## Air Resou^rces Board

Mary D. Nichols, Chairman 1001 I Street • P.O. Box 2815 Sacramento, California 95812 • www.arb.ca.gov ,% .^ 

# ^

Matthew Rodriquez Secretary for Environmental Protection ^_ :.^.. . 

## ^..

Edmund G. Brown Jr. Govemor

June 26, 2013

m 

### N O

"' ^

^ ^' T ^ r _ ^ ^ ^---^ Mr. Robert Perciasepe ^ Acting Administrator ;; ; ^ `" ^ U.S. Environmental Protection Agency ^ ^' ; ^_ EPA Docket Center, Air and Radiation Docket, Mail Code 2822T ^^^

_ 1200 Pennsylvania Avenue NW ^ ;^- Washington, DC 20460 iD Attention Docket ID No. EPA-HQ-OAR-2011-0135

Re: The California Air Resources Board's Comments on the U.S. Environmental Protection Agency's Control of Air Pollution from New Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards (Federal Register Vol. 78, No. 98, pp. 29816-30191)

Dear Acting Administrator Perciasepe:

The California Air Resources Board (CARB) appreciates the opportunity to provide comments on the recently published Notice of Public Rulemaking for the U.S. Environmental Protection Agency (U.S. EPA) Motor Vehicle Emission and Fuel Standards Tier 3 program. CARB strongly supports the Tier 3 program as proposed and offers our comments to the program in the attachment to this letter. We believe the program as proposed represents a noteworthy strengthening of the current Tier 2 program and will achieve significant criteria emission reductions from the national passenger vehicle fleet.

Our comments on the Tier 3 proposal are divided into nine areas:

• The proposed Tier 3 exhaust emission requirements; • The proposed Tier 3 evaporative emission and On-Board Refueling Vapor requirements; • The proposed Tier 3 particulate matter standards and test procedures; • The proposed Tier 3 On-Board Diagnostic requirements; • The proposed Tier 3 In-Use Verification program; • The Tier 3 fuel standards; • The Tier 3 certification test fuel specifications; • The economic benefits of Tier 3; and • The proposed test methods for unregulated and special pollutants.

The energy challenge facing California is real. Every Califomian needs to take immediate action to reduce energy consumption. For a list of simple ways you can reduce demand and cut your energy costs. see our website: http://www.arb.ca.gov

.

California Environmental Protection Agency

Printed on Recycled Paper^ 3

Mr. Robert Perciasepe June 26, 2013 Page 2

CARB shares U.S. EPA's goal of reducing vehicle emissions to improve air quality. Despite significant progress in reducing smog-forming and particulate matter emissions from the passenger vehicle fleet, California needs further reductions in order to meet state and federal ambient air quality standards. To help achieve these standards, CARB adopted the Low-Emission Vehicle (LEV III) regulations last year as part of our Advanced Clean Cars program. The Advanced Clean Cars program combines the control of smog-causing pollutants and greenhouse gas emissions into a single coordinated package of requirements for model years 2015 through 2025 and assures the development of environmentally superior cars that will continue to deliver the performance, utility, and safety vehicle owners have come to expect.

CARB is mindful of the cooperative effort between CARB and U.S. EPA in the development of the new vehicle exhaust emission standards for California's LEV III program and the federal Tier 3 program. It is our intent to evaluate the Tier 3 rule once it is finalized to determine where it is appropriate to further align the LEV III regulation with the federal rule, without sacrificing the stringency and emission benefits of the LEV III program. Since any delay in finalizing Tier 3 would potentially impact the implementation date of this important program, CARB urges U.S. EPA to proceed expeditiously to finalize the program before the end of this year. We also look forward to continue working with U.S. EPA in an attempt to resolve any remaining differences between the two programs after the Tier 3 regulations are finalized.

Our primary goal continues to be improving air quality in California. To this end, California has a separate and unique Zero-Emission Vehicle Program, which we will continue to pursue in order to ensure the prompt and successful deployment of advanced technology zero-emission vehicles. Accordingly, any determination of the extent to which it would be appropriate for California to incorporate elements of the Tier 3 program into our light-duty vehicle program would need to take into consideration our ability to sustain progress towards California's long term plans for transforming the vehicle fleet for reduction of criteria pollutants. In addition, any modifications to the LEV III program must be structured to assure that the emission reductions provided by the California program will be maintained.

If you need additional technical information on our comments, please contact Ms. Annette Hebert, Chief of our Mobile Source Control Division, at (626) 575-6807.

Sincer ly,

. s y, 'L G 

### ^j ^ Ma D. ichots ^^ Chai

Attachment

cc: See next page.# ^ ^

Mr. Robert Perciasepe

June 26, 2013 Page 3

cc: Mr. William Charmley Acting Director U.S. Environmental Protection Agency Assessment and Standards Division 2000 Traverwood Drive Ann Arbor, MI 48105

Mr. Richard W. Corey Executive Officer

Dr. Alberto Ayala Deputy Executive Officer

Mr. Aron Livingston Assistant Chief Counsel Office of Legal Affairs

Dr. Michael Benjamin, Chief Monitoring and Laboratory Division

Ms. Annette Hebert, Chief Mobile Source Control Division

Ms. Cynthia Marvin, Chief Stationary Source Division;^" ^ ^.Page 1



### ^^i_is^.il^^t1_1►^

California Air Resources Board's Comments on the Proposed Tier 3 Rulemaking

Comments on Proposed Tier 3 Exhaust Emission Requirements

The California Air Resources Board (CARB) is fully supportive of the proposed Tier 3 federal test procedure (FTP) and supplemental federal test procedure (SFTP)requirements. With a few exceptions, the proposed requirements mirror the LowEmission Vehicle (LEV III) requirements effectively addressing manufacturers' concerns regarding compliance with both national and California emission programs. In order to further harmonize program requirements of both agencies, CARB intends to align the LEV III rule with a number of the Tier 3 FTP and SFTP requirements after Tier 3 is finalized as noted below and offers the following comments on the proposal.

Tier 3 Federal Test Procedure Requirements

Comment 1— Small Volume Manufacturer Provisions

California has traditionally provided relief to Small Volume Manufacturers (SVM) (primarily producers of high performance vehicles), recognizing that they are at a competitive disadvantage with larger manufacturers in terms of both investment and engineering resources. In addition, they must compete with full line manufacturers who are able to offset the emissions of their low volume high performance vehicles with higher volume, lower emission vehicles. For these reasons, LEV III provides slightly less stringent emission standards for SVMs.

Unlike LEV III, Tier 3 requires SVMs to defer compliance with the Tier 3 fleet average standards until 2022. The Notice of Proposed Rulemaking (NPRM) requests comment on this and an alternative requirement that matches LEV III requirements through 2024 and then requires that SVMs meet Tier 3 fleet average requirements in 2025. Since harmonization of SVM requirements will allow these manufacturers to certify the same vehicle to both programs, CARB recommends that U.S. EPA consider finalizing the alternative requirement by matching Tier 3 requirements with LEV III through 2024. Since Tier 3 allows SVMs to apply for hardship relief under certain conditions, thereby addressing their concerns on competing with full line manufacturers, CARB will review the Tier 3 SVM requirements when finalized and determine whether alignment between LEV III and Tier 3 requirements for SVMs beginning in 2025 is appropriate.

