### Reducing Volatile Organic Com pound Emissions from Pesticides: Analysis of Alternatives for Field Fumigation Methods

Summary

California’s ozone State Implementation Plan (S IP) for the federal Clean Air Act contains a pesticide element that requires the Department of Pesticide Regulation (DPR) to develop and maintain an emission inventory to track vol atile organic compound (VOC) emissions from pesticides, and to reduce pesticide VOC emissi ons by 20 percent from the 1990 base year in four ozone nonattainment areas (NAA), and by 12 percent in a fifth NAA. To compile the emission inventory, DPR multiples the fraction of a pesticide product estimated to be VOCs by the amount of that product applied. The calcu lation is adjusted for fumigants to account for how emissions vary depending on fumi gation method, based on monitoring data. The reduction goals have been met in all NAAs for the last two years of the inventory.

Between January 2008 and May 2011, DPR adopted a series of regulat ions to reduce VOC emissions from fumigant pesticides. One part of the regulations reduces VOC emissions by requiring low-emission fumigation methods in certain NAAs. The regulations include the following types of fumigation method restric tions based on monitoring data: fumigant introduction method, tarping, pre- fumigation soil moisture, post-fumigation water treatments, and application rate limits. DPR developed the restrictions based on an analysis of possible

low-emission method alternatives that incl uded VOC reduction effectiveness, technical feasibility and availability, compliance and enfo rceability, pest management effectiveness,

effect on other health or environmental concer ns, and cost. In general, the regulations for low-emission fumigation methods require tarping, post-fumiga tion water treatments, or application through drip irriga tion systems. Based on field monitoring data, DPR estimated that the emissions from low-emission fumiga tion methods were 9-48 percent of the amount applied, and high-emission fumi gation methods were 64-100 percent of the amount applied, except for methyl iodide. The emission inventory indicated th at some growers adopted lowemission fumigation methods prior to the regu lations. The remaining growers who changed fumigation methods to comply with the regul ations reduced fumigant VOC emissions by approximately one-third. The estimated re duction cost was $17,000 to $70,000 per ton of VOCs, based on 2007 prices.

DPR is taking additional steps to reduce VOC emissions. The VOC regulations also include a fumigant emission limit for the Ventura NAA at least until 2012. This system is also a backstop measure in the event low-emission fu migation methods are insufficient to achieve the SIP goals for the other NAAs. DPR is worki ng with pesticide registrants to reformulate certain pesticide products that contain high amounts of so lvents. DPR and others are conducting research to further reduce VOC emi ssions from pesticides, such as additional changes to fumigation methods, soil amendments that degrade fumigants, and growing crops without fumigants. Other measures that would reduce VOC emissions are infeasible at this time for several reasons, such as incompatibility with fumigant propert ies, ineffective pest control, lack of equipment or other resources, ad verse health or environmental effects, or lack of legal authority. The infeasible measures in clude prohibiting use of fumigants, requiring the

1lowest emitting fumigation met hod, requiring integrated pest ma nagement or use of certain pesticides, or reducing crop oils.



### Introduction

DPR has broad authority to regulate sales a nd use of pesticides unde r various federal and state laws. DPR regulates pesticid e sales through its registration process. Similar to the U.S. Environmental Protection Agency’s (EPA’s ) process, pesticide manufacturers and formulators (registrants) mu st submit and DPR must eval uate studies on toxicity, environmental effects, chemistry, and other pesticide characteristics. DPR registers a pesticide product (approves for sale) if the studie s are acceptable and use is not anticipated to result in unacceptable risk to human health or the environment. Once registered, DPR can request additional studie s and actions by registrants using th e reevaluation process specified in state law. Application or us e of pesticides is regulated at several levels. All pesticide products must have a U.S. EPA-approved label that describes the maximum application rate, methods of application, crops that can be treate d, safety precautions, and other requirements. Labels are enforceable documents, and making pesticide applications contrary to label

directions is a violation of both state and federal law. DPR also develops and implements state regulations that can be more restric tive than the label. Under state law, county agricultural commissioners can also impos e additional use requirements through the permitting process required for certain pesticides (restricted materials), based on an evaluation of local conditions. Growers and ap plicators are required to follow the most stringent use requirements, whether specified by labels, state regulations, or county permit conditions. County agricultural commissioners are responsible for enforcing all pesticide use requirements, under DPR oversight.

DPR has used its authority to regulate VOC emissions from pesticides. VOCs and nitrogen oxides react with sunlight in the atmosphere to create ground-level ozone, which is harmful to human health and vegetation when presen t at high enough concentrations. Under the federal Clean Air Act, California must meet national standards for airborne pollutants, including ozone, and must specify how it will achieve these goals in a federally approved SIP. California’s SIP contains a pesticide elemen t that requires DPR to develop and maintain an emission inventory to track pesticide VOC emissions, and to reduce emissions by 20 percent from the 1990 base year in four oz one nonattainment areas (NAA), and by 12 percent

in a fifth NAA. These five NAAs are defined as areas that do not meet the National Ambient Air Quality Standards for ozone as designated in the Clean Air Act. The SIP specifies that DPR is responsible for tracking and reducing pesticide VOC emi ssions from agricultural use and commercial structural use (applications by structural pest control businesses), while the Air Resources Board (ARB) is responsible for VOC emissions from the home use of pesticides as part of thei r consumer products program.

To DPR’s knowledge, no other state has measures to reduce VOC emissions from pesticides, and if one did they would likely be different from DPR’s measures du e to California’s unique pesticide use permit program. DPR’s VOC program is a hybrid air pollution and pesticide regulatory program. Hence, it has some commonali ties with other air po llution and pesticide programs, but differs in several respects. Pe sticides are considered area sources of air

2pollution, as opposed to mobile sources (e.g., motor vehicles), or stationa ry sources (e.g., oil wells). Additionally, pesticides are intentionally introduced into the environment to control harmful pests, as opposed to waste discharges (e.g., smokestacks). Most pesticide regulatory programs focus on potential toxic effects from the active ingredients in pesticide products. In contrast, DPR’s VOC program does not consider toxic effects, but does consider both active and inert ingredients in pesticide products, and generally classifies th e products as fumigants or nonfumigants. Fumigant pesticide products usually contain approximately 100 percent active ingredients (some contain a small per centage of a warning agent), and the active ingredients are gases under normal envir onmental conditions. Nonfumigant pesticide products are liquids or solids containing both active and inert ingredients, and many such products include VOC solvents as inert ingred ients, particularly products formulated as

emulsifiable concentrates.

In April 2009, DPR adopted amendments to th e pesticide SIP element for the San Joaquin Valley NAA. These amendments included a commitment to implement restrictions on agricultural fumigation methods and VOC emissi ons of nonfumigant pes ticides. In addition, DPR proposed to commit to manage pesticide VOC emissions, to ensure that they do not exceed 18.1 tons/day in the San Joaquin Valley area. The 18.1 tons/day limit is equivalent to a 12 percent reduction from the 1990 base year, and “freezes” DPR’s emissions estimation methodology and pesticide emissions for 1990. The following web page contains the complete pesticide SIP and supporting documents: http://www.cdpr.ca.gov/docs/emon/voc s/vocproj/voc_state_imp_plan.htm

Between January 2008 and May 2011, DPR adopted a series of regulat ions to reduce VOC emissions from fumigant pesticides. Title 3 of the California Code of Regulations (3 CCR), section 6452.2, includes specific emission target levels (VOC regulation benchmarks) for each of the five NAAs, equivalent to the SI P obligation of a 12 percent or 20 percent reduction. The regulations reduce VOC emissions by requiring low-emission fumigation methods in certain NAAs. If, in spite of thes e application method requirements, pesticide VOC emissions exceed specified trigger levels, DP R is required to ensure that the benchmark is achieved by establishing a fumigant limit. The fumigant limit is determined by subtracting the estimated nonfumigant emissions from the regulatory benchmark, basing the nonfumigant emissions estimate on VOC emission i nventory data from previous years. The following web page contains all of the fumiga nt VOC regulations a nd supporting documents: http://www.cdpr.ca.gov/docs/em on/vocs/vocproj/reg_actions.htm

In October 2009, ARB submitted DPR’s SIP amendments and three sets of fumigant VOC regulations to U.S. EPA. In July 2011, ARB submitted two additional sets of DPR fumigant VOC regulations to U.S. EPA. To assist U.S. EPA with its review, this document contains more detailed information than previously submitted on DPR’s evaluation of fumigation methods, and information on other potential pesticide VOC reduction measures. Additionally, this document includes mo re recent emission inventory data.

3

### Background Information on Fumigants

Fumigants are most commonly used to treat soil in agricultural fields prior to planting, but harvested commodities and other sites can also be fumigated. These other types of fumigations are not agricultural or structural uses, so they are not included in DPR’s VOC program, and are not included in the fumigant regulations. The nonagricultural uses of fumigants are very low compared to the agricultural uses.

Field fumigants include products containing one or more of the following active ingredients:

• 1,3-dichloropropene

• Chloropicrin

• Methyl bromide

• Methyl iodide (first registered in California in December 2010)

• Sodium tetrathiocarbonate (because it generate s carbon disulfide as a pesticidal agent)

• Active ingredients that generate methyl isothiocyanate (MITC) as the pesticidal agent (dazomet, metam-potassium, and metam-sodium).

Fumigants differ in several impor tant aspects from other pestic ides. As gases, fumigants are much more volatile than other pesticides. Sinc e they disperse so readily and target large volumes of soil, fumigants are usually applie d at rates of severa l hundred pounds of active ingredient per acre, while most other pesticides are applied at rates of a few pounds or ounces per acre. Fumigants are applied to fallow fields, prior to planting, while most other pesticides are applied to growing crops. Fu migants are applied once per year at most to any individual field, and only once for the lifetime of an or chard or vineyard. Many other pesticides are applied multiple times during the year. Mo st fumigant products contain only active ingredients, and no inert ingred ients. Most other pesticide pr oducts contain a mixture of active and inert ingredients. Most pesticides target specific pests, such as a particular type of insect or weed. Fumigants can control a wide variety of pests in th e soil, including most weeds, nematodes, insects, and diseases. However, due to the co st of the product and controls to reduce health effects, fumi gant application rates are norm ally minimized to control only certain targeted pests. For example, MITC fumigants are primarily used to control weeds and chloropicrin primarily mitigates diseases. Becau se of the variable effectiveness, and to prevent pest resistance to a single pesticide, prohibiting all but the lowest emitting fumigant

is infeasible.

