California: Light-duty: Emissions

California: Light-duty: Emissions


California’s Low Emission Vehicle (LEV) standards impose fleet-wide criteria pollutant and GHG-Emissions Standards for Light-Duty Vehicles. Under LEV III – which combines GHG and particulate emissions into one regulatory package –  gradually stricter requirements are being phased in from 2015 to 2025.

Standard type
Criteria pollutant emission limits and greenhouse gas emission standards (note: for California’s dedicated GHG programs, see the California: Light-duty: GHG page)

Passenger cars, Light-duty trucks, and medium-duty vehicles below 14,000 lbs gross weight


LEV I (1994-2003) & LEV II (2004-2015): Criteria Pollutant Regulations

The California Air Resources Board (CARB) first adopted Low Emission Vehicle (LEV) standards in 1990. These standards ran from the 1994 model year through 2003. At its November 1998 meeting, CARB amended this set of regulations (now referred to as LEV I) to create the new, LEV II standards, which affect passenger cars, light-duty trucks, and medium-duty vehicles. LEV II regulations were formally adopted in 1999, and became applicable with the 2004 model year.

LEV III (2015-2025): Criteria Pollutant and Greenhouse Gas Regulation

CARB adopted the LEV III amendments to California’s Low Emission Vehicle (LEV) regulations in January 2012. The LEV III Program amendments include more stringent emission standards for both criteria pollutants and greenhouse gases for new passenger vehicles, and were adopted along with an updated zero-emission vehicle (ZEV) program, as part of the Advanced Clean Cars (ACC) Program. LEV III includes criteria pollutant emission limits that will be phased-in from 2015 through 2028, and GHG emission standards for model years 2017-2025.1

Technical Standards

LEV I (1994-2003)

LEV I California emission standards, which applied through model year 2003, can be found on the California: Light-duty: LEV I page.

LEV II (2004-2015)

LEV II standards were established to meet air pollutant emission standards in the federally mandated State Implementation Plans (SIPS). LEV II standards are in effect until LEV III standards begin in 2015. The LEV II Program is composed of LEV II, Ultra Low Emission Vehicle (ULEV II), Super Ultra Low Emission Vehicle (SULEV), and ZEV standards, or “bins,” for certifying light-duty vehicles. Similar to the federal light duty vehicle “Tier 2” criteria pollutant program, individual vehicle models are certified to a specific bin or category, and a manufacturer’s corporate average certification across all vehicles sold must meet a designated average for tailpipe emissions. LEV II certification is equivalent to Bin 5 of the federal Tier 2 program, while California SULEV certification is approximately equivalent to federal Bin 2.

The current LEV II required average is a 0.035 g/mi non-methane organic gas (NMOG) fleet average, which is between the ULEV and SULEV certification standard limits. The California LEV II program allows fleet averaging for NMOG emission certification, while the federal EPA Tier 2 program allows fleet averaging of NOx certification emission levels. Light-duty truck and medium-duty vehicle categories below 8,500 lbs gross weight were reclassified in LEV II and have to meet passenger car requirements. As a result, most pick-up trucks and sport utility vehicles are required to meet the same standards as other passenger vehicles under the LEV II program. The reclassification was phased-in by 2007.

Three sets of emission standards are defined as LEV, ULEV, and SULEV. A fourth emission category, PZEV (partial zero emission vehicle), has the same test emission levels as SULEV, but also includes additional evaporative emissions control and a 150,000 mile/15 years emission durability. A fifth category, ZEV, has zero test cycle tailpipe emissions. Emission standards are summarized in the following tables.

Additional information can be found in the LEV II legislative text and on the CARB LEV II website.