Independent operational manufacturers are a subset of small volume manufacturers. These manufacturers would qualify for small volume manufacturer status, except theyPage 2

are owned by a larger manufacturer and their sales are currently aggregated with the larger manufacturer when determining emission compliance. Both the California and federal greenhouse gas programs allow these manufacturers to meet small volume manufacturer emission requirements if they can demonstrate that they operate completely independently from the owner manufacturer (design and manufacture of powertrains, receive no fiscal support from owner manufacturer, etc.). The LEV III program extends SVM status to these manufacturers for criteria emission requirements and CARB recommends that this manufacturer category be included in the Tier 3 program.

Comment 2— Medium-Duty Vehicle Fleet Average Requirement

Unlike the LEV III program that requires manufacturers to certify a defined percentage of their medium-duty vehicles to increasingly stringent emission standards, the proposed Tier 3 program imposes a fleet average emission requirement for this class of vehicles. Staff has determined that, while different in structure, the LEV III and proposed Tier 3 emission requirements for medium-duty vehicles are identical. Accordingly, to provide manufacturers with additional flexibility, CARB will propose an identical fleet average option for compliance in the LEV III program.Page 3

Tier 3 Supplemental Federal Test Procedure Requirements

Comment 1- SFTP Enrichment Limitation Requirement

CARB supports U.S. EPA's Tier 3 proposal to reduce the tolerance of additional enrichment from six to four percent of the air to fuel ratio of Lean Best Torque. CARB believes the reduced tolerance is appropriate and feasible due to the improved fuel control utilized by today's vehicles. CARB intends to propose alignment with this proposal once the Tier 3 program is finalized.

Comment 2- SFTP Light-Duty Vehicle Interim In-Use Emission Standards

CARB supports U.S. EPA's proposal to not include relaxed interim emission standardsfor non-methane organic gas (NMOG) + oxides of nitrogen (NOx) and (PM) in the lightduty SFTP program. CARB agrees that the technologies required for the proposed SFTP emission standards are well-established .and interim emission standards, typically reserved for new technologies, are not need^d. Accordingly, CARB intends to propose alignment with this proposal once the Tier 3 program is finalized.

Comment 3- SFTP Test Requirements for Fuel-Flexible Vehicles

CARB supports U.S. EPA's Tier 3 proposal to require fuel-flexible vehicles to certify to SFTP standards using both gasoline fuel and the highest ethanol content fuel that a given vehicle is designed to operate on. CARB believes this proposed requirement would ensure that emissions are controlled with all possible fuel blends and will propose inclusion of this provision in the LEV III program once the Tier 3 program is finalized.

Comment 4— Linking of Medium-Duty Vehicle FTP and SFTP Emission Standards

CARB supports the proposal to require medium-duty vehicles certifying to a Tier 3 ultralow-emission vehicle or super-ultra-low-emission vehicle FTP-equivalent emission category to certify to the equivalent SFTP emission category as well. CARB believes this requirement is appropriate because the SFTP emission standards were designed to be met using the same hardware required to meet the FTP emission standards. Accordingly, CARB intends to propose alignment with this proposal once the Tier 3 program is finalized.

Comment 5- SFTP Medium-Duty Vehicle Interim In-Use Emission Standards

CARB supports U.S. EPA's proposal to not include interim in-use emission standards for NMOG+NOx and PM in the medium-duty vehicle SFTP program. CARB agrees that the technologies required for SFTP compliance are well-established and sufficient lead time is provided such that in-use interim emission standards, which are typicallyPage 4

reserved for new technologies, are not needed. Accordingly, CARB intends to propose alignment with this proposal once the Tier 3 program is finalized.

Comment 6- SFTP Light-Duty NMOG+NOx Certification Options

The LEV III program sets forth a separate option for certifying light-duty vehicles to the SFTP NMOG+NOx standards, primarily to accommodate small volume manufacturers. While the proposed Tier 3 program does not include an equivalent option, alignment between the two programs is not necessary because Tier 3 would accommodate small volume manufacturers through a different mechanism. Specifically, Tier 3 would delay SFTP compliance for small volume manufacturers until model year 2022. Accordingly, CARB does not intend to propose any changes to the LEV III program for this issue.Page 5



### Comments on Proposed Tier 3 Evaporative Emissions and On-Board

Refueling Vapor Recovery Requirements

Comment 1- RVP 10 fuel implications for evaporative emission testing

The NPRM requests comment for alternatively requiring E10 with Reid Vapor Pressure (RVP) of 10 psi rather than E15 with an RVP of 9 psi for certification emissions testing. Regardless of which fuel U.S. EPA finalizes for Tier 3, CARB strongly recommends that U.S. EPA maintain an equivalent level of stringency for evaporative emission testing with LEV III evaporative emission standards. If equivalency between Tier 3 and LEV III evaporative requirements is maintained, CARB intends to accept test data from vehicles tested using Tier 3 certification fuel and temperatures to meet the LEV III evaporative emission requirements. See also our more detailed comments on Tier 3 certification fuel on pages 21-22 of this document.

Comment 2- Evaporative leak test

CARB supports the proposed evaporative leak test and standard, and believes that the leak test program will be effective in reducing in-use evaporative emissions. Accordingly, CARB intends to propose alignment with this proposal once the Tier 3 program is finalized.

Comment 3- Evaporative canister bleed test standard in-use requirement

CARB supports U.S. EPA's proposal to implement an in-use requirement for the bleed test standard. This in-use requirement would ensure that canister performance is maintained as vehicles age. Accordingly, CARB intends to propose alignment with this proposal once the Tier 3 program is finalized.

Comment 4- Evaporative emission standards specifically for when an auxiliary (non-road) engine is installed in a motor vehicle

CARB supports U.S. EPA's proposal to extend evaporative emission requirements to auxiliary non-road engines installed on motor vehicles. This would provide additional control of evaporative emissions. Accordingly, CARB intends to propose alignment with this proposal once the Tier 3 program is finalized.

Comment 5- Evaporative emission requirements for alternative fuels

The NPRM requests comment on whether the evaporative emission requirements should be modified in Tier 3 so that the standards only apply to volatile liquid fuels, which would effectively remove evaporative emission requirements for liquefiedPage 6

petroleum gas and natural gas. CARB recommends that U.S. EPA retain the current applicability of the evaporative requirements by continuing to require that liquefied petroleum gas and liquefied natural gas vehicles certify to evaporative emission standards. CARB currently has an evaporative emission requirement for liquefied petroleum gas vehicles. Although existing California evaporative control regulations do not specifically include liquefied natural gas, we believe controlling evaporative emissions from liquefied natural gas systems is warranted and intend to pursue such action in the future. Having an evaporative emission requirement for these vehicles assures that system venting does not occur during normal diurnat conditions, and that other sources of evaporative emissions are controlled.

