California Air Resources Board

California Air Resources Board Laboratory, Los Angeles, in 1973

The division assesses the extent of California's air quality problems and the progress being made to abate them, coordinates statewide development of clean air plans and maintains databases pertinent to air quality and emissions. The division's technical support work provides a basis for clean air plans and CARB's regulatory programs. This support includes management and interpretation of emission inventories, air quality data, meteorological data and of air quality modeling.[6]

The Air Quality Planning and Science Division has five branches:

• Emission Inventory Branch
• Modeling & Meteorology Branch
• Air Quality Data Branch
• Air Quality & Transportation Planning Branch
• Mobile Source Analysis Branch

The Atmospheric Modeling & Support Section is one of three sections within the Modeling & Meteorology Branch. The other two sections are the Regional Air Quality Modeling Section and the Meteorology Section.[6]

The air quality and atmospheric pollution dispersion models[7][8] routinely used by this Section include a number of the models recommended by the U.S. Environmental Protection Agency (EPA). The section uses models which were either developed by CARB or whose development was funded by CARB, such as:

• CALPUFF – Originally developed by the Sigma Research Company (SRC) under contract to CARB. Currently maintained by the TRC Solution Company under contract to the U.S. EPA.
• CALGRID – Developed by CARB and currently maintained by CARB.[9]
• SARMAP – Developed by CARB and currently maintained by CARB.[10]

Alternative Fuel Vehicle Incentive Program (also known as Fueling Alternatives) is funded by the California Air Resources Board (CARB), offered throughout the State of California and administered by the California Center for Sustainable Energy (CCSE).[12]

Smog in San Gabriel, May 1972

The CARB first adopted the Low-Emission Vehicle (LEV) Program standards in 1990 to address smog-forming pollutants,[13][14] which covered automobiles sold in California from 1994 through 2003. An amendment to the LEV Program, known as LEV II, was adopted in 1999, and covered vehicles for the 2004 through 2014 model years.[15] Greenhouse gas (GHG) emission regulations were adopted in 2004 starting for the 2009 model year, and are named the "Pavley" standards after Assemblymember Fran Pavley, who had written Assembly Bill 1493 in 2002 to establish them.[16][17] A second amendment, LEV III, was adopted in 2012, and covers vehicles sold from 2015 onward for both smog (superseding LEV II) and GHG (superseding Pavley) emissions.[18][19] The rules created under the LEV Program have been codified as specific sections in Title 13 of the California Code of Regulations;[20] in general, LEV I is § 1960.1; LEV II is § 1961; Pavley is § 1961.1; LEV III is § 1961.2 (smog-forming pollutants) and 1961.3 (GHG). The ZEV regulations, which were initially part of LEV I, have been broken out separately into § 1962.[21]

For comparison, the average new car sold in 1965 would produce approximately 2,000 lb (910 kg) of hydrocarbons over 100,000 mi (160,000 km) of driving; under the LEV I standards, the average new car sold in 1998 was projected to produce hydrocarbon emissions of 50 lb (23 kg) over the same distance, and under LEV II, the average new car in 2010 would further reduce hydrocarbon emissions to 10 lb (4.5 kg).[22]

In 2005, the California State Assembly passed AB 1229, which required all new vehicles manufactured after January 1, 2009 to bear an Environmental Performance Label, which scored the emissions performance of the vehicle on two scales ranging between 1 (worst) and 10 (best): one for global warming (emissions of GHG such as N
₂O, CH
₄, air conditioning refrigerants, and CO
₂) and one for smog-forming compounds (non-methane organic gases (NMOG), NO
_x, and HC).[23][25] The Federal Government followed suit and required a similar "smog score" on new vehicles sold starting in 2013; the standards were realigned for labels applied to 2018 model year vehicles.

The LEV program has established several categories of reduced emissions vehicles. LEV I defined LEV and ULEV vehicles, and added TLEV and Tier 1 temporary classifications that would not be sold after 2003. LEV II added SULEV and PZEV vehicles, and LEV III tightened emission standards. The actual emission levels depend on the standards in use.

• LEV (Low Emission Vehicle): The least stringent emission standard for all new cars sold in California beyond 2004.
• ULEV (Ultra Low Emission Vehicle): 50% cleaner than the average new 2003 model year vehicle.
• SULEV (Super Ultra Low Emission Vehicle): These vehicles emit substantially lower levels of hydrocarbons, carbon monoxide, oxides of nitrogen and particulate matter than conventional vehicles. They are 90% cleaner than the average new 2003 model year vehicle.