Field fumigant application methods are differe nt from other pesticides. Most fumigation methods either use special tractors to inje ct fumigant below the soil surface, or apply fumigant with water through an irrigation sy stem (chemigation). Due to the specialized equipment required, pest control businesses rather than growers conduct most of the fumigations. Fumigant applicati ons cost more than most othe r pesticides, so fumigants are economically feasible only for high-value crops . Crops that commonly us e fumigants prior to planting include almonds, carrots, flowers, grap es, nursery crops, raspberries, strawberries, sweet potatoes, tomatoes, and walnuts. The California regions with highe st fumigant use are the Central Coast region between Ventura a nd Santa Cruz, and the San Joaquin Valley. While fumigations occur throughout the year, p eak use is during the summer and fall for most crops and regions.

4Like most other pesticides, fumigants are cons idered toxic chemicals. Since they are also volatile and applied at large rate s, the risk from toxic exposur e to fumigants is higher than most other pesticides. Due to this risk, U.S. EPA and DPR have implemented regulatory requirements to control exposures to both worker s and the public. Fumigant label revisions in 2010 include “good agricultural practices” requiring specific soil preparation and soil moisture levels, equipment calibration and equi pment safeguards, and other restrictions. In the early 1990s, DPR and county agricultural commissioners began implementing a series of regulatory requirements for a pplication methods, use limits, buffer zones, and worker protections. The label and othe r regulatory requirements to address exposures complement the VOC regulations. When possible, DPR de veloped measures to reduce fumigant VOC emissions as well as reduce toxic exposures. All of the field fumigants are restricted materials, requiring additional scrutiny and possible permit cond itions by county agricultural commissioners. Based on inspections of applic ations by county agricultural commissioners, compliance with the regulatory requirements is higher for fumigants than most other pesticides. Summary statistics of pesticide insp ections are available by county and year at the following website: http://www.cdpr.ca.gov/docs/c ounty/statistics/index.cfm

.

U.S. EPA plans to implement additional label changes for field fumigants in 2011. These changes will include buffer zones to protect bys tanders. The buffer zone distances depend in part on emission estimates for various fumi gation practices. U.S. EPA’s estimates of emissions, particularly “buffer zone credits” assigned to various fu migation practices are based largely on modeling using CHAIN2D th at was modified by the Chloropicrin

Manufacturers Task Force. DPR did not use U.S. EPA’s emission estimates for several reasons: 1) U.S. EPA published its emissions estimates after the fumigant VOC regulations went into effect. 2) U.S. EPA and DPR rely on peak emissions over one day or less to

determine the size of buffer zones. VOC estimat es are based on total emissions over several days or weeks. 3) DPR decided not to use the modified CHAIN2D model for the reasons specified below. In brief, the modeling system is not validated. Major features of the model such as drip irrigation or the dynamic boundary layer were not tested. The testing that was done utilized an unsupported ‘shank trace’ featur e to arbitrarily make model results fit more closely to measured results. A hydraulic pa rameter estimation scheme gives incorrect estimates. The general approach, which uses av erage texture class hydra ulic parameters, may give incorrect results. DPR re lied on field monitoring data for its emission estimates and reductions associated with various applicati on practices. As discussed in the section on fumigation method options, some of DPR’s emission reduction estimates based on monitoring data differ from U. S. EPA’s buffer zone credits based on CHAIN2D modeling.

Also discussed in a later section is DPR’s attempt to develop its own model to estimate fumigant emissions. The following document describes U.S. EPA’s emission estimates for buffer zone purposes: http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2007-

0350-0173

. The following document describes DPR’s review of U.S. EPA’s estimates: http://www.regulations.gov/#!docum entDetail;D=EPA-HQ-OPP-2007-0350-0285.1

.

Measured in pounds, fumigants represent appr oximately 20 percent of all agricultural pesticides used in California. However, use of fumigants has changed dramatically since the

5early 1990s (Figure 3), and will likely continue to change for several reasons. Under the Montreal Protocol and Clean Air Act, U.S. EPA began phasing out production and importation of methyl bromide in the late 1990s due to stratospheric oz one depletion effects. In 1990, DPR directed the county agricultural commissioners to resci nd all permits for 1,3- dichloropropene due to exposure concerns. Th ese actions caused MI TC pesticides and chloropicrin use to increase. Use of 1,3-dichloropropene subsequently increased since its reintroduction in the mid-1990s, with revised regulatory requirements. However, recent decreased production of 1,3-dichloropropene due to the recession has led to decreased use of that fumigant in the last two years. DPR first registered methyl iodide in December 2010, and its introduction could change use patterns ev en more. These actions, as well as other regulatory requirements, have led to increased cost for all fumigants.



### Pesticide VOC Emission Inventory

DPR prepares an annual estimate of VOC em issions from agricultural and commercial structural pesticide applications. There is an emission inventory for each year since 1990, the base year. Pesticide applications in five NAAs are included: Sacramento Metro, San Joaquin Valley, South Coast, Southeast Desert, and Ventura (Figure 1). Only agricultural and commercial structural pesticide applicatio ns are included. ARB tracks emissions from pesticides in consumer products. DPR uses data on VOC content and pesticide use to estimate emissions from reported agricultural an d commercial structural applications in each NAA. The inventory focuses on May 1 through October 31, the peak ozone season in

California.

To estimate the VOC contribution of individual agricultural and struct ural use pesticides, DPR multiples the fraction of a pesticide product estimated to be VOCs (its “emission potential”) by the amount of that product applied.

Estimated VOC emissions = (Emission potential of the product) X (Pounds of pesticide product applied)

Pesticide use reports provide th e amount of product used. Californi a requires full reporting of all agricultural pesticide use and the use of pes ticides by pest control businesses. The reports document the product applied, the amount appl ied, date applied, location (within a one square mile section), crop treated, number of acres treated, and other information.

DPR has several methods to determine the em ission potential. The preferred way is through laboratory analysis, using a standardized method approved by DPR (thermogravimetric analysis). When it is not available, DPR uses other approaches to decide emission potentials.

• Using the VOC emission potential already meas ured in TGA analysis of an identical or nearly identical pesticide product.

• Using the confidential statement of form ula on file with DPR to find out the percentage of water and other inorganic chemicals in the pr oduct. This is subtracted and the remainder is assumed to produce emissions that must be included in the inventory.

6• Assigning an estimated value based on an ev aluation of a product’s unique chemistry and composition. DPR takes this approach for high-use products with well-known chemical properties.

• Assigning a default emission potential at a representative level, based on measured

data that reflect the behavior of similarly formulated products.

Because DPR has monitoring data, the calculation is adjusted for fumigants to account for how emissions vary depending on fumigation method (Application Method Adjustment Factor, AMAF, or emission rating). AMAFs have been determined from field study data and are active ingredient and app lication method specific (Table 1). Since the AMAFs are based on field measured data for specific applicati on methods and fumigants, they yield more refined estimates of fumigant VOC emissi ons than the previous unadjusted emission

estimates.

Estimated fumigant VOC emissions = lbs of product used x EP x AMAF

Nonfumigant product emissions are not currently adju sted for application method or other

field factors due to a lack of da ta to support such adjustments.

Usually there are several different types of application methods used for a particular fumigant in any particular NAA. Each method of use (e.g. drip, sprinkler, shank, tarp, etc.) represents a fraction of the tota l number of methods used and is referred to as the method use

fraction. The sum of all method use fractions fo r any particular (NAA/fumigant) combination is one. Use practices change over time so that different method use fractions are used for the base year (1990) as opposed to more recent inventory years. For 1990, 2005, 2006, and 2007, method use fractions were determined in a number of different ways. For 1,3- dichloropropene the method use fractions are determined from use data collected by the registrant in support of DPR’s township a pplication caps; for metam sodium and metam potassium grower/applicator surv eys were conducted to determine types of applications for different crops and areas. Methyl bromide and chloropicrin method use fractions are based on expert opinion and regulatory history. Finall y, method use fractions for dazomet and sodium tetrathiocarbonate equal one because the AMAFs for each of these two fumigants are constant, independent of app lication method. See Attachment 1a (DPR memorandum from Barry, Spurlock and Segawa to Sanders, date d September 29, 2007) for a detailed discussion

of how method use fractions and AMAFs were determined.

The 2008 fumigant VOC regulations included a change to pesticide use reports (3 CCR sections 6624 and 6626) that requires record ing the specific applic ation method for each fumigation within NAAs. The method use fractions for 2008 and later years are calculated using the fumigation method documented in pestic ide use reports rather than the surrogate data described above. Some pesticide use re ports for 2008 and later years are missing the identification of the application method. In th ese cases, DPR assumed that the application method with the highest AMAF allowed by the re gulations for that fumigant was used. See the following web page for more details on the methodology to calcu late pesticide VOC

emissions: http://www.cdpr.ca.gov/docs/emon/ vocs/vocproj/voc_method_est.htm

7The 2008 fumigant VOC regulations (3 CCR section 6452.4) require DPR to publish its emission inventory annually. The an nual reports are available at: http://www.cdpr.ca.gov/docs/emon/vocs/vocproj/voc_data_analysis.htm . The most recent data is for 2009, and Figure 2 shows the pesticid e VOC emissions relative to the SIP goals for 2009 and earlier years. The 2009 pesticide VOC emissions for all five NAAs complied with the SIP goals, ranging from 33 to 89 per cent less than emissions in the 1990 base year. Relative to 2008, pesticide VOC emissions in 2009 ranged from a 4 percent increase to a 47 percent decrease, depending on the NAA.

• Adjusted emissions in 2009 in the Sacramento Metro continue to decline and fell to below 1 tons/day. Nonfumigants represente d 87 percent of the total, and the total remaining well below the SIP goal.