Comment 6- Evaporative emission testing spare tire removal allowance

The proposed Tier 3 regulatory language (§1066.814) contains an allowance to remove the spare tire during evaporative emission testing. This provision conflicts with the text in the NPRM that only allows exchanging the vehicle's spare tire with one that has been aged. CARB supports the proposed allowance to exchange the spare tire with an aged one, but does not agree with allowing spare tire removal. Such an allowance would reduce the stringency of the whole vehicle emission standards, which aiready account for background emissions, inciuding those from the spare tire.

Comment 7- Evaporative certification method for heavy-duty vehicles over 14,000 Ibs. Gross Vehicle Weight Rating

The NPRM requests comment on a proposal to modify existing certification requirements for heavy-duty vehicles over 14,000 Ibs. gross vehicle weight rating so that evaporative certifications would rely soleiy on design parameters and engineering analysis instead of emissions testing. LEV III test procedures require engineering analysis and data to certify vehicles in this weight category for evaporative emissions, but do not specifically preclude emission testing as U.S. EPA is suggesting. Because some auto manufacturers may prefer to do actual testing, CARB recommends that Tier 3 include actual testing as a means of ineeting the evaporative emission requirement. Nonetheless, CARB anticipates providing reciprocity to federal evaporative emission certification for these vehicles once Tier 3 is finalized.

Comment 8- Evaporative emission testing reduced canister loading allowance for pressurized fuel systems

The NPRM requests comment on allowing reduced canister loading for a pressurized system. This load procedure would be proposed by the auto manufacturer to reflect actual diurnal canister loading using the manufacturer's specific technology. CARB is concerned that this would reduce the stringency of the test and may result in future vehicles that have inadequate ability to purge the canister. The current requirement toPage 7

load a canister to breakthrough is a critical part of the evaporative emission test, which ensures that enough purge capability is designed into the vehicle to purge a full canister during an 11-mile FTP drive cycle. While CARB recognizes that certain engine technologies in the future will have reduced purge capabilities, there are already a number of strategies available today that could help compensate, such as heated purge, optimization of purge strategy to maximize use of available engine vacuum, and purge pumps. Accordingly, CARB recommends that the canister loading procedure remain as proposed.

Comment 9- Refueling: Modifying the terms for exemption from the refueling requirement for diesel vehicles

CARB does not support U.S. EPA's proposal to withdraw the condition that the fuel tank temperature not exceed 130°F in order for a diesel vehicle to qualify for an exemption from the refueling emission requirement absent data showing there would be no emission impact. Accordingly, the NPRM should cite any studies supporting such an action. While less volatile than gasoline, diesel fuel will still generate vapors; especially under higher temperatures. If the original reguaatory language is retained, it would likely act to encour,age auto manufacturers to consader heat exposure when designing and locating the fuel tank, which would result in reduced refueling emissions.

Comment 10 - Evaporative option to use design based certification on gaseousfueled vehicles

Subsequent to adopting evaporative emission standards for gaseous-fueled vehicles, U.S. EPA developed designed-based certification procedures for other sources (i.e., for marine vessels pursuant to 40 Code of Federal Regulation (CFR) 1060.240). These designed-based certification procedures would minimize or eliminate certification emission testing. The NPRM requests comment on changing the certification requirements for gaseous-fueled vehicles to a design-based approach, which U.S. EPA contends would allow for a simpler assessment when certifying these vehicles. CARB does not support this approach and believes that testing vehicles is still the most effective way to-ensure system integrity and evaporative emission control. Whole vehicle testing also ensures that the evaporative system as installed in the vehicle, rather than its individual components, is properly evaluated such that the evaporative emission targets are met.Page 8



### Comments on Proposed Tier 3 PM Emission Standards and Test Procedures

CARB supports the Tier 3 PM standards proposed by U.S. EPA through the 2024 model year. These standards, when fully implemented in 2022, represent a 70 percent reduction from current PM standards and will ensure new vehicles and technologies will continue to perform at levels achieved by the best of today's vehicle technologies. We also agree with U.S. EPA that these standards are readily achievable with no additional technology or hardware.

However, the federal program does not include the LEV III 1 milligram per mile (mg/mi) PM standard that phases-in between model years 2025-2028, stating "In order for U.S. EPA to propose a standard at this level, there must be established methods to reliably and consistently measure PM below that standard, for compliance purposes." While we understand U.S. EPA's reluctance at this time due to concerns with current and proposed test methods, we encourage U.S. EPA to consider adoption of such a standard as discussed below. CARB is in the process of completing testing studies, which will show that existing methods can be modified in a straightforward manner to achieve accurate and repeatable measurement of sub-1 mg/mi PM emissions. At the same time, CARB is also pursuing additional research to explore alternative methods for PM measurement in order to take advantage of promising, new commercially available real-time instruments. We also urge U.S. EPA to re-examine the proposed PM standards for the SFTP for the reasons discussed below.

CARB adopted the 1 mg/mi PM standard because PM emissions are a particular concern for their multiple impacts on public health, air quality, and the global climate. In general, mobile sources (mainly cars and trucks) are not major contributors to the statewide total PM mass inventory. For instance, the PM emissions from light-duty vehicles add up to less than 5 percent of the total California PM 2 5 inventory. However, they do contribute significantly to urban pollution and human exposure, such as the elevated concentrations of PM near heavily-travelled roadways. Historically, PM emissions from diesel engines were of most concern because of their high PM emission rates relative to gasoline engines. But as the modern diesel engine achieves increasingly lower PM emissions, the interest in and relative contribution of PM emissions from an ever increasing number of gasoline-fueled light-duty vehicles is growing. Thus, the need for maximum mitigation of PM emissions at the source (i.e., tailpipe) using the most technically and economically feasible approach is paramount.

We have 4 specific comments regarding the PM emissions standards and test procedures proposed in the Tier 3 NPRM and the draft Regulatory Impact Analysis. The comments are:Page 9

Comment 1- Harmonization of 1 mg/mi PM standard between Tier 3 and LEV III

As stated above, based on studies CARB and others have conducted recently, we believe the measurement method will not be an issue for implementing a 1 mg/mi PM standard for the 2025 model year or sooner. We agree with U.S. EPA on the statement that meeting the 1 mg/mi PM standard requires establishing methods to reliably and consistently measure PM below the standard. CARB, U.S. EPA, and some industry laboratories have already measured and reported PM emissions from light-duty vehicles well below 1 mg/mi using the existing three filter method prescribed by 40 CFR Part 1065. In its draft Regulatory Impact Analysis, U.S. EPA reported FTP composite PM emission results for 16 light-duty passenger cars and trucks (Table 1-8 of the Regulatory Impact Analysis}. Reported PM emissions from 11 of the 13 conventional port fuel injection vehicles were below 1 mg/mi, ranging from 0.10 to 0.93 mg/mi. With the exception of a few repeat results with carriparatively high variability, the data in Figure 1-8 of the Regulatory Impact Analysis suggests reasonably good precision and repeatability in the vast majority of the tests. 7he reason for the high variability in a few results needs investigation, but may be attributed to vehicle stability. Reproducibility between different tests cells and/or laboratories also needs to be addressed so that consistent results for certification and compliance can be generated within acceptable margins.

