp-broadcast4061Shallow injection w/highpermeability tarpornotarp-bed10Shallow injection w/ low permeability tarp-bed3631Shallow injection w/2water treatments15Shallow injection w/3water treatmentsDeep injectionw/ highpermeability tarpornotarpbroadcastDeep injectionw/ lowpermeability tarp-broadcastRotovate/rototill/soil capping100Sprinkler2033Sprinkler w/2watertreatmentsSprinklerw/ 3water treatmentsFlood33Dripw/highpermeabilitytarpornotarp100534Dripw/lowpermeability tarp2450Nonfieldsoil (structural/post-harvest)81Fumigation methods are described in detail in the text.2DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.3DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 43Table 16. Predicted fumigation methods if only “low-emission” methods used (predicted method use fractions) in the SacramentoMetro nonattainment area.Fumigation Method1%of AmountApplied1,3-DChloropicrinMethylBromideMetam2Dazomet2NaTetrathiocarbonate3Shallow injection w/highpermeability tarpornotarp-broadcastShallow injection w/ low permeabilitytarp-broadcast8914Shallow injection w/highpermeability tarpornotarp-bedShallow injection w/ low permeability tarp-bedShallow injection w/2water treatments18Shallow injection w/3water treatments18Deep injectionw/ highpermeability tarpornotarp-broadcast100Deep injectionw/ lowpermeability tarp-broadcast1112Rotovate/rototill/soil capping100Sprinkler33Sprinkler w/2watertreatments23Sprinklerw/ 3water treatments22Flood33Dripw/highpermeabilitytarpornotarp934Dripw/lowpermeability tarp10Nonfieldsoil (structural/post-harvest)741Fumigation methods are described in detail in the text.2DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.3DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 44Table 17. Predicted fumigation methods if only “low-emission” methods used (predicted method use fractions) in the San JoaquinValley nonattainment area.Fumigation Method1%of AmountApplied1,3-DChloropicrinMethylBromideMetam2Dazomet2NaTetrathiocarbonate3Shallow injection w/highpermeability tarpornotarp-broadcastShallow injection w/ low permeability tarp-broadcast9880Shallow injection w/highpermeability tarpornotarp-bedShallow injection w/ low permeability tarp-bedShallow injection w/2water treatments11Shallow injection w/3water treatments210Deep injectionw/ highpermeability tarpornotarp-broadcast98Deep injectionw/ lowpermeability tarp-broadcast16Rotovate/rototill/soil capping20100Sprinkler33Sprinker w/2 watertreatments18Sprinklerw/ 3water treatments17Flood33Dripw/highpermeabilitytarpornotarp1434Dripw/lowpermeability tarp210Nonfieldsoil (structural/post-harvest)41Fumigation methods are described in detail in the text.2DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.3DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 45Table 18. Predicted fumigation methods if only “low-emission” methods used (predicted methoduse fractions) in the Southeast Desertnonattainment area.Fumigation Method1%of AmountApplied1,3-DChloropicrinMethylBromideMetam2Dazomet2NaTetrathiocarbonateShallow injection w/highpermeability tarpornotarp-broadcastShallow injection w/ low permeability tarp-broadcast89100Shallow injection w/highpermeability tarpornotarp-bedShallow injection w/ low permeability tarp-bedShallow injection w/2water treatments3Shallow injection w/3water treatments43Deep injectionw/ highpermeability tarpornotarp-broadcastDeep injectionw/ lowpermeability tarp-broadcastRotovate/rototill/soil capping100Sprinkler33Sprinkler w/2watertreatments38Sprinklerw/ 3water treatments37Flood33Dripw/highpermeabilitytarpornotarp96734Dripw/lowpermeability tarp1112Nonfieldsoil (structural/post-harvest)1Fumigation methods are described in detail in the text.2DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.3DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 46Table 19. Predicted fumigation methods if only“low-emission” methods used (predictedmethod use fractions) in the Venturanonattainment area.Fumigation Method1%of AmountApplied1,3-DChloropicrinMethylBromideMetam2Dazomet2NaTetrathiocarbonate3Shallow injection w/highpermeability