• Emissions in the South Coast NAA also de creased slightly over 2008 values and remain well below the SIP goal. Three quarters of the total adjusted VOC emissions came from nonfumigants.

• In 2009, fumigants accounted for less than ha lf of VOC emissions in the Southeast Desert, down slightly from 2008. Total VOC emissions in 2009 decreased by almost 50 percent from 2008 and continue to meet the SIP goal.

• 2009 VOC emissions in the Ventura NAA increased by 0.072 tons/day from the previous year but continue to m eet the regulatory goal for 2010, 2011 and 2012. Seventy five percent of emi ssions come from fumigants.

• In the San Joaquin Valley NAA, nonfumigants accounted for approximately three quarters of the total VOC emissions in 2009. In this NAA, VOC emissions decreased from 2008 to 2009 by about 7 percent, and continue to be below the SIP goal.

As calculated for the emission inventory, fu migant emissions depend on the fumigant, fumigation method, and amount applied (applicati on rate in pounds per acre and number of acres treated). Table 2 compar es fumigant use and emissions prior to and after the 2008 fumigant regulations (2006-2007 compared to 2008-2009, annual average for May-October). May-October fumigant VOC emissions decl ined 48-81 percent where the regulations required low-emission fumigation methods, de pending on NAA. Some growers adopted lowemission fumigation methods prior to the regu lations. The remaining growers who changed to low-emission fumigation methods to comply with the regulations accounted for a 31-32 percent decrease, and less use accounted for 17-49 percent decrease, depending on NAA. The fumigant emission limit for Ventura likely contributed to the decr ease in use for that NAA.

Table 3 shows that the decrease in use was pr imarily due to less acreage fumigated in all NAAs after the fumigant VOC regulations were effective in 2008. Between 2006-2007 and 2008-2009, the May-October fumigated acreage decreased by 17 percent (49,242 acres to 40,862 acres) in the San Joaquin Valley NAA, by 33 percent in the Southeast Desert NAA (3,456 acres to 2,332 acres), and by 24 percen t in the Ventura NAA (15,497 acres to 11,833 acres). The percentage decrease in fumigated acreage for the entire year was less than the May-October period, indicating th at shifting fumigation dates outside May-October caused part of the decrease in VOC emissions.

8

### Evaluation of Field Fumigation Method Options

The key provision in the fumiga nt VOC regulations that achieve s emission reductions is the requirement for “low-emission” fumigation me thods in the San Joaquin Valley, Southeast Desert, and Ventura NAAs dur ing May-October. The de signation of low-emission fumigation methods is based on the AMAF a nd maximum allowed appl ication rate. Field monitoring has demonstrated that fumigant emissi ons vary with several factors, but primarily with fumigant, fumigation method, and application rate. Several methods have been used to estimate fumigant emissions, including laboratory experiments, field measurements on small plots (less than one acre), field measurements of large plots (one acre or more), as well as computer modeling. DPR has relied on field me asurements of large plots for emission estimates because they are most similar to commercial fumigations. Research continues on the other methods, but comparisons so far i ndicate that the other methods do not always agree with field measurements of large plots.

Most of the low-emission methods specified by the regulations were based on field studies conducted by registrants, agricultural commodity groups, the University of California, and the U.S. Department of Agriculture (USDA) . They developed the fumigation methods and

measured the emissions. DPR and ARB have also monitored several fumigations to confirm the emissions. The studies DPR relied upon for its emission estimates are listed in Attachments 1a and 1b for each fumigant. (Attachm ent 1a was peer reviewed as part of the rulemaking process.) Appendix 4 to Attachment 1a lists other studies on fumigant emissions, but not used by DPR and the reasons for excl uding the data. Attachment 1a describes the

studies available at the time the fumigant VOC regulations were first developed in 2007.

Attachment 1b describes the studies that DPR has evaluated since then. Additional studies which DPR has not yet evaluated are discussed in the Current Resear ch on Fumigant VOC

Emission Reduction section.

The fumigant VOC regulations exempt certain small, specialized fumigations, such as individual tree-hole replant a pplications less than one acre. These fumigations have negligible emissions due to very low use. These applications are infrequent and small compared to other fumigations. Including these applications would have greatly complicated the regulations, with negligib le reduction in VOC emissions.

DPR’s regulations for field fumigation methods are described in 3 CCR sections 6446.1 for methyl iodide; 6447.3 for methyl bromid e; 6448.1 for 1,3-dichloropropene; 6449.1 for chloropicrin; 6450.1 for metam-sodium a nd metam-potassium; 6450.2 for dazomet; and 6451.1 for sodium tetrathiocarbonate and include the following types of fumigation method restrictions based on the monitoring data:

• Fumigant introduction method

• Tarping

• Pre-fumigation soil moisture

• Post-fumigation water treatments

• Application rate

9DPR considered, but did not incl ude the following types of fumi gation method restrictions in the regulations:

• Temperature and other weather conditions

• Soil characteristics

• Soil amendments

• Soil preparation, equipment prep aration, general procedures

DPR considered the following factors in de veloping the fumigation method requirements:

• VOC reduction effectiveness

• Technical feasibility and availability

• Compliance and enforceability

• Pest management effectiveness

• Effect on other health or environmental concerns

• Cost

As summarized in Table 4 and described be low, DPR has designated several fumigation

methods as low-emission. Based on monitori ng data, the emissions from low-emission fumigation methods were 9-48 percent of th e amount applied, and high-emission fumigation methods were 64-100 percent of the amount app lied, with the exception of methyl iodide (Table 1). Requiring the lowest emission fumigation method is in feasible for several reasons: 1) a single method is not physic ally possible for all fumigants; 2) a single method is not effective in reducing VOC emissions for all fumi gants; 3) a single method is not effective against all target pests for all crops; and 4) the equipment and other resources are not always available or very costly.

Evaluation of Fumigation Methods – Introduction Methods

There are two main methods to introduce fumiga nt into the soil: chemigation or tractor. Fumigant introduction methods va ry by fumigant and crop. Some methods are feasible for some fumigants and crops, but not others. In general, drip chemigation methods have lower emissions than tractor methods (Table 1 and Attachment 1a). However, methyl bromide’s volatility is too high and its water solubility is too low to be reta ined in water, so chemigation is not technically feasible for that fumigant. Dr ip irrigation systems are costly to install and maintain. In general, they are economically feasible for fields where drip systems will be used for irrigation, not just a fumigant delivery system, and where the drip system can be installed prior to planting and used for fumiga tion. Additionally, drip chemigation is usually only effective for crops where the target pest is at shallow depths (1 foot or less). Strawberries and raspberries are the most common crops where these conditions occur and fumigations use drip chemigation. Based on the monitoring data, all of the drip chemigation methods are designated as low-emission.

MITC-generating pesticides and sodium tetrathiocarbonate are unusual because they can be applied using other chemigation methods, such as sprinkler or fl ood. The parent compounds metam-sodium, metam-potassium, and sodium te trathiocarbonate are non-volatile salts, so they are easily applied through irrigation systems. Moreover, it takes several minutes to several hours for the parent compound to convert to MITC or carbon disulfide. This delay

10allows MITC and carbon disulfide pesticides to be applied through irrigation systems and still minimize emissions. In many cases, non-dr ip chemigation fumigations are less costly and have greater pest management effectiven ess than drip applica tions. Other irrigation equipment is less costly than drip, and a pplications are usuall y more uniform. Many irrigation systems are portable and can be m oved between fields. Like drip chemigation, other chemigation methods are suitable only for crops where the target pest is located at shallow depths. MITC sprinkler chemigations are most common for carrots and potatoes in the San Joaquin Valley and S outheast Desert NAAs. As discussed below, sprinkler fumigations with one post-fumi gation water treatment is designated a high-emission method. Sprinkler fumigations with two or more post- fumigation water treatments are designated

low-emission methods. Sodium tetrathiocarbon ate and other chemigation methods are not commonly used.

With the exception of sodium tetr athiocarbonate, all fumigants can be applied by a tractor. In most cases, fumigants applied with a tractor are injected beneath the soil surface through

shanks attached to the back of the tractor. So me available data seems to support the theory that emissions may vary with depth. Howe ver, DPR’s analysis of methyl bromide applications and other fumigant data show that emissions vary significantly depending upon whether application occurs to a flat field (b roadcast) or to a field that has been bedded (Attachment 2 – DPR memorandum from Barry to Sanders, dated December 2, 1999). In general, emissions are lower with flat fields. Fumigants are normally in jected at 6-24 inches beneath the soil surface. The dept h of crop roots and location of the target pest determines the depth of injection. Fumigant s are usually injected at 6-12 inches for crops with shallow roots, such as strawberries and vegetables. Fu migants are usually inject ed at 18-24 inches for crops with deep roots, such as nut orchards and grapes. Injection depth cannot be increased to

decrease emissions without losi ng pest management effectiv eness. Also, increasing depth does not always decrease emissions. The availabl e data for methyl bromide indicates that depth has no significant effect on emissions, at least within a 10-24 inch depth (Attachment 2). This is likely due to the type of shank and tractor implements, and high soil moisture. Injection at greater depths requires wider shanks. The channel in the soil created by the shanks (shank trace) can be a pathway to the surface, so the wider the channel the higher the emissions. High soil moisture may increase this effect due to greater soil adhesiveness. Special shanks (e.g., Nobel plow ) are often used for shallo w injection to reduce this channeling effect. Nobel plows consist of a hor izontal wing attached to the vertical shank, with fumigant released along the wings and away from the channel created by the shank. Nobel plows are usually not feasib le for greater depths because the resistance is too high for tractors pull them through the soil. Applicator s have developed other tractor implements (e.g., compaction rollers) to di srupt or close the channel cr eated by the shanks. Broadcast fumigations are common for all crops and areas, particularly for nut orchards and grapes. Based on the monitoring data, deep injecti on is designated a low- emission method for 1,3- dichloropropene and some chloropicrin met hods. Deep injection is designated a highemission method for methyl bromide, unless accompanied with some other mitigation measure (e.g., tarping). MITC pesticides are usua lly not injected at deep depths because the primary target pests are w eeds at shallow soil depths.