CARB has already developed and implemerited a strict laboratory filter handling and weighing procedure (MLD 145'} that minimizes variability from the filter weighing contribution of PM measurement. The background contribution from the Constant Volume Sampler dilution tunnel at CARB facilities has been determined to be no more than 2.5 micrograms per filter. The proposed test method in 40 CFR Part 1066 allows for a maximum'background correction of 5 micrograms per filter, which is equivalent to 0.20 mg/mi PM with nominal Constant Volume Sampler flow of 350 standard cubic feet per minute and na secondary dilution. Allowance for the correction subtracts most or all of the system's contribution to a PM measurement. Therefore, manufacturers can design closer to the standard and still have a reasonable probability of passing a one test certification requirement.

CARB also agrees with U.S. EPA's proposed test procedure changes that will allow the use of fewer filters when conducting PM measurements. Conceptually, this will reduce measurement variability as well as the test burden associated with weighing multiple filters. CARB is evaluating the various filter options proposed in 40 CFR Part 1066 and develop defined filter test method procedures. We expect the additional options will show even further improvement in the capability of the gravimetric technique for measurement of PM below 1 mg/mi.

^ CARB SOP NO. MLD145: PROCEDURE FOR THE DETERMINATION OF PARTICULATE MATTER (PM) MASS COLLECTED ON FILTERS. http:l/www.arb.ca.gov/testmeth/slb/sop145v5 1.pdfPage 10

Given the progress to date and ongoing work, CARB anticipates that improved test procedures, in conjunction with the implementation of strict laboratory filter handing and weighing procedures, will allow consistent and reliable gravimetric PM measurement well below 1 mg/mi. CARB believes that the automotive industry can make the necessary changes to their emission certification laboratories in a timeframe that allows for an earlier implementation of the adopted 1 mg/mi standard than the 2025 model year. To that point, CARB recommends that U.S. EPA consider adoption of a 1 mg/mi PM standard to be consistent with the standards CARB adopted in the LEV III regulations, and commit to evaluate in the near future, concurrently with CARB, whether the standard could be implemented even earlier than the scheduled 2025 model year start date.

Comment 2- Further evaluation of proposed filter options is needed and demonstration of the equivalence among the proposed filter options is critical to reduce lab to lab variability '

The NPRM requests comment on alternative approaches to sampling of PM emissions. Specifically, allowing the use of one or two filters during the Urban Dynamometer Driving Schedule. Accordingly, the proposed ±est procedures in CFR Part 1066 allow the use of fewer filters when conducting PM measurements. As noted above, conceptually, the use of fewer filters per test should reduce measurement variability and test burden. However, using fewer filters, particularly the one filter option, rnay have undesirable adverse impacts for collecting PM mass on filter media. For example, in order to comply with the weighting factors specified in the CFR for determining PM mass emissions, filter face velocity in the single filter option has to be lowered during the cold-start and hot-start phases of the FTP cycle. Lowering the filter face velocity could lead to lower PM mass collection on the single filter. Because PN1 emissions are the highest during the cold-start phase of the FTP cycle for most internal combustion engines, this could end up significantly impacting PM mass collection.

In addition, a longer sampling time on a single filter, when compared with the conventional three filter method, could impact the adsorption and desorption equilibrium of semi-volatile organic compounds captured on filter media. Longer sampling times might cause either a gain or loss of filter sample mass by adsorbing or stripping away organic compounds. The effect of this process could lead to higher variability, especially higher lab to lab variability if different filter sampling metl^ods are used.Further, if the PM emitted from a vehicle is comprised mainly of volatile and semivolatile organic compounds, the effect could be more unpredictable.

Establishing correlation arnong the proposed filter options in 40 CFR Part 1066 is essential to ensure repeatability and repr-oducibility for vehicle certification and compliance testing. Currently there is very limited data avaiiable for evaluating the correlation and variability among the proposed fiiter options, especially the single filterPage 11

method. Therefore, the proposed filter sampling options need to be fully evaluated and correlation criteria need to be established. This is important for reducing lab to lab variability for the 3 mg/mi standard, and even more critical for the success of implementing the California ^EV III 1 mg/mi PM standard. CARB is committed to working with U.S. EPA in conducting a comprehensive evaluation of the proposed filter methods, especially the one filter method, to determine the most appropriate method for measuring P.M emissions at 1 mglmi levels.

Comment 3- Set lower PM standards Over the Supplemental Federal Test Procedure — US06 Cycle

The proposed Tier 3 program includes US06 PM standards of 10 mg/mi for lighter vehicles and 20 mg/mi for heavier vehicles. E3ased on recent PM emission data generated by both CARB and U.S. EPA test programs, CARB believes that a more stringent US06 PM standard of 4 mg/mi applicable to both vehicle categories is feasible. The following is a summary of these test programs as well as CARB's rationale for the recommendation.

Prior to California's LEV III rulemaking, eight California LEV II-certified light-duty vehicles, which included five gasoline direct injection vehicles and three port fuel injection vehicles, were tested for PM emissions over the US06 cycle in CARB's Naagen-Smit laboratory. Measured PM emissions from seven out of eight vehicles were below 3 mg/mi, including all five gasoline direct injection vehicles. A gasoline medium-duty passenger vehicle (gross vehicl^e weight rating between 8,501-10,000 Ibs) with an odometer reading of approximately 50,000 miles was also tested and achieveda US06 PM emission value of 0.8 mg/mi, comparable to those measured from the lightduty test vehicles. One particular light-duty test vehicle had PM emissions in excess of 3 mg/mi, but CARB suspects tha.t because the vehicle was not designed or certified to a stringent US06 PM standard, the calibration strategy may not have been optimized for PM control over the US06 and further refinement to the calibration would likely address the issue including minimizing any enrichment events that directionally increase emissions.

Recently, U.S. EPA shared PM emission data from its full useful life program with CARB. The primary objective of the full useful life program was to establish the feasibility of Tier 3 PM standards at vehicle full useful life and investigate the contribution of lubricating ,oil to PM emissions in Tier 2 vehicles. More than two dozen passenger cars and light-duty trucks were tested for PM.emissions on the FTP and US06 cycles. Initial results showed high PM emissions in excess of 40 mg/mi from some of the vehicles over the US06 cycle. U.S. EPA later determined that silicone contamination from the use. of silicone exhaust transfer tubes in the emission sampling system was a major contributor to the measured PM mass emissions, especially on test cycles that generate high exhaust tempefatures such as the US06 cycle. As a result,Page 12

U.S. EPA re-tested a dozen vehicles and the new data show that all twelve vehicles, including a suspected oil burner, emit at levels less than 4 mg/mi PM on the US06 cycle.

