Cal. Code Regs. Tit. 13, § 2708 - Determination of Emissions Reduction

(a) Calculation of Emissions Reduction. The emissions reduction verified for a diesel emission control strategy is based on the average of all valid test results before (baseline) and after (control) implementation of the diesel emission control strategy. Test results from both emission testing and durability testing are to be used. If the applicant chooses to perform either the initial or the final durability baseline test, but not both, it must use those results to calculate the reductions obtained in both the initial and final control tests.

(1) Percentage Reduction. The percentage reduction for a given pair of baseline and control test sets (where a "set" consists of all test cycle repetitions, e.g., the test set of 3 hot-start UDDS tests) is the difference between the average baseline and average control emissions divided by the average baseline emissions, multiplied by 100 percent. The average of all such reductions, as shown in the equation below, is used in the verification of a diesel emission control strategy.

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Where:

[SUMMATION]=	sum over all control test sets
baselineAVG or controlAVG=	average of emissions from all baseline or control test repetitions within a given set

(A) For any test set involving cold and hot starts, the time weighted emission result is to be calculated by weighting the cold-start emissions by one-seventh ( ¹/₇) and the hot-start emissions by six-sevenths ( ⁶/₇) as shown below.

Weighted Emission Result=¹/₇ * average cold-start emissions + 6/7^* average hot-start emissions

(B) For applicants that request verification of NOx reductions from on-road applications and submit additional test data pursuant to section 2703(e)(1)(C), weighted test results from the additional test set are included in the percentage reduction equation above. The Executive Officer shall determine an appropriate weighting factor in consultation with the applicant based on factors including, but not limited to, the amount of time that vehicles within the selected emission control group have elevated NOx emissions and the breadth of engines and applications encompassed by the emission control group.

(2) The absolute emission level is the average control emission level, as defined in the following equation:

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(b) Categorization of the Diesel Emission Control Strategy. The Executive Officer shall categorize diesel emission control strategies to reduce PM and NOx emissions based on their verified emission reductions according to Table 1 in section 2702. For a diesel emission control strategy to be verified at a given Level or Mark, the emission reductions demonstrated by each test set submitted with the application must be greater than or equal to the minimum reduction that defines the Level or Mark. It is not sufficient for the average reduction to exceed the minimum value of the Level or Mark if one of the reductions in the average is below the minimum.

(1) Diesel emission control strategies are categorized by their PM reductions as follows:

(A) Level zero: the system has been demonstrated under these procedures to reduce PM emissions by less than 25 percent from the baseline emission level and to reduce NOx emissions by at least 25 percent from the baseline emission level.

(B) Level one: the system has been demonstrated under these procedures to reduce PM emissions by at least 25 percent from the baseline emission level.

(C) Level two: the system has been demonstrated under these procedures to reduce PM emissions by at least 50 percent from the baseline emission level.

(D) Level three: the system has been demonstrated under these procedures to reduce PM emissions by at least 85 percent from the baseline emission level, or to achieve PM emission levels of 0.01 grams per brake-horsepower-hour (g/bhp-hr) or less.

(2) Diesel emission control strategies are categorized by their NOx reductions as follows:

(A) Mark 1: the system has been demonstrated under these procedures to reduce NOx emissions by at least 25 percent from the baseline emission level.

(B) Mark 2: the system has been demonstrated under these procedures to reduce NOx emissions by at least 40 percent from the baseline emission level.

(C) Mark 3: the system has been demonstrated under these procedures to reduce NOx emissions by at least 55 percent from the baseline emission level.

(D) Mark 4: the system has been demonstrated under these procedures to reduce NOx emissions by at least 70 percent from the baseline emission level.

(E) Mark 5: the system has been demonstrated under these procedures to reduce NOx emissions by at least 85 percent from the baseline emission level.

Notes

Cal. Code Regs. Tit. 13, § 2708

1. New section filed 5-12-2003; operative 6-11-2003 (Register 2003, No. 20).
2. Amendment filed 1-20-2009; operative 2-19-2009 (Register 2009, No. 4).
3. Amendment of section and NOTE filed 8-15-2013; operative 10-1-2013 (Register 2013, No. 33).

Note: Authority cited: Sections 39002, 39003, 39500, 39600, 39601, 39650- 39675, 40000, 43000, 43000.5, 43011, 43013, 43018, 43105, 43600, 43700 and 43830.8, Health and Safety Code. Reference: Sections 39650- 39675, 43000, 43009.5, 43013, 43018, 43101, 43104, 43105, 43106, 43107 and 43204- 43205.5, Health and Safety Code; and Title 17 California Code of Regulations Section 93000.

1. New section filed 5-12-2003; operative 6-11-2003 (Register 2003, No. 20).
2. Amendment filed 1-20-2009; operative 2-19-2009 (Register 2009, No. 4).
3. Amendment of section and Note filed 8-15-2013; operative 10-1-2013 (Register 2013, No. 33).