11Tractor fumigations to be dded fields usually have higher emi ssions than flat fields (broadcast fumigations). Bedded fumigations usually cost less than broadcast fumigations because the fumigation and bed forming occurs in a single tractor operation, and th ey use less fumigant. For broadcast fumigations, the fumigation a nd bed forming require separate tractor operations. The higher emissions with bedded fumigations are partially offset by lower application rates. The entire fi eld is treated for a broadcast fumigation. In contrast, only the beds are treated for a bedded fumigation; the furrows are untreated. Therefore, the effective (or broadcast-equivalent) application rate is lower for a bedded field. Bedded shank fumigations are common for carrots and sweet potatoes in the San Joaquin Valley. Most bedded shank fumigation methods are designat ed as high-emission, unless accompanied with some other mitigation measure (e.g., tarping).

There are a few tractor fumigation methods for MI TC pesticides that do not involve injection

beneath the soil surface. These include rota ry tiller, power mulcher, and soil capping methods. These methods involve spraying a wa ter solution of metam-sodium or metampotassium on the surface of the soil, and then in corporating into the so il or placing untreated soil on top. The available data indicates than these methods have comparable or lower emissions than other methods (Attachment 1a). These methods are most commonly used for tomatoes in the San Joaquin Valley. Based on the available monitori ng data, most of the methods are designated as low-emission. The four th set of regulations effective in April 2011 added a drench method for MITC pesticides. Fo r this method, a tractor is used to spray a dilute solution of a MITC pestic ide on the top of the soil, at ve ry low application rates. This method is used for specialty crops, such as ci lantro, and has also b een designated as lowemission (Attachment 1b, Ratto Brothers deci sion). The tractor fumigation methods for dazomet are unique. This MITC pesticide is gran ular material, applied to the soil surface, then incorporated and watered-in. The label requires multiple water treatments. This pesticide has low use for all crops. Based on the monitoring data all dazomet application methods are designated low-emission.

As shown in Table 5, for fumigations that used a high-emission method, the estimated increased cost of using a low-emissi on method ranged $10-$2 510 per acre in 2007, depending on fumigant and fumigation method.

Other factors sometimes influence which fumigation method is used. Water supply is sometimes a factor in the feasibility of chemig ation methods. For fields that rely on surface water, irrigation canals may not have water at the time fumigations o ccur prior to planting. Equipment availability may also be a factor . For any one commodity, fumigations are often seasonal in nature, with most fumigations occurring in a few weeks. There may be an insufficient number of rigs to complete all fumigations using tractors. Equipment shortages can be exacerbated by weather conditions. The soil must have the appropriate moisture for fumigation. Fumigations cannot occur during or immediately after storms. Additionally,

tractors cannot enter fields that are too wet. Tractor fumi gations often cannot be done in high winds due to tarpaulin consider ations. If weather prevents fumigations for an extended period of time, the preferred fumigation method may not be available, so several different fumigation methods may be necessary.

12Evaluation of Fumigation Methods – Tarping

Tarping reduces emissions for most fumigants and fumigation methods. Tarping is feasible for all tractor shank injection methods and drip chemigation. Tarping is physically impossible for most other methods, such as rotary tiller, sprinkler, and flood. The most common tarpaulin is high density polyethylene , generally 1.0-1.5 mil th ick, and is sometimes referred to as the standard tarpaulin. Monitoring data indicates that the standard tarpaulin is effective in reducing emissions of chlor opicrin and methyl bromide, but not 1,3- dichloropropene (Attachment 1a). It is rare for MITC fumigations to use a tarp because of the relatively high cost of tarping co mpared to the cost of the fumi gant, and field monitoring data is not available. Tarpaulin cost s vary and have been increasing over the last several years. In general, tarped fumigations cost at least twice as much as untarped fumigations. The tarpaulins for fumigation are used once, and disposed, creating additional landfill waste. Tarpaulin fumigations for bedded fields are more efficient than flat fi eld fumigations because less is used and the tarpaulins usually remain in place for the entire growing season, acting as a mulch. Tarpaulins for flat fields are discar ded immediately after fumigation. As discussed in the section on research, newer tarpaulins such as “virtually impermeable film” or “totally impermeable film” may have somewhat misl eading names, but are more effective in reducing emissions than standard tarpaulins. Wh ile emission data is available for some low permeability tarpaulins and fumigants, data to ad dress exposure concerns is not available for most fumigants, so these tarpaulins are not wi dely used and prohibited for methyl bromide. For the upcoming label changes, U.S. EPA plans to assign a buffer zone credit of 10-60 percent, depending on fumigant and type of low permeability tarpaulin. The estimated increased cost of changing from a high-em ission untarped fumigation method to a lowemission standard tarpaulin fumigation me thod was $400 per acre in 2007 (Table 5).

For methyl iodide, California product labels require “highly retentive tarps” (virtually impermeable films or totally impermeable films approved by DPR and the registrant) for almost all fumigations. The highly retentive tarp s are primarily required to control exposures,

not reduce VOCs. To ensure that the buffer z ones provide adequate protection, DPR assumes that total methyl iodide emissi ons are 100 percent with highly re tentive tarps, as an interim assumption. Field studies on methyl iodide applications with hi ghly retentive tarps measured total emissions of approximately 30 percent of the amount applied, but DPR concluded that these studies likely underestimated the emi ssions (Attachment 1b, memo to John Sanders dated April 29, 2010). The registrant conducted a nother field emissions study to replace the earlier ones, and submitted a report to DPR in May 2011. DPR has not yet evaluated this report. Since it’s likely that ac tual methyl iodide emissions are less than 100 percent with highly retentive tarps and it is applied at relati vely low application rates (maximum label rate of 100 pounds per acre), DPR has designa ted these methods as low-emission.

Evaluation of Fumigation Methods – Pre-Fumigation Soil Moisture

In general, higher soil moisture reduces emission s, particularly when the moisture is higher near the soil surface (Attachment 1a, sections on 1,3-dichloropropene and chloropicrin). However, higher soil moisture also reduces effi cacy of the fumigant, by retarding dispersal. Compliance and enforcement of any soil moisture requirements are also problematic because

13there are no methods to easily and accurately measure soil moisture in the field. The U.S. EPA evaluated this issue in detail, and include d a soil moisture requirement of 50-75 percent of field capacity as one of the revisions to fumigant labels in December 2010. This requirement is more stringent and supersedes DPR’s regulations for soil moisture of 25-50 percent of field capacity. DPR’s regulations we re based on the soil moisture levels in the field monitoring studies used to establish the AMAFs. Both the fumigant labels and DPR’s regulations specify the USDA’s “feel” method fo r determining moisture. (NOTE: The fourth set of regulations includ es revisions that correct errors in the first set of re gulations for the method of determining soil moisture.

Evaluation of Fumigation Methods – Post-Fumigation Water Treatments

Applying water after the introdu ction of fumigant (post-fumi gation water treatment) is effective in reducing emissions of most fumiga nts (Table 1 and Attachment 1a, sections on chloropicrin and metam). Field monitoring of water treatments has not been conducted for methyl bromide, but it is likely ineffective due to methyl bromide’s higher volatility. The amount of water required and frequency of app lication reflects the practices used for the monitoring studies. Post-fumigation water treatmen ts are not always feasible. As discussed above, surface water may not be available prior to planting. Also, the ir rigation system must

cover the entire treated area. In the case of broadcast fumigations , this can only be done with overhead sprinklers, and not all growers have access to overhead sprink ler equipment. Postfumigation water treatments are most effectiv e for untarped applications. Water treatments are likely the least effective for broadcast fumi gations where the entire field is tarped, and this type of fumigation has not been monitore d. Another disadvantage for water treatments is the potential for water contamina tion. If too much water is ap plied, there is a potential for contamination of surface or ground water. The amount of water specified by the regulations is the amount and frequency used in the mon itoring studies, and DPR’ s evaluation concluded that surface runoff or percolation to ground water will not occur. (NOTE: The fourth set of regulations includes revisions that correct errors in the first se t of regulations for the water treatment requirements.) Post-fumigation wa ter treatments are most common for MITC sprinkler fumigations of carrot and potato fields in the San Joaquin Valley and Southeast Desert NAAs. Fumigations that use at least two or three post-fumigation water treatments are designated as low-emission. The estimated incr eased irrigation cost of the post-fumigation water treatments was $10 per acre in 2007, assuming the irrigation system is already in place. If the irrigation system must be rented the estimated increase d cost was $240 per acre in 2007 (Table 5).

To encourage the voluntary re duction of emissions, water tr eatments are one of three pesticide VOC measures for which the USDA – Natural Resources Conservation Service’s Environmental Quality Incentives Program (EQI P) provides matching funds to growers in

California.

Evaluation of Fumigation Methods – Application Rates

DPR assumes that application ra tes and emission rates are proporti onal, if the application rate increases by 2x the emission rate increases by 2x. The regulations specify the maximum

14allowed application rate for each fumigant, when less than the rate specified on labels. The maximum application rates were based on seve ral factors primarily related to exposure mitigation. 1) The rates do not exceed those used for the monitoring studies. 2) The rates resulted in buffer zone requirements (distances and field separation) that can be complied with and enforced. 3) The rates resulted in worker protections (e.g., respirators and work hour limits) that can be complied with and enforc ed. 4) The registrants supported the rates, indicating that they re sult in effective pest control. As discussed above, the effective application rate for bedded fumigations is less than broadcast fumigations because the furrows are untreated. Similarly, some growers will make “strip” fumigations, particularly for nut orchards or grapes. A strip fumigation is an application to a flat field, but every second or third tractor pass is left untreated. Trees and vines are planted only in the treated strips. Strip fumigations are less effective than normal br oadcast applicati ons, so are only feasible where the pest populati on is relatively low. The fourth set of regulations effective in April 2011 includes several fumigation methods for MITC pesticides that have been designated as low-emission in part due to low ap plication rates. This includes several night fumigation methods, and the drench method (A ttachment 1b, Responsible Farmers Coalition decision, Grimmway Farms decision, and Ratto Br others decision). DPR designated some of these methods as low-emission because the regu lations include a provision for approval if the emission rate (AMAF multiplied by the application rate) is no greater than the current lowemission methods.