In response to U.S. EPA's recent US06 testing and the discovery of the silicone contamination issue, CARB has initiated a test program to further investigate PM emissions on the US06 cycle and determine the feasibility of a more stringent standard. The test program aims to gather US06 PM emission data on both current and future engine technologies, such as port fuel injection, gasoline direct injection, turbocharging, and engine downsizing, and the test vehicles are being selected accordingly. While the test program is on-going and vehicles are still being tested, thus far, US06 PM data have been collected for eight port fuel injection vehicles, including one light-duty truck, and two gasoline direct injection vehicles. PM emissions over the US06 cycle from seven out of the ten vehicles were measured below 1 mg/mi while nine out of ten were measured below 4 mg/mi. The one vehicle that had PM emissions above 4 mg/mi also showed FTP emissions that exceeded the LEV II FTP PM standard, so it is likely that the vehicle was not operating within design specifications at the time of testing.

While the findings of the above test programs clearly show that current LEV II vehicles, which are not subject to PM standards under the LEV II SFTP program, are capable of complying with a 4 mg/mi US06 PM standard, there have been some concerns regarding future technologies, such as advanced gasoline direct injection and turbocharged, downsized engines. While these future technologies are expecied to increase cylinder pressures and temperatures and possibly the need for additional engine temperature control, CARB still believes the 4 mg/mi US06 PM standard is feasible. This is because affected Tier 3 vehicles will be equipped with improved PM control technologies needed to comply with the 3 mg/mi PM standard on the F^TP (in lieu of the 10 mg/mi PM standard that LEV II vehicles are certified to) and because additional calibration opportunities will exist as even today's LEV II vehicles, which are calibrated without PM control considerations over the US06 cycle, generally have emission levels below 4 mg/mi with compliance margin.

In summary, while CARB will continue to collect US06 PM emission data on future technologies, CARB believes the data currently available sufficiently supports a more stringent standard and recommends that U.S. EPA adopt a US06 PM standard of 4 mg/mi in the Tier 3 program. Additionally, should U.S. EPA adopt a more stringent standard in the final proposal, CARB recommends that the corresponding in-use standards also be lowered in accordance with any changes to the certification standards.Page 13

Comment 4— Optional Phase-In Formula for FTP and US06 PM Standards

U.S. EPA is proposing to phase-in Tier 3 FTP and US06 PM emission standards beginning with the 2017 model year with 100 percent compliance required in the 2021 model year. U.S. EPA has also proposed an optional alternative phase-in schedule that manufacturers may use to comply with the Tier 3 PM emission standards for these model years. This alternative phase-in schedule is based on a mathematical equation that provides credits for vehicles certified to the Tier 3 PM standards based on the year in which they are certified. Accordingly, vehicles certified to Tier 3 PM standards in earlier years would be worth more than those certified in later years. This alternative phase-in schedule is similar to one CARB adopted for vehicles meeting the LEV III PM standards. However, while the LEV III regulations explicitly state that 100 percent compliance is required at the end of the phase-in period, the proposed Tier 3 regulations do not. We believe that in order to maintain the emission benefits of the Tier 3 program, it is necessary to add language to the Tier 3 rule to clarify that a manufacturer that certifies its vehicles to this alternative phase-in schedule must still meet the requirement that 100 percent of those vehicles meet the applicable PM standards in the 2021 model year.Page 14



### Comments on Proposed Tier 3 On-Board Diagnostic Requirements

Currently U.S. EPA accepts On-Board Diagnostics (OBD) systems certified to CARB's OBD II regulation as systems also satisfying the federal OBD regulation. The NPRM proposes to codify this practice by adoption and incorporation by reference CARB's OBD II regulation (title 13, California Code of Regulations, section 1968.2) as approved on June 17, 2010, effective starting in 2017 model year, except for the following provisions: - sections 1968.2(a), (b), (k) are excluded - the tampering clause in section 1968.2(d)(1.4) is excluded - the camshaft/crankshaft alignment monitoring requirement in section 1968.2(e)(15.2.1)(C) would only apply to vehicles with variable valve timing systems.

The proposal also includes a requirement for manufacturers to perform additional demonstration testing of the evaporative system monitor capability and to report additional standardized data through the OBD system that would identify how many miles since the evaporative system leak detection monitor last completed.

Comment 1— Version of OBD II Regulation Adopted

Overall, CARB supports U.S. EPA's incorporation of the OBD II regulation section 1968.2 into the federal requirements. However, CARB adopted additional changes to the 2010 version of the OBD II regulation that is referenced in the proposal. Specifically, CARB adopted changes which became operative on August 7, 2012. The 2012 amendments to the OBD II regulation are considered minor and include changes to the permanent fault code requirements and in-use monitor performance requirements to address issues related to hybrid vehicles (including plug-in hybrid electric vehicles), delays to the required start date for three minor diesel-related monitors, and an extension to the allowance for particulate matter filter monitors to exclude detection of specific failure modes. CARB recommends that U.S. EPA adopt the more recent version of the OBD II regulation to be more closely aligned with California.

Comment 2— Camshaft/crankcase Alignment Monitoring Requirement

The proposal includes a specific exclusion for the requirement in the CARB OBD II regulation section 1968.2(e)(15.2.1)(C) that OBD systems must be able to detect a misalignment between the crankshaft and camshaft. This is not a technology-forcing requirement and has been in place for many years in California-certified OBD II systems. CARB believes that a reduction in diagnostic capability and emission benefit would result due to the exclusion of camshaft/crankshaft alignment monitors on vehicles without variable valve timing systems, because alignment malfunctions can routinely occur in-use due to timing belts slipping or being improperly installed duringPage 15

maintenance involving timing belt replacement. Therefore, CARB recommends that the proposed regulation language be changed by removing the specific section that limits camshaft/crankshaft alignment monitoring to only those vehicles equipped with variable valve timing systems.

Comment 3— Evaporative ^eak System Monitor

The NPRM proposes a requirement for manufacturers to phase-in a 0.020 inch leak detection monitor as CARB's OBD II regulation has required since the 2002 model year. CARB supports this change to align detection capability nationwide. Further, most manufacturers already extend this capability nationwide by certifying a single system that meets CARB requirements.

Further, U.S. EPA is proposing vehicles support and report a new standardized data parameter that will be used to indicate the distance traveled since the OBD evaporative system leak monitor was last completed successfully, if the system passed or failed during the monitoring event, and to store this data in non-volatile memory such that it can survive battery disconnects and on-board computer memory clear events. This proposed requirement is intend"ed to determine'whether off-board leak detection testing needs to be performed on individual vehicles during the In-Use Verification Testing (IUVP) program.