LEV II Emission Standards for Passenger Cars and LDVs < 8500 lbs, g/mi
Category 50,000 miles/5 years 120,000 miles/11 years
LEV 0.075 3.4 0.05 0.015 0.090 4.2 0.07 0.01 0.018
ULEV 0.040 1.7 0.05 0.008 0.055 2.1 0.07 0.01 0.011
SULEV 0.010 1.0 0.02 0.01 0.004
LEV II Emission Standards for Medium-Duty Vehicles, Durability 120,000 miles, g/mi
Weight (GVW) Category NMOG CO NOx PM HCHO
8,500 – 10,000 lbs LEV 0.195 6.4 0.2 0.12 0.032
ULEV 0.143 6.4 0.2 0.06 0.016
SULEV 0.100 3.2 0.1 0.06 0.008
10,001 – 14,000 lbs LEV 0.230 7.3 0.4 0.12 0.040
ULEV 0.167 7.3 0.4 0.06 0.021
SULEV 0.117 3.7 0.2 0.06 0.010

Under the LEV II regulation, NOx and PM standards for all emission categories are significantly tightened compared to the LEV levels. The same standards apply to all vehicles regardless of fuel (under revisions adopted on 15 November 2001, gasoline vehicles are no longer exempted from the PM standard). Light-duty LEVs and ULEVs certify to a 0.05 g/mi NOx standard, phased-in starting with the 2004 model year. A full useful life PM standard of 0.010 g/mi (or 10 mg/mi) is introduced for light-duty vehicles and trucks less than 8,500 lbs GVW certifying to LEV, ULEV, and SULEV standards. With the LEV II emission standards can only be met by vehicles with advanced emission control aftertreatment technologies. In the case of diesels, vehicles generally require particulate filters and NOx reduction catalysts.

Fleet Emission Requirements – LEV II standards also include provisions that require automakers to reduce their vehicle fleet emission levels from vehicles sold for the California market each year through 2010 – the last year of the LEV II phase-in period. In the case of light-duty vehicles, manufacturers must meet increasingly tighter fleet average NMOG standards. For example, the final (2010) LEV II fleet average NMOG standard is 0.035 g/mi for PC/LDT1 and 0.043 g/mi for LDT2. Medium-duty vehicles have no fleet average standards, but manufacturers are required to certify increasing percentages of their MDVs to the applicable emission standards. Evaporative emission standards were also increasingly tightened through 2010.

Comparative analysis – While the California LEV II program is similar in structure to the federal Tier 2 legislation, there are a number of differences regarding overall fleet emission stringency, durability, and categorization of vehicles. One difference is that the federal approach uses eight certification bins to allow for greater emission level diversification in the fleet.

The table below shows the percentage breakdown of vehicles certified for sale in California at the various emission categories—based on NMOG certification—in model year 2008.

California MY 2008 Emission Certification Levels for NMOG
Category LEV ULEV SULEV* Sales Volume
PC/LDT1 18% 50% 32% 1,028,000
LDT2 30% 66% 4% 560,000
MDV 35% 65% 0% 29,000
Total 23% 55% 22% 1,618,000
* Includes PZEV, which accounted for 92% of the SULEV+PZEV category
Note: Vehicle definitions are introduced on the California: Vehicle Definitions page

LEV III (2015-2025)

The LEV III exhaust emission standards will be phased in over the 2015 through 2025 model years. The LEV III regulations include new criteria pollutant emission standards and new GHG standards. Specifically, LEV III sets the acceptable GHG emission levels from new 2017 and subsequent model year passenger cars, light-duty trucks, and medium-duty passenger vehicles. The fleet average CO2 exhaust mass emission target values are indexed by vehicle footprint for vehicles that are produced and delivered for sale in California each model year, and these targets and other details can be found on the California light-duty GHG page.

LEV III will modify the LEV II standards in a few notable ways. LEV III will:

  • Combine NMOG and NOx standards into one NMOG+NOx standard,
  • Implement a more stringent combined NMOG+NOx fleet average requirement for 2015-2025 model years to reduce these emissions by approximately 70%,
  • Add several emission standard bins throughout the lower NMOG+NOx emission levels to provide greater flexibility in complying with the lower fleet average standards, and
  • Increase the durability requirements for emission control systems.

Particulate Matter Standards – The PM mass emission standard will be tightened under LEV III. The LEV II limit of 10 mg/mi (0.010 g/mi) will apply through model year 2016. Then a 3 mg/mi will be phased in through 2017-2021, and all new vehicles by model year 2021 will certify to the new 3 mg/mi limit (and be allowed an in-use PM compliance standard of 6 mg/mi). Finally, a 1 mg/mi PM standard will be phased in starting in 2025 and applicable for all new model year 2028 light-duty vehicles. The medium duty vehicle PM limits are similarly tightened.