Evaluation of Fumigation Methods – Te mperature and Other Weather Conditions

The soil and/or air temperature may influen ce emissions. Higher temperatures may have higher emissions. However, the analyses so far have not demonstrated a significant relationship between temperature and emi ssions (Attachment 3 – DPR memorandum from Barry to Segawa, dated January, 29, 2010, page 6). Temperature may influence emissions,

but the effect is too small to detect due to th e field-to-field variability and the effect of fumigation method. Since the monitoring did no t show an effect, the regulations do not include any requirements based on temperature.

With the exception of rainfall, most other weather conditions have minimal effect on emissions. However, sprinkler and tarped fumiga tions have label language that includes wind speed restrictions for these types of fumiga tions, so there are no requirements in DPR’s regulations.

Growers and applicators can only control the fumigant in troduction, so any weather restrictions beyond the application period are problematic. Monitoring data indicates that emissions continue for several days or week s after fumigant introdu ction, but no weather restrictions after fumigant introduction are possible.

Evaluation of Fumigation Methods – Soil Characteristics

The soil type and soil organic content may in fluence emissions. Soils consisting of finer particles (clay) are hypoth esized to have lower emissions than coarser soils (sand). Soil with higher organic content may have lower emissions. DPR is attempting to estimate the effect of

15soil characteristics using the HYDRUS computer model, as discussed in Current Research on Fumigant VOC Emission Reduction section. However, it’s likely that the effect, if any, will be minor due to similar soil types for fumi gations in California (Attachment 4 – DPR memorandum from Johnson and Spurlock to Segawa, dated January 23, 2009). Moreover, soil type can vary within a field, so determin ing compliance with any requirements may be problematic. For the upcoming label changes, U. S. EPA plans to assign a buffer zone credit of 10 percent for soils with greater than 27 percent clay content, and up to 30 percent depending on soil organic content.

Evaluation of Fumigation Methods – Soil Amendments

It’s possible that fertilizers or other soil amen dments affect emissions. Several studies have measured emissions comparing fumigated fields with and without a th iosulfate amendment.

Most of this data was not available at th e time the fumigant VOC regulations were developed, and DPR is still reviewing the studie s. For the upcoming label changes, U.S. EPA plans to assign a buffer zone credit of 15 percen t when thiosulfate is applied with certain fumigants.

Evaluation of Fumigation Methods – Soil P reparation, Equipment Preparation, and

General Procedures

Fields with large soil clods, debris, or crop residue can exacerbate the channeling effect of

tractor shanks. Labels address proper preparation of fields , so DPR’s regulations do not include any requirements for soil preparation. Si milarly, the labels include requirements for proper equipment calibration and maintenance, as well as prevention of leaks and spills.

Evaluation of Fumigation Methods – Conclusions

Requiring the lowest emission fumigation method is infeasible for several reasons: 1) A single method is not physically possible for all fumigants. For example, methyl bromide is too volatile to apply using chemigation system s, and tractor fumigations are not allowed by the label for sodium tetrathiocarbonate. 2) A single method is not effective in reducing VOC emissions for all fumigants. For example, tracto r injection at deeper de pths reduces emissions for 1,3-dichloropropene, but not methyl bromide. 3) A single method is not effective against all target pests for all crops. For example, chemigation methods are effective against weeds and other pests at shallow depths , but usually ineffective agains t pests at deeper depths. 4) The equipment and other resources are not alwa ys available or very costly, particularly availability of surface water a nd delays due to weather.

It is also infeasible to designate the lowest emission fumigation method for individual combinations of fumigant, crop, pest, and region. This would greatly complicate and lengthen the regulations. Ther e are approximately 50 fumiga nts/fumigant products, 25-60 crops for each fumigant, 4 groups of pests, a nd at least 3 regions, creating several thousand combinations. Many products contain more than one fumigant, particular ly methyl bromide, chloropicrin, and 1,3-dichloropropene. The fumi gation method would need to be specified by product for these fumigants. New fumigant products or changes to labels that add crops or

16pests would require corresponding changes to the regulations. Additionally, specifying a single fumigation method for each of the combin ations would not account for the availability of equipment and other resources.



### Cost of Low-Emission Fumigation Methods

ARB’s Agency-wide Economic Analysis Unit estim ated the direct cost of the fumigant VOC regulations. ARB used the information compile d by DPR in Tables 5a and 5b for the costs associated with the fumigation methods. DPR es timated that the total increased fumigation cost to growers and applicators to comply with the low-emission method requirements was $10 million to $40 million for all NAAs comb ined in 2007, depending on which lowemission fumigation methods gr owers and applicators select ed. Table 2 shows that VOC

emissions reduction attributed to the low-em ission fumigation methods was 3.11 tons/day for all NAAs combined, or 573 tons of total VOCs during May-October. Therefore, the estimated VOC reduction cost was $17,000 to $70,000 per ton, based on prices in 2007. The cost has likely increased since 2007. Secondary ec onomic impacts of the regulations were not considered. Secondary impacts such as loss of jobs to farm labor ers, the increase in bank loan risk, or loss of income to pr ocessors and suppliers, while im portant to the community, do not expressly impact the grower’s profitability and were not included in the economic impact analysis. Direct impacts, such as land valu e losses to growers, we re not considered, as estimating the impact on real estate is uncer tain and highly subject to local influences.



### Other Reduction Options for Pesticide VOC Emissions

The VOC regulations include a fumigant emissi on limit for Ventura un til at least 2012 (3 CCR sections 6452.2 and 6452.3). The regulations also include a trigger for the same system for the other NAAs in the event the reductions from low-emission fumigation methods are insufficient to achieve the SIP goals. Unde r this system, DPR establishes a NAA-wide fumigant emission limit each year by subtrac ting the estimated nonfum igant emissions from the SIP goal. County agricultural commissioners have three options to enforce the fumigant limit: by issuing a fumigant emission allowan ce to each grower who plans to fumigate for the upcoming May-October period; by tracking emissions and denying any permit that would cause the fumigant limit to be treated; or by conditioning permits to further restrict the fumigation methods that can be used. Agricult ural commissioners may implement one or any combination of these three options. Under th e fumigant allowance option, growers in an NAA where a fumigant limit is in effect must request an allowance from the commissioner. Allowance requests must include crop and acres . DPR or the commissioner estimates worstcase emissions by assuming the highest emitting fumigant and method by crop, for all of the requested acreage. The allowa nces are reduced proportionally to bring total fumigant VOC

emissions below the limit for the NAA. Commi ssioners issue the allo wances as a condition of the restricted materials permits. Each grower must manage his/her fumigations by selecting the appropriate combin ation of fumigants, fumigatio n methods, application rates, and number of acres fumigated so the allowance is not exceeded. As restricted materials, growers or applicators must submit a Noti ce of Intent to the county agricultural commissioner for each fumigati on. Commissioners check each Notice of Intent to confirm that it complies with the allowance prior to fumigation. For the Ventura NAA, Table 3 shows

17that the May-October fumigated acreage de creased by 24 percent in the Ventura NAA between 2006-7 and 2008-9 (15,497 acres to 11,833 acres). At least part of this decrease is likely due to the fumigant limit and allowances. (

Prior to implementation of the fumigant regulations in 2008, fumigants contributed 80 percent of more of the pes ticide VOC emissions in the Southeast Desert and Ventura nonattainment areas and more than 40 percent of the emissions in the San Joaquin Valley. DPR implemented regulations for fumigants because their reduction was the only way to ensure the SIP goals were achieved in th e Southeast Desert and Ventura NAAs. These

reductions were also effective for the San Joaquin Valley. However, DPR is working on

other measures to further reduce VOC emissions , particularly for the San Joaquin Valley.

In 1993, U.S. EPA published an alternative control technology document that addresses the control of VOC emissions from the app lication of agricult ural pesticides ( http://www.epa.gov/ttn/naaqs/oz one/ctg_act/199303_voc_epa453_r-92- 011_ag_pesticides.pdf ). To DPR’s knowledge, no other state has measures to reduce pesticide VOC emissions, so there are no othe r evaluations to rely on. The following is DPR’s evaluation of the seven techniques the doc ument identified as technically viable for reducing pesticide VOC emissions:

• Reformulating organic solvent containing pe sticide formulations (e.g., emulsifiable concentrates)

• Reducing fumigant usage

• Using alternative application methods

• Applying microencapsulation techniques

• Using integrated pest management

• Using alternative active ingredients

• Reducing the use of crop oils

Other Reduction Options – Reformulating Organic Solvent Containing Pesticide

Formulations

In 2005, DPR initiated a reevaluation (regulator y process to request actions by pesticide registrants) for several hundred nonfumigant pr oducts. The reevaluation required registrants to submit plans for reformulating the inert ingredients in the products to reduce VOC emissions. DPR stopped work on this reevalua tion and shifted its strategy to reducing emissions with the fumigant regulations. DPR restarted work on nonfumigants in 2010 and

revised the reevaluation to lim it reformulation efforts to th e products with the highest pesticide VOC contribution in the San Joaquin Valley NAA (Figure 4):

• Abamectin products (e.g., Agri-Mek)

• Chlorpyrifos products (e.g., Lorsban)

• Dimethoate products (e.g., Cygon)

• Gibberellins products (e.g., Gibgro)

• Oxyfluorfen products (e.g., Goal)

• Permethrin products

• Trifluralin products (e.g., Treflan)

18See the following web page for more detail ed information on the reevaluation for VOC

emissions from nonfum igant pesticides: http://www.cdpr.ca.gov/docs/emon/voc s/vocproj/req_reformulation_lid.htm

Several registrants began reformulation efforts at the start of the reevaluation, most notably for chlorpyrifos. Products containing chlorpyrifos are the highest or s econd highest pesticide

VOC contributor in the San Joaquin Valley, depending on year (Figure 4). VOC emissions from the inert ingredients in chlorpyrifos products declined 40 percent between 2008 and 2009 in the San Joaquin Valley. This decline was due to a 25 percent decr ease in use, and a 15 percent decrease due to a change in products (Figure 5). DPR registered Lorsban Advanced in July 2008, and its emission potential is 18.45 percent. In contrast, Lorsban 4E, Lorsban 4E-HF, and similar emulisfiable conc entrate products have emission potentials of approximately 50 percent. Many growers and applicators switched from the high-VOC chlorpyrifos products to Lorsban Advanced in 2009. Lorsban Advanced was the highest use chlorpyrifos product in the San Joaquin Valley during 2009 (Table 6).