Concerning the^proposal for a`new standar • dized data parameter, CARB has worked with the SAE J1979 committee to develop ari updated standard to achieve this. However, the draft SAE proposal created to meet the intent does not completely align with the U.S. EPA proposed regulatory language. Specifically, it does not provide for the data to be stored in non-volatile memory but'instead has the value report a clear indication if the data has been erased and the monitor has not successfully run since then. In this situation, it appears to CARB that this will satisfy the intent and provide a clear indication that the off-board leak test should be performed on such a vehicle selected for IUVP testing. Secondly, the draft parameter indicates the mileage since the last successful test completion but does not directly indicate whether it was a pass or fail decision. Instead, current fault code status must be used and the absence (or presence) of an evaporative system leak fault code will confirm whether the monitor last ran and passed (or failed, respectively). Again, CARB believes this will provide the necessary data for the intended use in IUVP testing. Accordingly, CARB recommends the proposed language be modified in the final proposal to eliminate the requirement that the new data be able to survive battery disconnects and computer memory clear events as well as remove the requirement that the new parameter directly report whether the last monitoring event was a pass or a faiLPage 16

Comment 4— Evaporative System Activated Carbon Canister Monitor and Purge Monitor

Though not officially part of U.S. EPA's proposal, U.S. EPA seeks comments about a provision to require the OBD system to monitor the activated carbon canister, specifically for evidence of proper performance of the canister such as adequate adsorption and desorption of hydrocarbon vapors. U.S. EPA believes such performance could be sensed with existing hardware on the vehicle (e.g., looking for changes in canister carbon bed temperature or presence of vapor in the fuel going to the intake manifold after a cold start or refueling event). U.S. EPA also seeks comment on whether any device used to enhance or control purge flows, rates, or schedules (e.g., a vacuum pump or similar device used to assist vehicle engine vacuum purge} should be monitored by the OBD system.

CARB currently has no requirement for monitoring the canister performance but given the increasing importance of keeping evaporative emissions to a minimum, believes the idea merits further exploration and research before making any decisions on implementing any regulation changes. Important aspects that would likely need to be investigated include whether monitoring of the activated carbon canister can indeed be robustly done with the existing hardware on the vehicle. Regarding devices used to assist purge flow, increased usage of such devices in the future is possible, so further investigation into monitoring of these devices is warranted. However, CARB believes the OBD regulation already covers monitoring of these devices to some extent, since they would be considered evaporative system components and consequently required to be monitored under comprehensive components requirements for proper function.

Comment 5— Pressurized Fuel Tank Monitor

EPA also seeks comments about a provision regarding pressurized and sealed fuel tanks. Based on its observation of a trend towards fuel tanks with higher operating pressures or tanks sealed to the atmosphere during normal operation and data showing a leak in these systems will result in substantially higher emissions relative to traditional low pressure systems, U.S. EPA seeks comment on the feasibility and cost of requiring OBD leak detection monitors to detect a smaller diameter orifice on such systems — specifically, something in the magnitude of a 0.010 inch leak in lieu of a 0.020 inch leakanywhere in the evaporative system. This would apply to vehicles with a designed inuse operating pressure in excess of 0.36 psi (10 inches of water). For sealed tanks, U.S. EPA seeks comments on an added requirement that any valve that isolates the fuel tank vapor from the canister be defaulted to an open position at key off (allowing vapors to vent to the canister) if the OBD monitor detects a leak and illuminates the malfunction indicator light. Further, for pressurized systems, U.S. EPA is asking for comment on setting the evaporative system monitor threshold in the 0.010 inch to 0.015 inch range, specifically asking for the feasibility of this threshold, the effects of the ventPage 17

valve open requirement on on-board refueling vapor recovery, and the reparability of leaks below 0.020 inch.

CARB currently has no such requirements but given the increasing importance of keeping evaporative emissions to a minimum, believes the ideas merit further exploration and research before making any decisions on implementing any regulation changes. Important aspects that would likely need to be investigated include the feasibility of the repair service community to efficiently diagnose and repair detected leaks with a smaller diameter.Page 18



### Comments on Proposed Tier 3 In-Use Verification Program

The NPRM proposes additional measures to identify evaporative leaks on in-use vehicles based on studies performed by the Coordinating Research Council and Colorado Department of Public Health and Environment. Specifically, the NPRM proposes adding a test procedure to the IUVP focused on testing a broader sample of fuel/evaporative systems leaks in in-use vehicles. Moreover, the NPRM proposes the addition of an IUVP evaporative leak check requirement beginning with 2018 model year vehicles. This requirement would be included in the IUVP's low and high mileage tests for any volatile fuel powered vehicle (except diesel and natural gas) with a requirement that there be at least one representative vehicle for each evaporative/refueling/leak family evaluated at each year point. EPA is proposing this approach in lieu of creating a new set of requirements which would require a separate set of vehicles to be procured for testing. In addition, the NPRM is considering extending the age point for leak emission testing for IUVP beyond the current four year test point (e.g., testing vehicles six to eight years old) to better assess aged vehicles for evaporative leaks.

In response to reduced fuel sulfur levels in California and federal commercial gasoline, use of a sulfur purge preconditioning to reduce catalyst sulfur deposits prior to IUVP emission testing was disallowed by both CARB and U.S. EPA beginning in 2007. These purge procedures, which consist of high speed driving cycles not normally experienced as typical driving patterns, are designed to reduce sulfur and carbon deposits in the catalytic converter. Decreasing carbon build deposition in the exhaust system may have a positive impact on emissions but because carbon deposits are a result of real world driving conditions and fuel use, use of a sulfur purge procedure may produce a false representation of true in-use emissions. Nonetheless, the NPRM proposes to allow for conducting a sulfur purge cycle over the US06 test cycle for those manufacturers requiring a sulfur preconditioning test.

Comment 1- In-Use Verification Program Evaporative Leak Check

U.S. EPA is also proposing to conduct an evaporative leak test on vehicles that are 6 to 8 years old. Although this is doable for IUVP, the challenge will occur if enough vehicles fail the leak check for a given test group and the manufacturer must then conduct an In-Use Confirmatory Program. Under an In-Use Confirmatory Program, the manufacturer must procure ten properly maintained and used vehicles which creates a challenge because many of these vehicles will be out of warranty, sold to a second owner and/or operated beyond 75 percent of the certified useful life and may not be properly maintained. Accordingly, CARB recommends that U.S. EPA include language to require testing on vehicles no more than 6 years after the certified model year and within 75 percent of the useful life mileage. For example, a manufacturer would bePage 19

required to conduct evaporative leak testing on 2015 MY vehicles within 75 percent of the useful life mileage and before the end of the 2021 calendar year.

Comment 2- In-Use Verification Program Sulfur Purge Procedure for Sulfur Preconditioning.