tarpornotarpbroadcastShallow injection w/ low permeability tarp-broadcast76100Shallow injection w/highpermeability tarpornotarp-bedShallow injection w/ low permeability tarp-bedShallow injection w/2water treatments13Shallow injection w/3water treatments212Deep injectionw/ highpermeability tarpornotarpbroadcast4Deep injectionw/ lowpermeability tarp-broadcastRotovate/rototill/soil capping100Sprinkler33Sprinkler w/2watertreatments10Sprinklerw/ 3water treatments10Flood33Dripw/highpermeabilitytarpornotarp94534Dripw/lowpermeability tarp2450Non-fieldsoil(structural/post-harvest)1Fumigation methods are described in detail in the text.2DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.3DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 47Table 20. Predicted fumigation methods if only “low-emission” methods used (predicted method use fractions) in the South Coastnonattainment area.Fumigation Method1%of AmountApplied1,3-DChloropicrinMethylBromideMetam2Dazomet2NaTetrathiocarbonate3Shallow injection w/highpermeability tarpornotarpbroadcastShallow injection w/ low permeability tarp-broadcast7694Shallow injection w/highpermeability tarpornotarp-bedShallow injection w/ low permeability tarp-bedShallow injection w/2water treatments13Shallow injection w/3water treatments12Deep injectionw/ highpermeability tarpornotarpbroadcastDeep injectionw/ lowpermeability tarp-broadcastRotovate/rototill/soil capping100Sprinkler33Sprinkler w/2watertreatments10Sprinklerw/ 3water treatments10Flood33Dripw/highpermeabilitytarpornotarp100534Dripw/lowpermeability tarp2450Nonfieldsoil (structural/post-harvest)61Fumigation methods are described in detail in the text.2DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.3DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 48Table 21. Estimates of pesticide VOC emissions without application method adjustment factors (unadjusted standard EPs) for 1990,1991, and 2004. The 1991 goal is a 20% reduction of the 1991 emissions.NonattainmentAreaYearUnadjustedVOC Emissions,May– October (tons/day)1,3-DChloropicrinMethylBromideMetamDazometNaTetrathiocarbonate1OtherPesticidesTotalEmissions19900.0000.0360.4000.0220.0000.0002.4432.901Sacramento19910.0000.0350.3190.0130.0000.0002.7493.116Metro20040.0870.0070.0610.0090.0000.0001.2051.3691991goal2.49319900.0050.2085.1582.0170.0000.00615.35022.744San Joaquin19910.0000.3017.4931.4610.0000.00012.85322.108Valley20044.5500.3202.3646.2800.0250.11311.66925.3211991goal17.68619900.0000.0110.9020.0100.0000.0000.3151.238SoutheastDesert19910.0020.0140.4140.0190.0000.0000.3810.83020040.0250.0940.2960.8320.0110.0050.2371.5001991goal0.66419900.0000.9292.7850.1600.0000.0010.6334.508Ventura19910.0000.7452.5310.0850.0000.0000.5543.91520041.5433.3223.3170.4820.0090.0000.6409.3131991goal3.13219900.0000.1749.2480.0040.0000.0001.42610.852South Coast19910.0050.1663.4890.0400.0000.0001.4665.16620040.1980.4490.6690.0420.0240.0001.2172.5991991goal4.1331Sodium(Na) tetrathiocarbonate.John S. Sanders, Ph.D.September 29, 2007Page 49Table 22. Summary of fumigant application method adjustment factors.Fumigation Method1%of AmountApplied1,3-DChloropicrinMethylBromideMetam2Dazomet2NaTetrathiocarbonate3Shallow injection w/highpermeability tarpornotarp-broadcast656474notapplicablenotapplicablenotapplicableShallow injection w/ low permeability tarpbroadcastnotapplicable4448notapplicablenotapplicablenotapplicableShallow injection w/highpermeability tarpornotarp-bednotapplicable6410077notapplicablenotapplicableShallow injection w/ low permeability tarp-bednotapplicable64100notapplicablenotapplicablenotapplicableShallow injection w/2water treatmentsnotapplicablenotapplicablenotapplicable28notapplicablenotapplicableShallow injectionw/3watertreatments4443notapplicable21notapplicablenotapplicableDeep injectionw/ highpermeability tarpornotarp-broadcast266474notapplicablenotapplicablenotapplicableDeep injectionw/ lowpermeability tarp-broadcastnotapplicable4448notapplicablenotapplicablenotapplicableRotovate/rototill/soil