There are several activities to encourage the voluntary use of low-VOC products. Purchase of low-VOC products is one of three pesticid e VOC measures for which EQIP provides matching funds to growers in California. Under a U.S. EPA grant, DPR prepared a conservation management practices guide fo r pesticide VOCs and developed a companion website for growers and applicators that calc ulates and compares the VOC emissions for pesticide applications.

In conclusion, this measure is feasible becau se several registrants have implemented this measure, and DPR is evaluating possible addi tional regulatory actions for non-fumigant pesticides to require reformulation for certain pesticides. However, it may be infeasible to reformulate some products due to decreased pest control, increased toxicity of the inert ingredients, high cost , or other factors.

Other Reduction Options – Reducing Fumigant Usage

The fumigant regulations include a fumigant limit and allowance system in the Ventura NAA at least until 2012, and as a b ackstop measure in the event low-emission fumigation methods are insufficient to achieve the SIP goals for th e other NAAs. This measure is feasible as a backstop. It requires a reduction in fumigated acr eage, and planting of less profitable crops, or no crops. Additionally it requires a new administrative progra m for DPR, county agricultural commissioners, and the regul ated community. Low-emission fumigation methods are more compatible and less co stly with the current regulatory program.

Other Reduction Options – Using Alternative Application Methods

The alternative control technology document desc ribes this option as “improved-efficiency application equipment.” To encourage the vol untary reduction of emissions, purchase of precision pest control applicati on equipment or “smart sprayers ” is one of three pesticide VOC measures for which EQIP provides matching funds to growers in California. Priority is given to application equipment that uses phot o identification or sona r-type technologies.

19These technologies are primarily used for or chard sprayers, where a sensor controls the amount of spray, and turns off the spray in betwee n trees. This results in less pesticide being applied. This measure is not feasible as a regu latory control because the equipment is costly and the VOC emissions due to pe sticides applied with orchard sprayers are relatively low.

Although not described in the alternative control technology document, the fumigant regulations rely primarily on low-emission fumigation methods to achieve reductions.

Other Reduction Options – Applyi ng Microencapsulation Techniques

This measure consists of reformulating emulsi fiable concentrates into microcapsules to reduce the amount of solvent in the product. DPR has grouped this measure with the reformulation option.

Other Reduction Options – Using Integrated Pest Management

The alternative control technology document desc ribes integrated pest management as an “ecologically based pest management program that combines biological and nonbiological control techniques to suppress weeds, insects, and diseases. This option has been defined as a pest population management system that utiliz es all suitable techniques in a compatible manner to reduce pest populations and main tain them at levels below those causing economic injury.” DPR regulates the use of pesticides, and lacks legal authority to require integrated pest management, which includes non-pesticidal practi ces. However, DPR has programs that encourage the adoption integrat ed pest management, not only to address VOCs, but also to reduce health and envir onmental risks. These programs include DPR’s IPM Innovator awards to honor California orga nizations that emphasize pest prevention, favor least-toxic pest control, and share their successful strate gies with others. DPR has also funded grants and alliances that form a step -wise progression from applied research and demonstration projects to regional or statewide implementation of multi-disciplinary reduced-risk pest management practices. Reducin g VOC emissions is one of the criteria DPR uses to judge applications for pest management grants.

Organic crop production or grow ing crops with no fumigants is possible in some situations, but is infeasible for all crop production. Fo r some annual crops such as strawberries, conventional crops are normally grown every ye ar or every other year on the same field, made possible by soil fumigation. In contrast an organic crop must be rotated with other commodities and are grown on the same field once every several years. There is insufficient

land in California with climate and water to support a conversion to 100 percent organic production. Growing perennial cr ops (orchards, vineyards) can be very risky without fumigants. These crops are subject to infestation by ne matodes and nematode-borne pathogens in preplant/replant situations. In organic vineyards and orchards where soil fumigants are not allowed, the only options are nematode-resistant root stocks and prolonged fallow periods. While nematode-re sistant rootstocks are availabl e for both crops, they are not always a good match for a particular soil type or local climate. The recommended fallow period for grapes is ten years, and this will onl y serve to delay the appearance of nematoderelated symptoms. Nonfumigant pesticides are no t effective against these soil pests after the

20crop is planted. Use of fumigants for some nursery crops is essential. Ma ny fields are planted with seedlings grown in nurseries. To prev ent catastrophic failure in multiple production fields, federal and state laws re quire many nursery crops to be certified as pest-free prior to sales of seedlings. Fumigants are often the only alternative to obt ain the certification.

In conclusion, this measure is not feasible because integrated pest management and organic production are not always technically feasible, and DPR lacks legal authority to implement this as a requirement.

Other Reduction Options – Using Alternative Active Ingredients

This option is not feasible because DPR lacks le gal authority to require certain pesticides to be used. While DPR can regulate or prohibit sa les or use of certain pesticides based on unacceptable risks, DPR cannot require growers a nd applicators to apply specific pesticides in place of the regulated ones.

Other Reduction Options – Reducing the Use of Crop Oils

Crop oils have insecticidal us es, and are among the highest used pesticides in California. (Petroleum oil was ranked sec ond and mineral oil was ranked third in pounds applied during 2009.) However, DPR disagrees that reducing crop oils is a good option to reduce VOC emissions. Based on thermogravimetric analys is data and DPR’s evaluation of 26 oil products, the emission potentials for oil produ cts are low, with a median value of 1.53 percent. Even accounting for the high use, none of the oils are among the top 10 pesticide VOC contributors in any of the NAAs, so a ny reductions would have minimal impact on emissions. Moreover, DPR and others encourage the use of oils because they have lower health and environmental risk in comparison to most other active ingredients in insecticide products, particularly organophosphates. In conclu sion, this measure is not feasible because

the VOC emission reductions associated with this measure are minimal, and will likely cause an increase in use of pesticides with great er health or environmental impact. See the following for DPR’s VOC evaluation of oil products: http://www.cdpr.ca.gov/docs/emon/pubs/e hapreps/analysis_memos/2079_segawa.pdf



### Other issues

Current Research on Fumigant VOC Emission Reduction

Another reevaluation is in progr ess to obtain additional data for current fumigation methods because DPR relied on surrogate data for so me fumigation methods. This reevaluation requested that registrants provide monitoring da ta to confirm the accuracy of the surrogate data. The registrants included CHAIN2D computer modeling of emissions as part of their response. While the registrant modeling was reje cted, DPR started its own efforts to develop a computer model to estimate fumigant emi ssions. Under contract to DPR, the model developer has completed modifications of HYDR US to account for the effect of tarps, bed shape, and other fumigation parameters. Co mparisons of the HYDRUS model to field monitoring data have shown good ag reement in some cases, and disagreement in other cases.

21To assist with validating the model, DPR plans a special field study to gather data that are used for the model inputs, but were lacking in earlier studies. If validated, the model will be used to determine the parameters that affect emissions and guide efforts to reduce emissions.

Numerous researchers are working on methods to reduce fumigant emissions. Much of this work is sponsored by USDA as part of two area-wide programs on methyl bromide alternatives. The Pacific Area-Wide program includes several multi-year projects in California to develop, demonstr ate, and implement fumigant reduction measures. It’s likely

this research will lead to additional low- emission fumigation methods. DPR is currently evaluating data for low permeability tarpaulins from this program. Field monitoring data indicates that low permeability tarpaulins can re duce peak fumigant emissions by as much as 90 percent. However, the data also indicates that relatively high emissions occur at the normal tarp removal time, and the normal tarp removal process may cause unacceptable exposure to workers. Current research is focu sing on the appropriate time period and process to remove low permeability tarpaulins. It may be possible to achieve even greater reductions by using low permeability tarpaulins in combina tion with lower application rates and still effectively manage pests. The Pacific Area- Wide program developed a special a global positioning system (GPS) for tractors that re duces the amount of fumigant needed by 50 percent or more. Intended for orchard and vineya rd applications, tracto rs equipped with this system apply fumigant only at the spot where a tree or vine will be planted. Researchers are working with a major fumigant pest contro l business to modify the GPS system for

commercial use. Research also continues on soil amendments, soil compaction techniques, and other fumigant emission reduction measures . The Pacific Area-Wide program is also conducting research on nonpesticid al alternatives to fumigant s. This includes growing strawberries in soilless substrate, anaer obic soil disinfestation, steam disinfestation, biocontrol agents, and resistant rootstocks. All research of the Pacific Area-Wide program, as well as the Southeast Area-Wide program, and ot her fumigant research are presented at an

annual conference. Information about the resear ch is available at the following conference

website: http://www.mbao.org/

In January 2011, U.S. EPA summarized its eval uation of the available fumigant emissions studies (Attachment 5 – U.S. EPA memorandum from Dawson, Smith, and Shelat to Leahy, dated January 11, 2011). DPR did not use all of st udies used by U.S. EPA because: 1) some studies were not available when the regulati ons were developed in 2007 and are still under review by DPR; 2) some studies were c onducted outside the stat e and do not reflect emissions under California conditions; 3) some studies measured emissions using methods unacceptable to DPR; or 4) some studies we re insufficient to address all DPR exposure concerns. It’s likely that DPR will use the recen t studies to revise the regulations and add new low-emission fumigation methods once the re views are completed and other issues are

addressed.