LEV I defined emission limits for several different classes of vehicle, including passenger cars (PC), light-duty trucks (LDT), and medium-duty vehicles (MDV). Heavy-duty vehicles were specifically excluded from LEV I. LEV I also defined a loaded vehicle weight (LVW) as the vehicle's kerb weight plus an allowance of 300 lb (140 kg). In general, the most stringent standards were applied to passenger cars and light-duty trucks with a LVW up to 3,750 lb (1,700 kg) (these "light" LDTs were later denoted LDT1 under LEV II).[14] LEV II increased the scope of vehicles classed as light-duty trucks to encompass a higher GVWR up to 8,500 lb (3,900 kg), compared to the LEV I standard of 6,000 lb (2,700 kg). In addition, LEV I had defined less stringent limits for heavier LDTs (denoted LDT2 with a LVW 3,751–5,750 lb (1,701–2,608 kg)); LEV II closed that discrepancy and defined a single emissions standard for all PCs and LDTs.[15] Under LEV III, medium-duty passenger vehicles (MDPV) were brought under the most stringent standards alongside PCs and LDTs.[18]

Rather than providing a single standard for vehicles based on age, purpose, and weight, the LEV I standards introduced different tiers of limits for smog-forming compound emissions starting in the 1995 model year. After 2003, LEV was the minimum standard to be met.[14]

Sunlight filtered through smog near Blythe, May 1972

CARB adopted regulations for limits on greenhouse gas emissions in 2004 starting with the 2009 model year to support the direction provided by AB 1493.[16] In June 2005, Governor Arnold Schwarzenegger signed Executive Order S-03-05, which required a reduction in California GHG emissions, targeting an 80% reduction compared to 1990 levels by 2050.[27] Assembly Bill 32, better known as the California Global Warming Solutions Act of 2006, codified these requirements.[28]

CARB filed a waiver request with the United States Environmental Protection Agency (EPA) under Section 209(b) of the Clean Air Act in December 2005 to permit it to establish limits on greenhouse gas emissions; although the waiver request was initially denied in March 2008, it was later approved on June 30, 2009 after President Barack Obama signed a Presidential Memorandum directing the EPA to reconsider the waiver.[16][29] In the initial denial, EPA Administrator Stephen L. Johnson stated the Clean Air Act was not "intended to allow California to promulgate state standards for emissions from new motor vehicles designed to address global climate change problems" and further, that he did not believe "the effects of climate change in California are compelling and extraordinary compared to the effects in the rest of the country."[30] Johnson's successor, Lisa P. Jackson, signed the waiver overturning Johnson's denial, writing that "EPA must grant California a waiver if California determines that its standards are, in the aggregate, at least as protective of the public health and welfare as applicable Federal standards." Jackson also noted that in the history of the waiver process, over 50 waivers had been granted and only one had been fully denied, namely the March 2008 denial of the GHG emissions regulation.[31]

CARB decided to adopt regulation of GHG emissions under Executive Order G-05-061, which provided phase-in targets for fleet average GHG emissions in CO
₂-equivalent grams per mile starting with the 2009 model year.[32] The calculation of CO
₂-equivalent emissions was based on contributions from four different chemicals: CO
₂, N
₂O, CH
₄, and air conditioning refrigerants.

The emissions in g/mi CO
₂-equivalent are calculated according to the formula ${\displaystyle CO_{2}^{\mathrm {equivalent} }=CO_{2}+296\times N_{2}O+23\times CH_{4}-AC^{\mathrm {direct} }-AC^{\mathrm {indirect} }}$, which has two terms for direct and indirect emissions allowances of air conditioning refrigerants, depending on the refrigerant used, such as HFC134a, and the system design. Vehicles powered by alternative fuels use a slightly modified formula, ${\displaystyle CO_{2}^{\mathrm {equivalent} }=(CO_{2}+AC^{\mathrm {indirect} })\times F+296\times N_{2}O+23\times CH_{4}+AC^{\mathrm {direct} }}$, where ${\displaystyle F}$ is a fuel adjustment factor depending on the alternative fuel used (1.03 for natural gas, 0.89 for LPG, and 0.74 for E85). ZEVs are also required to calculate GHG as the processes to generate the energy (or fuel) used also produce GHG. For ZEVs, ${\displaystyle CO_{2}^{\mathrm {equivalent} }=U+AC^{\mathrm {direct} }}$, where ${\displaystyle U}$ is the upstream emissions factor (130 g/mi for battery electric vehicles, 210 for hydrogen/fuel cell, and 290 for hydrogen/internal combustion).[32] Direct CO
₂ emissions could be calculated in a relatively straightforward fashion based on fuel consumption.[33] Manufacturers that do not wish to measure N
₂O emissions may assume a value of 0.006 g/mi.[32] An update was issued in 2010 which allowed manufacturers to calculate GHG emissions using CAFE data; for conventionally powered vehicles, the contribution from the nitrous oxide and methane terms could be assumed to be 1.9 g/mi.[34]