cappingnotapplicablenotapplicablenotapplicable1417notapplicableSprinklernotapplicablenotapplicablenotapplicable77notapplicable10Sprinklerw/2water treatmentsnotapplicablenotapplicablenotapplicable28notapplicablenotapplicableSprinklerw/ 3water treatmentsnotapplicablenotapplicablenotapplicable21notapplicablenotapplicableFloodnotapplicablenotapplicablenotapplicable77notapplicable10Dripw/highpermeabilitytarpornotarp2912notapplicable9notapplicable10Dripw/lowpermeability tarpnotapplicable12notapplicable9notapplicablenotapplicableNonfieldsoil (structural/post-harvest)notapplicablenotapplicable100notapplicablenotapplicablenotapplicable1Fumigation methods are described indetail in DPR’s proposed regulations.2DPR assumes 100% conversion ofmetamand dazomet to MITC and percentages are relative tothe amount of MITC applied.3DPR assumes 100% conversion ofsodium(Na)tetrathiocarbonate to carbondisulfide and percentages are relative to the amount ofcarbon disulfide applied.John S. Sanders, Ph.D.September 29, 2007Page 50Table 23. Estimates of pesticide VOC emissionswith application method adjustmentfactors for 1990, 1991, 2004, and predicted 2004emissions if only “low-emission” methodsare used under the 2008 regulations. The goalis a 20% reduction of the 1991 emissions.NonattainmentAreaYearField AdjustedVOCEmissions,May–October (tons/day)1,3-DChloropicrinMethylBromideMetamDazometNaTetrathiocarbonate1OtherPesticides2TotalEmissionsSacramentoMetro19900.0000.0230.3470.0120.0000.0002.4432.82519910.0000.0220.2770.0070.0000.0002.7493.05520040.0230.0030.0670.0050.0000.0001.2051.3022004low30.0230.0030.0660.0020.0000.0001.2051.298Goal(1991)2.444San JoaquinValley19900.0000.1334.2251.1500.0000.00115.35020.85919910.0000.1936.1100.8230.0000.00012.85319.97920041.2260.1491.2012.9010.0040.01111.66917.1622004low31.2060.1441.1491.1440.0040.01111.66915.328Goal (1991)15.984SoutheastDesert19900.0000.0070.8210.0070.0000.0000.3151.15119910.0020.0090.3760.0130.0000.0000.3810.78020040.0080.0440.1760.5330.0020.0000.2371.0002004low30.0070.0380.1420.1830.0020.0000.2370.610Goal(1991)0.624Ventura19900.0000.5942.4350.0900.0000.0000.6333.75619910.0000.4772.2150.0480.0000.0000.5543.29320040.4641.4272.2240.0690.0020.0000.6404.8262004low30.4581.2361.5930.0780.0020.0000.6404.005Goal(1991)2.634South Coast19900.0000.1119.2080.0020.0000.0001.42610.74719910.0050.1063.4660.0220.0000.0001.4665.06520040.0580.1640.4550.0170.0040.0001.2171.9152004low30.0580.1660.3420.0070.0040.0001.2171.794Goal(1991)4.0521Sodium(Na) tetrathiocarbonate.2VOC emissions for other pesticides (nonfumigants) use the EPs without any adjustment for field conditions.32004 low shows the predicted 2004 emissions if all fumigantapplications used a “low-emission” application method.John S. Sanders, Ph.D.September 29, 2007Page 51Table 24. Maximumfumigant emissions (fumigant emission limit) that would achieve the goal of a 20% reductionof the 1991 pesticideVOC emissions, assuming VOC emissions fromnonfumigant (other) pesticides remain the sameas 2004. The 2004 fumigant emissionsand the percentage reduction of these emissions needed to achieve the emissions goal are also shown.Nonattainment AreaField Adjusted VOC Emissions, May–October (tons/day)Additional 2004Fumigant EmissionsReduction Needed toAchieve Goal (%)2EmissionsGoal2004 Emissions FromOther PesticidesMax FumigantEmissions ThatAchieve Goal12004 FumigantEmissionsSacramento Metro2.4441.2051.2390.098-1164 (goal achieved)San Joaquin Valley15.98411.6694.3155.49221Southeast Desert0.6240.2370.3870.76349Ventura2.6340.6401.9944.18652South Coast4.0521.2172.8350.698-306 (goal achieved)1MaximumFumigant Emissions That Achieve Goal calculated by subtracting the 2004 Emissions FromOther Pesticides fromtheEmissions Goal.2% reduction based on the difference between the Max Fumigant Emissions That AchieveGoal and the 2004 Fumigant Emissions, andassuming emissions from other pesticides remain the sameas2004. Examples: The 2004 fumigant emissions in Sacramento Metro couldincrease by 1164% and still meet the emissionsgoal. The 2004 fumigant emissions in SanJoaquin Valley must decrease by 21% inorderto meet the emissions goal.