As noted above, sulfur content of federal commercial fuel has been significantly reduced and, based on past IUVP test data, manufacturers have not been allowed to perform sulfur purge cycles since 2007 and have not experienced any test vehicles failing to meet the exhaust emission standards that were attributed to high sulfur deposits. CARB believes running additional sulfur cleariout procedures is unnecessary and should not be included as part of the IUVP or any in-use confirmatory test program.

^ f

. .Page 20



### Comments on Proposed Tier 3 F'uel Standards

CARB staff strongly supports the proposed Tier 3 gasoline sulfur standards and applauds the efforts of U.S. EPA staff for bringing our fuel programs in alignment. CARB staff also supports the proposed requirements for midlevel ethanol blends, as well as promoting the powerplant design advantages of an E30 blend. CARB staff offers the following comments in support of the proposed gasoline sulfur standards and to further harmonize fuel program requirements of the two agencies.

Comment 1— Gasoline Sulfur Standards

U.S. EPA is proposing to lower the sulfur standard in gasoline and ethanol-gasoline blends to a 10 parts per million (ppm) annual average. California's gasoline already meets the proposed 10 ppm sulfur standard. For many years California has led the nation in gasoline quality, including a low-sulfur standard. On December 31, 2003, California lowered the sulfur cap on gasoline from 80 ppm to 60 ppm. Then on December 31, 2005, the sulfur cap was lowered from 60 ppm to 30 ppm. And finally, on December 31, 2011, the sulfur cap was lowered to 20 ppm. The 20 ppm sulfur cap brought the in-use fuel's sulfur average in California to about 9 ppm.

Sulfur reduction has been one of the most cost--effective changes that have been made to California's gasoline. California's low-sulfur gasoline has reduced emissions by approximately 400 tons per day (tpd) of hydrocarbon emissions, 129 tpd of oxides of nitrogen emission (NOx), 34 tpd of oxides of sulfur emissions, and 1300 tpd of carbon monoxide emissions 3 . Fuel/vehicle emission studies used in the development of California's Predictive Model have shown that lower sulfur in gasoline results in lower NOx emissions, lower exhaust tailpipe hydrocarbon emissions, and lower toxics emissions 4 . In addition, low sulfur reduces potential catalyst deactivation from sulfur contamination in vehicle emission control systems.

CARB staff estimates that California's reformulated gasoline (CaRFG) program cost about 2 to 5 cents per gallon. Of that, staff estimates costs as low as 0.6 cents per gallon being attributable to lowering sulfur in CaRFG. Accordingly, the Tier 3 gasoline sulfur standard's estimated cost of 0.89 cents per gallon is in line with California's estimated cost of lowering sulfur.

In conclusion, CARB staff believes that U.S. EPA's Tier 3 gasoline sulfur standards will provide cost-effective emission reductions. CARB staff strongly supports U.S. EPA's Tier 3 gasoline sulfur standards and applauds the efforts of U.S. EPA's staff for bringing our gasoline fuel programs into alignment.

2 http://www.arb.ca.govlreqact/2012/Ieviiiqhg2012/levisor_pdf 3 http:!/www.arb.ca.gov/board/books12007/022207!07-2-2pres.pdf 4 http://www.arb.ca.gov/fuels/gasoline/premodellpmdevelop.htmPage 21



### Comments on Proposed Tier 3 Certification Test Fuel Specifications

CARB staff disagrees with U.S. EPA's decision to propose 15 percent by volume ethanol gasoline (E15) as the Tier 3 certification test fuel. Additionally, CARB recommends reciprocity with California's gasoline certification fuel beyond 2020 and throughout the lifetime of the Tier 3 program. CARB offers the following comments in support of our recommendation in an effort to further harmonize certification fuel program requirements of the two agencies.

Comment 1— Gasoline Certification Test Fuel

CARB recommends that the U.S. EPA reconsider the use of E15 as the Tier 3 certification fuel. Instead, CARB recommends a certification fuel with 10 percent volume ethanol (E10) and a 9.0 pounds per square inch (psi) RVP. An E10 certification fuel would be.consistent with the current federal commercial fuel. In addition, the 9.0 psi RVP vvould allow the Tier 3 program and California's LEV III program to be consistent with the certification fuel reciprocity precedent set between the Tier 2 program and California's LEV II program. The evaporative emission difference between U.S. EPA's 9.0 psi RVP Tier 2 certification fuet,and California's LEV II 7.0 psi RVP certification fuel was offset by U.S. EPA's use of a lower diurnal temperature range. California's LEV III certification fuel has approximately a 7.0 psi RVP and CARB staff recommends that U.S. EPA maintain a 9; 0 psi RVP fuel such that the evaporative emission offssts between the California LEV lll certification fuel and the Tier 3 certification fuel can be maintained.

E15 is currently used in a handful of fueling stations nationwide and its further penetration into the marketplace is uncertain. Given the practical considerations inherent in providing a refueling infrastructure for E15, it may not proliferate very rapidly into the marketplace. On the other hand, E10 has been tested thoroughly as a viable fuel for all vehicles currently on the road and, as a result, will likely be widely used for the foreseeable future. However, should E15 constitute a significant fraction of the federal commercial fuel market at some future date, it would be appropriate at that time for U.S. EPA to reconsider the composition of Tier 3 certification fuel.

Comment 2— Certification Fuel Reciprocity

As proposed, Tier 3 provides reciprocity for certification fuel between the LEV III and Tier 3 programs until model year 2020, at which time U.S. EPA will only recognize emission certification on federal certification fuel. Traditionally, the two agencies have granted reciprocity for certification fuel when demonstrating emission compliance, thus providing a degree of compliance flexibility to vehicle manufacturers without impacting the emission benefits of the California or federal programs. CARB believes this should continue to hold true whether Tier 3 certification fuel is E15 as currently proposed orPage 22

E10 (see our previous comment though on the impact of an RVP of 10 on reciprocity concerns for evaporative emission testing) and strongly recommends continuing the practice of providing reciprocity for certification fuel in the Tier 3 program beyond 2020 and throughout the lifetime of the Tier 3 program.Page 23



### Comments on Costs and Economic Impacts of Tier 3 Proposal

CARB staff supports the approach used to evaluate the economic impacts of U.S. EPA's Tier 3 proposal.

Due to the differences in regulatory scope, timeframes, and geography, a direct comparison to CARB's LEV III economic impact analysis is incompatible. Nowever, given that the proposal's compliance costs and cost-effectiveness metrics are on the same order of magnitude as those estimated by CARB in previous related rulemakings, CARB staff concurs with U.S. EPA's overall conclusions on the direction and magnitude of economic impacts to the auto and refinery sectors. However, some time has passed since the initial evaluation of technology costs detailed in the draft Regulatory Impact Analysis. Therefore, it may be appropriate for U.S. EPA to revisit those costs estimates to determine if any revisions are warranted.