LEV III Particulate Matter Emission Standards
Vehicle Type PM limit
Phase-in period
PCs, LDTs, MDPVs 3 2017-2021
1 2025-2028
MDVs 8,501-10,000 lb 8 2017-2021
MDVs 10,001-14,000 lbs 10 2017-2021

LEV III emission categories and the FTP-75 certification emission levels for light-duty vehicles and medium-duty passenger vehicles are listed in the table below. Allowance for NMOG+NOx fleet averaging was adopted to facilitate greater flexibility for automaker compliance with the more stringent standards and provide a closer linkage to the federal program bins with more bins. Note that the PM limits below apply only to vehicles that do not meet the more stringent requirements (ultimately 1 mg/mi for all LDVs by model year 2028) under the phase-in described above.

LEV III Emission Standards for new 2015 and subsequent LDVs
Durability 150,000 miles
Emission Category NMOG+NOx
LEV160 0.160 4.2 4 0.01
ULEV125 0.125 2.1 4 0.01
ULEV70 0.070 1.7 4 0.01
ULEV50 0.050 1.7 4 0.01
SULEV30 0.030 1.0 4 0.01
SULEV20 0.020 1.0 4 0.01
† Applies to all passenger vehicles, light-duty trucks less than or equal to 8500 lbs GVW (loaded vehicle weight), and all medium-duty passenger vehicles.
* Applicable only to vehicles not included in the phase-in of the final PM standards

LEV III emission categories and the FTP-75 standards for chassis-certified medium-duty vehicles (MDVs) are shown below. The LEV III legislation would not change emission standards for engine-certified MDVs.

LEV III Emission Standards for new 2015 and subsequent MDVs
Durability 150,000 miles
Vehicle Type Emission Category NMOG+NOx
MDVs 8501 – 10,000 lbs LEV395 0.395 6.4 6 0.12
ULEV340 0.340 3.2 6 0.06
ULEV250 0.250 2.6 6 0.06
ULEV200 0.200 2.6 6 0.06
SULEV170 0.170 1.5 6 0.06
SULEV150 0.150 1.5 6 0.06
MDVs 10,001 – 14,000 lbs LEV630 0.630 7.3 6 0.12
ULEV570 0.570 3.7 6 0.06
ULEV400 0.400 3.0 6 0.06
ULEV270 0.270 3.0 6 0.06
SULEV230 0.230 1.7 6 0.06
SULEV200 0.200 1.7 6 0.06
† ALVW (adjusted loaded vehicle weight)
* Applicable only to vehicles not included in the phase-in of the final PM standards

Fleet Emission Requirements – For light-duty vehicles, the fleet-wide target for NMOG+NOx emissions for model year 2025 is equivalent to the SULEV emission level of 0.030 g/mi. Based on the emission certification and sales volume figures, the average NMOG+NOx emissions in 2008 were 0.112 g/mi. Therefore, the LEV III fleet average requirements would result in a 73% reduction of NMOG+NOx emissions by 2025. For chassis-certified medium-duty vehicles, the fleet average requirements for NMOG+NOx are:

  • GVW 8,500 – 10,000 lbs: 0.170 g/mi
  • GVW 10,000 – 14,000 lbs: 0.230 g/mi

Durability – The LEV III standards phase-in a new 150,000 miles durability requirement, compared to the LEV II 50,000 and 120,000 miles standards. Manufacturers receive a 0.005 g/mi FTP NMOG+NOx emission credit for extended, 150,000-mile warranty coverage.

Evaporative Emissions – All light-duty vehicles will have to meet more stringent “zero evaporative emission” standards, while using more challenging testing procedures.

Direct Ozone Reduction Credit – Manufacturers receive an NMOG credit for direct ozone reduction systems (such as ozone reducing catalysts coated on vehicle radiators). The in-use performance of the system must be monitored via an on-board diagnostic system.

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