Time Period of Emission Inventory and Regulations

DPR’s emission inventory and fu migant regulations are based on the peak ozone season of May 1 through October 31 because they implemen t the pesticide element of the 1-hour ozone

SIP. That SIP is based on seasonal inventories. Under that SIP, as approved by U.S. EPA,

22VOC reductions are, and always have bee n, measured over the 6-month ozone season. Likewise the VOC reduction goals of the pestic ide element of that SIP apply, and always have been applied to that time period. The VOC reduction measures of the 1-hour ozone SIP

are seasonal so that the reductions needed during the peak ozone season are required.

Moreover, requiring low-emission fumigation me thods year-round could increase fumigant emissions during the peak ozone season. Fumigant s are applied prior to planting, and are not applied to prevent immediate crop damage. Th erefore, the time window for application is more flexible than most other pesticides . Under the current regulations, growers and applicators have shifted some fumigations ou tside the May-October period to avoid the

additional restrictions. It’s lik ely that these fumigations will shift back to the May-October period if low-emission methods are required ye ar-round. This will result in lower emissions outside the May-October peri od, but greater emissions durin g the May-October period, defeating the overall goal s of the regulations.



### Conclusions

DPR has implemented or is working to impl ement all feasible m easures to reduce VOC emissions from pesticides. DPR has adopted regulations requiring low-emission fumigation methods in certain NAAs, usually consisting of tarping, post-fumigation water treatments, or application through drip irriga tion systems. The VOC regulations also include a fumigant

emission limit for the Ventura NAA at least until 2012. This system is also a backstop measure in the event low-emission fumigation methods are insufficient to achieve the SIP goals for the other NAAs. DPR is working with pesticide registrants to reformulate certain pesticide products that contain high amounts of solvents. DPR and others are conducting

research to further reduce VOC emissions from pesticides. Other measures that would reduce

VOC emissions are infeasible at this time.

23Table 1. Application Method Adjustment Fact or (AMAF) and pesticide use report Field Fumigation Method (FFM) code for each fumigation method.

Regulation

Section Field Fumigation Method FFM Code AMAF (%)

6447.3. Methyl Bromide Fumigation Methods (w ith or without chloropi crin) 1100 series 6447.3(a)(1) Nontarpaulin/Shallow/Bed 1101 100* 6447.3(a)(2) Nontarpaulin/Deep/Broadcast 1102 74* 6447.3(a)(3) Tarpaulin/Shallow/Broadcast – Nobel Plow 1103 48 Tarpaulin/Shallow/Broadcast – Nobel Plow – Strip 1104 74* Tarpaulin/Shallow/Broadcast – Closing shoes and compaction roller 1105 100* 6447.3(a)(4 ) Tarpaulin/Shallow/Bed 1106 100* 6447.3(a)(5) Tarpaulin/Deep/Broadcast 1107 48 Tarpaulin/Deep/Broadcast – Strip 1108 74* 6447.3(a)(6) Drip System - Hot Gas 1109 100*

Other label method** 1190

---

6448.1. 1,3-Dichloropropene Fumigation Methods (with or without chloropicrin) 1200 series 6448.1(c)(1) Nontarpaulin/Shallow/Broadcast or Bed 1201 65* 6448.1(c)(2) Tarpaulin/Shallow/Broadcast 1202 65* Tarpaulin/Shallow/Bed 1203 65* 6448.1(c)(3) Nontarpaulin/Shallow/Broadcast /Three Water Treatments 1204 44 6448.1(c)(4) Tarpaulin/Shallow/Bed/Three Water Treatment 1205 44 6448.1(c)(5) Nontarpaulin/Deep/Broadcast or Bed 1206 26 6448.1(c)(6) Tarpaulin/Deep/Broadcast 1207 26 Tarpaulin/Deep/Bed 1208 26 6448.1(c)(7) Chemigation (Drip System)/Tarpaulin 1209 19

Other label method** 1290

---

6449.1 Chloropicrin-Fu migation Methods 1100-1300

series 6447.3(a)(1) Nontarpaulin/Shallow/Bed 1101 64* 6447.3(a)(2) Nontarpaulin/Deep/Broadcast 1102 64* 6447.3(a)(3) Tarpaulin/Shallow/Broadcast – Nobel Plow 1103 44 Tarpaulin/Shallow/Broadcast – Nobel Plow – Strip 1104 64* Tarpaulin/Shallow/Broadcast – Closing shoes and compaction roller 1105 64* 6447.3(a)(4 ) Tarpaulin/Shallow/Bed 1106 64* 6447.3(a)(5) Tarpaulin/Deep/Broadcast 1107 44 Tarpaulin/Deep/Broadcast – Strip 1108 64* 6447.3(a)(6) Drip System - Hot Gas 1109 100*

6448.1(c)(1) Nontarpaulin/Shallow/Broadcast or Bed 1201 64* 6448.1(c)(2) Tarpaulin/Shallow/Broadcast 1202 44 Tarpaulin/Shallow/Bed 1203 64* 6448.1(c)(3) Nontarpaulin/Shallow/Broadcast /Three Water Treatments 1204 43 6448.1(c)(4) Tarpaulin/Shallow/Bed/Three Water Treatment 1205 43 6448.1(c)(5) Nontarpaulin/Deep/Broadcast or Bed 1206 64* 6448.1(c)(6) Tarpaulin/Deep/Broadcast 1207 44 Tarpaulin/Deep/Bed 1208 44 6448.1(c)(7) Chemigation (Drip System)/Tarpaulin 1209 12

Other label method** 1390

---

24Regulation

Section Field Fumigation Method FFM

Code AMAF (%)

6450.1. Metam-Sodium and Metam-Potassium Fumigation Methods 1400 series 6450.1(d)(1) Sprinkler/Broadcast or Bed/One Water Treatment 1401 77* 6450.1(d)(2) Sprinkler/Broadcast or Bed/Two Water Treatments 1402 28 6450.1(d)(3) Sprinkler/Broadcast or Bed/Three Water Treatments 1403 21 6450.1(d)(4) Nontarpaulin/Shallow/Broadcast or Bed/One Water Treatment 1404 77* 6450.1(d)(5) Nontarpaulin/Shallow/Broadcast or Bed /Two Water Treatments 1405 28 6450.1(d)(6) Nontarpaulin/Shallow/Broadcast or Bed/Three Water Treatments 1406 21 6450.1(d)(7) Chemigation (Drip System) Tarpaulin 1407 9 Chemigation (Drip System) Nontarpaulin 1408 9 6450.1(d)(8) Rotary Tiller 1409 14

Power Mulcher 1410 14

Soil Capping 1411 14 6450.1(d)(9) Flood 1412 77*

6452 Day Drench 1413 100

6452 Night 1A.M. Start/Sprinkler/Broadcast or Bed/Two Water Treatments 1452 77*

6452 Night Nontarpaulin/Shallow/Broadcast or Bed/Two Water Treatments 1455 28

6452 Night 4A.M. Start/sprinkler/Broadcast or Bed/Two Water Treatments 1472 35

Other label method** 1490

---

6450.2. Dazomet Fumigation Methods 1500 series

Soil incorporation 1501 17 Surface application – water incorporation 1502 17

Other label method** 1590

---

6451.1 Sodium Tetrathiocarbonate Fumigation Methods 1600 series Chemigation (Drip) 1601 10 Chemigation (mini-sprinkler) 1602 10 Chemigation (flood, basin) 1603 10 Chemigation (furrow, border) 1604 10 Chemigation (foggers, jets, misters, other) 1605 10

Other label method** 1690

---

6446.1 Methyl Iodide Fumigation Methods 1700 Series Day Tarpaulin/Shallow/Broadcast 1701 100 Day Tarpaulin/Shallow/Bed 1702 100 Day Tarpaulin/Deep/Broadcast 1703 100 Day Chemigation (Drip)/Tarpaulin 1704 100 Day Auger-Probe 1705 100

* Method prohibited within the San Joaqui n Valley, Southeast Desert, and Ventura nonattainment areas during May 1 – October 31. **For use only outside of the May 1 – Oct ober 31 time period; or areas outside of the nonattainment areas; or for exempted applica tions (such as describe d in Sections 6447, 6448, 6449, 6450, and 6451)

25Table 2. Comparison of fumigant emissions and use prior to and after implementation of fumigant VOC regulations (2006-2007 vs . 2008-2009 May-October annual average).

Fumigant VOC Emissions and Use San Joaquin Valley NAA Southeast

Desert NAA Ventura

NAA 2006-7 Fumigant Emissions (tons/day) 6.47 0.49 3.06 2008-9 Fumigant Emissions (tons/day) 3.35 0.092 1.30

2006-7 Fumigant Use (tons/day) 14.39 0.92 8.89 2008-9 Fumigant Use (tons/day) 11.93 0.47 6.53

2006-7 vs. 2008-9 Relative Difference (percent)

Decrease in VOC emissions 48 81 57* Decrease in Amount Applied 17 49 26*

Decrease Due to Low-Emission Methods** 31 32 31

2006-7 vs. 2008-9 Mass Difference (tons/day)

Decrease in VOC emissions 3.12 0.40 1.75*

Decrease Due to Low-Emission Methods** 2.01 0.16 0.95

* Some of the decrease in use for Ventura was due to the fumigant limit and allowances required by the regulations.

** Some of the decrease may be due to cha nges in the procedure for determining the frequency each fumigation method is used.

2627 Table 3. Comparison of fumigant use prior to and after implementation of fumigant VOC regulations (2006-2007 vs. 2008-2009 annual average) . Data is for all fumigants combined.