While health and other ancillary benefits were not formally quantified in CARB's most recent LEV III rulemaking, in the past CARB has used a similar method to the one employed in the proposal for monetizing health benefits. Additionally, we believe that given the magnitude of compliance costs relative to the size of the domestic economy, U.S. EPA's more qualitative approach for estimating employment effects using the Morgenstern et al. framework instead of relying on economy-wide modeling is reasonable.Page 24



### Comments on Subpart L--Methods for Unregulated and Special Pollutants

CARB supports U.S. EPA's attempt to quantify the semi-volatile organic compound (SVOC) emissions from gasoline vehicle exhaust. There is a need to understand if advanced combustion and emission control technologies targeting criteria and greenhouse gas pollutants also lead to SVOC reduction. However, CARB has several concerns that require U.S. EPA clarification. CARB believes U.S. EPA should modify its definition of SVOCs. CARB recommends that U.S. EPA align the SVOC sampling method with the PM gravimetric determination if it is used for certification and compliance. In addition, the proposed SVOC sampling media and extraction procedure are tightly specified. U.S. EPA should allow flexibility or alternatives. Given that target analytes, analytical methods, and data reporting are not specified in the NPRM, our ability to comment is limited.

Comment 1 - SVOC de^nition, §1065.1103(e)(3)

The U.S. EPA states that "Most SVOCs have at least 14 carbon atoms per molecule and have a boiling point between 240°C and 400°C.....". This statement suggests that U.S. EPA's operational definition of semi-volatile compounds would exclude C10 —C13 polynuclear aromatic hydrocarbons (PAH) which are known to be semi-volatile in nature. Therefore we suggest that U.S. EPA rephrase this statement as follows: "Most SVOCs have at least 14 carbon atoms per molecule or have a boiling point between 240°C and 400°C.....".

Comment 2- SVOC sampling modules storage, §1065.1103(b)

The NPRM recommends "Blank sorbent modules with inlet and outlet covered (i.e., field blanks) should periodically accompany the test sample train throughout the course of a test, including the sample train and sorbent module disassembly, sample packaging, and storage".

CARB suggests U.S. EPA revise this to read "Blank sorbent modules (i.e. field blanks) should be stored in a sealed environment and should periodically accompany the test train...". CARB believes the term "cover" is too vague for sorbent modules as the sample collection is a passive diffusive mechanism; depending on how the sample module is "covered" the blank level can vary and may not provide the information needed for field blanks. U.S. EPA should also allow the flexibility of designing a custom SVOC sampler or sorbent module.Page 25

Comment 3- SVOC sampling system design, §1065.1105

The NPRM recommends SVOC sampling from undiluted emissions to minimize the amount of SVOC's lost and recommends using a heated sample probe with a set point no higher than 200°C.

CARB agrees that sampling SVOC directly from the emission source may reduce the SVOC loss in the dilution system. However, the temperature of undiluted exhaust is usually higher than the temperature specified for PM mass gravimetric determination (47±5°C). Therefore, the gas-particle partition of SVOC will favor the gas phase and the partition will not be consistent with the determination of PM mass. CARB believes that the specified 200°C setting is logically in conflict with the U.S. EPA statement that SVOCs typically have boiling points starting at 240°C. U.S. EPA should clarify the rationale and goals for the 200°C setting.

Comment 4- SVOC sampling media selection, §1065.1105(c )

The NPRM recommends using 110 mm or 293 mm "pure" quartz filter and 40 g XAD-2 at an average flow rate of 70 Umin for SVOC sampling.

CARB believes U.S. EPA should allow flexibility in sample media selection if equivalent performance can be demonstrated. Based on'CARB's experience, a 47mm Teflon coated glass fiber filter followed by 7g of XAD-4 sandwiched with PUF shows no breakthrough of PANs when used for diluted exhaust sampling. Furfhermore it's not clear whether the integrity of the quartz fiber ^ilter is maintained and can be used for sampling after cleaning with the Soxhlet method. A more appropriate cleaning procedure for quartz fiber filters should include baking in the oven to remove carbonaceous components.

Comment 5—SVOC sample recovery method, §1065.1109 (a)(2)-(4)

The NPRM recommends a method to recover the potential SVOC lost in the sampling probe, transfer line, and/or filter holder with solvent.

CARB believes that this recovery process will result in higher uncertainty when quantifying SVOCs at low emission levels due to several factors including: the impurities in the large volume of solvent used for recovery, contamination from the environment where the recovery is conducted, and the variability of the recovery operation. The proposed recovery process will also extend vehicle testing time. Therefore, U.S. EPA should specify the frequency of conducting sample train recovery.Page 26

Comment 6- SVOC isotopically labeled standards spiking procedure, §1065.1107 (C)

The NPRM language for determining the extraction efficiency of SVOC adsorbed to the sample media using isotopically labeled standards (surrogate standard) is not clear.

CARB believes that when these standards are spiked before sampling is carried out, the recovered surrogate standards account for both the potential losses/gain during sampling as well as in the extraction process (sample analysis). Uncertainties are also introduced when a 60 minute waiting period is required for solvent evaporation. CARB recommends U.S. EPA clarify how this surrogate standard will be used as well as the use of the recovery standard used in analyses (§1065.1111) which determine the extraction efficiency of the analytical methods.

Comment 7- SVOC sample extraction, §1065.1109(b)

The NPRM describes detailed sample media cleaning and sample extraction procedures with the Soxhlet extraction method.

CARB believes that U.S. EPA should allow alternative methods if they demonstrate equivalent performance in terms of cleaning and extraction efficiency compared to the Soxhlet method. CARB MLD SOP#144 uses the Dionex Automated Solvent Extractor (ASE) to extract SVOC samples. The ASE shortens sample preparation time and reduces labor cost, and can be considered as an acceptable alternative to the Soxhlet method. In addition, CARB believes the proposed method should also allow the filter and XAD-2 to be extracted either separately or combined, depending on the data need.

## ' _^^

^^ ^ r a^^ 

# _:^^:^

ti 

# ^

f:^^ f^

^

_



### ^ ^ N

N ^

^ 

### _ ^ ^M ^ —^ ^ O 

### U _ ^

—^

— ^ ^ca ^n ^ M

^ _ LL

U ^

^ o — ^ Y

_ U

— O O



# °" V U ^ ^
^ N O

^ Q ^ > _^ ^ >

O Z ^ ^ U C ^ ^ ^ c6 ^ W ^

a ^ Q ^ ^ Z -Q v ^ O ^ ^ ^ o p ^

^^ ^ ^ U a^ ^ a^i a^i a^ `^ EU?0_Y

— ^ ' C ^ ^' O ^ ^ ^ Y C p 0

^ Q ^ O ^ m C ^ c O ^ mW^^ C

^ ^U j ^o N > c^o ^ Q ^ W ^ > Q



# n

^I

^ ^

^ ~ 00 N 

### W N
.ti ^ ^ ^ W N O1

a ^ V ;^^.

^ a ^ ^ W ^

^i `

u ^a ^ ^ ^
d^ ^ C L

C^

... CC U



## f