Fumigant Use San Joaquin Valley NAA Southeast

Desert NAA Ventura

NAA

Amount of Fumigant Used

May-Oct 2006-7 7,005,537 lbs 490,624 lbs 3,283,589 lbs

Jan-Dec 2006-7 16,225,657 lbs 1,029,983 lbs 3,538,332 lbs May-Oct as fraction of 2006-7 43% 48% 93%

May-Oct 2008-9 5,805,199 lbs 317,963 lbs 2,453,000 lbs

Jan-Dec 2008-9 15,710,197 lbs 950,877 lbs 3,018,515 lbs May-Oct as fraction of 2008-9 37% 33% 81%

Size of Area Fumigated

May-Oct 2006-7 49,242 ac 3,456 ac 15,497 ac

Jan-Dec 2006-7 146,872 ac 6,906 ac 16,766 ac May-Oct as fraction of 2006-7 34% 50% 92%

May-Oct 2008-9 40,862 ac 2,332 ac 11,833 ac

Jan-Dec 2008-9 139,861 ac 6,403 ac 14,967 ac May-Oct as fraction of 2008-9 29% 36% 79%

Average Application Rate

May-Oct 2006-7 175 lbs/ac 199 lbs/ac 216 lbs/ac Jan-Apr & Nov-Dec 2006-7 164 lbs/ac 190 lbs/ac 241 lbs/ac

May-Oct 2008-9 167 lbs/ac 205 lbs/ac 291 lbs/ac Jan-Apr & Nov-Dec 2008-9 167 lbs/ac 189 lbs/ac 199 lbs/acTable 4. Summary of the evaluation ofpossible fumigation method restrictions.Possible Restriction1,3-DichloropropeneChloropicrinMethyl BromideMethyl IodideMITCSodiumTetrathiocarbonateIntroduction - DripLow-emissionLow-emissionNot allowed by labelsLow-emissionLow-emissionLow-emissionIntroduction - OtherChemigationNot allowed by labelsNot allowed bylabelsNot allowed by labelsNot allowed bylabelsSeveral methodsallowed, additionalrequirements forlow-emissionSeveral methodsallowed, all lowemissionIntroduction -Tractor ShankSeveral methodsallowed, deep shankis low-emissionSeveral methodsallowed, additionalrequirements forlow-emissionSeveral methodsallowed, additionalrequirements for lowemissionSeveral methodsallowed, additionalrequirements forlow-emissionSeveral methodsallowed, additionalrequirements forlow-emissionNot allowed by labelTarpingIneffectiveLow-emissionmethodLow-emissionmethodHighly retentivetarp low-emissionNot testedIncompatible withchemigationSoil MoistureRegs superseded bylabelsRegs supersededby labelsRegs superseded bylabelsLabel requirementRegs supersededby labelsRegs superseded bylabelWater Treatments3 or more for low-emission3 or more for low-emissionNot testedNot tested2 or more for low-emissionLabel requirementsApplication RateMax based on highestrate testedMax based onhighest rate testedMax based on highestrate testedMax based onhighest rate testedMax based onhighest rate testedMax based on highestrate testedWeather RestrictionsInsufficient dataInsufficient dataLittle or no effect onemissionsInsufficient dataInsufficient dataInsufficient dataSoil CharacteristicsInsufficient dataInsufficient dataLittle or no effect onemissionsInsufficient dataInsufficient dataInsufficient dataSoil AmendmentsVariable results,possible odorVariable results,possible odorVariable results,possible odorNot testedNot testedNot testedSoil and EquipmentPrepLabel requirementsLabel requirementsLabel requirementsLabel requirementsLabel requirementsLabel requirements28Table 5a. Standard fumigation costs in 2007.

Fumigant $/lb. Active Ingredient Per acre costs**

Methyl Bromide $3.50 $2100 (350 lbs/ac, br oadcast shank injection, tarped Chloropicrin $3.00 $1400 (200lb/ac, broa dcast shank injection, tarped)
1,3-D tractor $1.40 $550 (35 gal/ac, broa dcast shank injection, untarped) 1,3-D drip $2.40 $640 (25 gal/ac, drip application)

Metam Sodium $1.00 $400 (75 gal/ac, shank injection, water seal)

* Tom Trout, USDA-ARS, Fumigant use trends in California; Response to MeBr PhaseOut.

Annual International Research Conference on Me thyl Bromide Alternatives and Emissions Reductions, 2006. **Includes both fumigant and application costs

Table 5b. Costs of conversion to lo w-emission fumigation methods in 2007.

Fumigant application

method Fumigant Increased $/ac* Acres (average 2003-2005)* Estimated total cost

of conversion

SJV = 124,750 $63,622,500

SE Desert = 4,280 $2,182,800 Convert to drip application from shank injection (drip system already in place)* 1,3-dichloropropene Chloropicrin

Metam $510 1

Ventura = 6,408 $3,268,080
SJV= 124,750 $313,122,500
SE Desert = 4,280 $10,742,800 Convert to drip application from shank injection (including installation of drip system)** 1,3-dichloropropene Chloropicrin

Metam $2510 2

Ventura = 6,408 $16,084,080

SJV= 124,750 $1,247,500
SE Desert = 4,280 $42,800 Post-application water treatments (sprinkler system already in place)** 1,3-dichloropropene Chloropicrin

Metam $10 3

Ventura = 6,408 $64,080

SJV= 124,750 $29,940,000

SE Desert = 4,280 $1,027,200 Post-application water treatments (including rental of sprinkler system** 1,3-dichloropropene Chloropicrin

Metam $240 4

Ventura = 6,408 $1,537,920

SJV= 16,898 $6,759,200

SE Desert = 30 $12,000 Tarping – methyl bromide Trees & Vines Only ** Methyl Bromide $400 5

Ventura = 32 $12,800 * Increased costs per acre: Tom Trout, USDA- ARS, Fumigant use trends in California; Response to MeBr PhaseOut. Annual Internati onal Research Conference on Methyl Bromide Alternatives and Emissions Reductions, 2006. ** Increased cost per acre estimates provided by Husein Ajwa, Ext Specialist, UC Davis Dept. of Plant Sciences, Salinas, CA +1 831 755 2823.

1 Materials and installation costs: tarp + drip tape = $5 00, water = $10 for 3 x 1⁄4 inch applications within two days after fumigation

2 Materials and installation costs: tarp + drip ta pe $500, water = $10, Install drip system $2000

3 Water: $10/ac in. for 3 x 1⁄4 inch appli cations within two days after fumigation

4 Sprinkler rental = $200 and setup = $40; (purchase sprinklers about $2000/ac).

5 Tarp and application = $400

29Table 6. Use of major chlorpyrifos products and liquid low-VOC alternatives in the San Joaquin Valley NAA.

Product Use May-Oct (lbs) Product Emission Potential (%) 2008 2009

Nufos 4E 52.30 176,922 190,975

Lorsban 4E 50.00 500,314 188,032

Govern 4E 50.00 185,234 141,313

Lorsban 4E-HF 48.68 423,639 116,953

Lorsban Advanced 18.45 2,323 386,662

Lock-On 20.90 305,620 176,505

30Figure 1. Nonattainment areas included in the pesticide element of the ozone state implementation plan.

CALIFORNIA CALIFORNIA

Sacramento

Metro

San Joaquin Valley

Southeast

Desert

South Coast

Ventura * Sacramento Metro NAA - all of Sacramento and Yolo counties, and parts of El Dorado, Placer, Solano and Sutter counties.

* San Joaquin Valley NAA - all of San Joaquin, Stanislaus, Merced, Madera, Fresno, Kings, and Tulare counties, and the valley portion of Kern County.

* South Coast NAA - all of Orange County, and part of Los Angeles,

Riverside and San Bernardino counties.

* Southeast Desert NAA - the desert portions of Riverside (Coachella Valley), Los Angeles (Lancaster/Palmdale), and San Bernardino (Barstow) counties.

* Ventura NAA - all of Ventura County. 

# ® FEDERAL NON-ATTAINMENT AREAS
AFFECTED BY CALIFORNIA REGULATIONS
TO REDUCE EMISSIONS
FROM
FUMIGANT PESTICIDES

January 2008

31Figure 2. Pesticide VOC emission inventory for 1990-2009. The emissions using fumigant Application Method Adjustment Factors canno t be calculated for 1991-2004 due to lack of data on the frequency each fumigation me thod was used (method use fractions).

NAA 1 Sacramento Metropolitan

Year 1 9 9 0 1 9 9 5 2 0 0 0 2 0 0 5 2 0

1 0 2 0

1 5Emission Rate (tpd)

0.0 0.5 1.0 1.5 2.0 2.5 3.0 NAA 2 San Joaquin Valley

Year 1 9 9 0 1 9 9 5 2 0 0 0 2 0 0 5 2 0

1 0 2 0

1 5Emission Rate (tpd)

0 5 10 15 20 25

NAA 3 Southeast Desert

Year 1 9 9 0 1 9 9 5 2 0 0 0 2 0 0 5 2 0

1 0 2 0

1 5Emission Rate (tpd)

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 NAA 4 Ventura

Year 1 9 9 0 1 9 9 5 2 0 0 0 2 0 0 5 2 0

1 0 2 0

1 5Emission Rate (tpd)

0 1 2 3 4 5

NAA 5 South Coast

Year 1 9 9 0 1 9 9 5 2 0 0 0 2 0 0 5 2 0

1 0 2 0

1 5Emission Rate (tpd)

0 2 4 6 8 10 12



## • Adjusted Emissions

(1990, 2004, 2005, 2006, 2007, 2008 & 2009)

SIP Goals

32Figure 3. Statewide use offield fumigants.05,000,00010,000,00015,000,00020,000,0001988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

Statewide Use (lbs)1,3-DChloropicrinMethyl BromideMITC pesticidesSodium Tetrathiocarbonate33Figure 4. VOC emissions from pesticide produc ts used in the San Joaquin Valley during May-October 2009, by active ingredient. Emissi ons from glyphosate products are likely overestimated due to the lack thermogravimetri c analysis data for one high-use product and the assignment of a high default emission potential.

1,3-D

9%

Glyphosate

8%

Glufosinate

3% Methyl bromide

2% Dimethoate

4% Abamectin

5% Gibberellins

5% Oxyfluorfen

5% Metam

11%

Acrolein

2% Fenpyroximate

2% Trifluralin

2% All other pesticides

32% Chlorpyrifos

10%

34Figure 5. Chlorpyrifos use and product VOC emissions in the San Joaquin Valley during May-October.



### 0 250,000 500,000 750,000 1,000,000

Active ingredient VOC emissionsAmount (lbs)



## 2008 2009

35