CARB voted unanimously in March 2017 to require automakers to average 54.5 mpg for new cars in 2025.[35]

Section 177 states:
 •   blue=LEV only
 •   green=LEV+ZEV
 •   red=LEV repealed

Because California had emissions regulations prior to the 1977 Clean Air Act, under Section 177 of that bill,[39] other states may adopt the more stringent California emissions regulations as an alternative to Federal standards. Thirteen other states and the District of Columbia have chosen to do so, and ten of those have additionally adopted the California Zero-Emission Vehicle regulations.[36][37][40]

Arizona and New Mexico had previously adopted California LEV regulations under Section 177, but later repealed those states' clean car standards in 2012[41] and 2013,[42] respectively.[43]

In Canada, the province of Quebec adopted CARB standards effective in 2010.[44] CARB and the Government of Canada entered into a Memorandum of Understanding in June 2019 to cooperate on greenhouse gas emissions mitigation.[45]

The CARB Zero-Emission Vehicle (ZEV) program was enacted by the California government to promote the use of zero emission vehicles.[46] The program goal is to reduce the pervasive air pollution affecting the main metropolitan areas in the state, particularly in Los Angeles, where prolonged pollution episodes are frequent. The California ZEV rule was first adopted by CARB as part of the 1990 Low-Emission Vehicle (LEV I) Program.[13] The focus of the 1990 rules (ZEV-90) was to meet air quality standards for ozone rather than the reduction of greenhouse gas (GHG) emissions.[47]^:5

Under LEV II in 1999, the ZEV regulations were moved to a separate section (13 CCR § 1962) and the requirements for ZEVs as a percentage of fleet sales was made more formal. Executive Order S-03-05 (2005) and Assembly Bills 1493 (2002) and 32 (2006) prompted CARB to reevaluate the ZEV program as last amended in 1996, which had been primarily concerned with reducing emissions of smog-forming pollutants.[47] By the time AB 32 passed in 2006, vehicles complying with PZEV and AT PZEV standards had become commercially successful, and the ZEV program could then shift towards reducing both smog-forming compounds and greenhouse gases.[47]

LEV I defined a ZEV as one that produces "zero emissions of any criteria pollutants under any and all possible operational modes and conditions." A vehicle could still qualify as a ZEV with a fuel-fired heater, as long as the heater was unable to be operated at ambient temperatures above 40 °F (4 °C) and did not have any evaporative emissions.[14]^:2–6;2–7 Under LEV II (ZEV-99), the ZEV definition was updated to include precursor pollutants, but did not consider upstream emissions from power plants.[48]^:C-1

The ZEV regulation has evolved and been modified several times since 1990, and several new partial or low-emission categories were created and defined,[49][50][51][52] including the introduction of PZEV and AT PZEV categories in ZEV-99.[48]^:B-1;B-2

• PZEV (Partial Zero Emission Vehicle): Meets SULEV tailpipe standards, has a 15-year / 150,000 mile warranty, and zero evaporative emissions. These vehicles are 80% cleaner than the average 2002 model year car.
• AT PZEV (Advanced Technology PZEV): These are advanced technology vehicles that meet PZEV standards and include ZEV enabling technology, typically hybrid electric vehicles (HEV). They are 80% cleaner than the average 2002 model year car.
• ZEV (Zero Emission Vehicle): Zero tailpipe emissions, and 98% cleaner than the average new 2003 model year vehicle.

Under ZEV-90, CARB classified manufacturers according to the average sales per year between 1989 and 1993; small volume manufacturers were those that sold 3,000 or fewer new vehicles per year; intermediate volume manufacturers sold between 3,001 and 35,000; and large volume manufacturers sold more than 35,000 per year.[14]^:2–3 For large volume manufacturers, CARB required that 2% of 1998 to 2000 model year vehicles sold were ZEVs, ramping up to 5% ZEVs by 2001 and 10% ZEVs in 2003 and beyond. Intermediate volume manufacturers were not required to meet the goals until 2003, and small volume manufacturers were exempted. These percentages were calculated based on total production of passenger cars and light-duty trucks with a loaded vehicle weight (LVW) less than 3,750 lb (1,700 kg).[14]^{:3–22 to 3–24} [53]

The LEV I rules also introduced the concept of emission credits. Under LEV I, the vehicle fleet average emissions rate of non-methane organic gases (NMOG) produced by a manufacturer was required to meet increasingly stringent requirements starting in 1994.[14]^:3–18 The calculation of fleet average NMOG emissions was based on a weighted sum of vehicle NMOG emissions, based on the number sold and type of certification (i.e., TLEV, LEV, ULEV, etc.), divided by the total number of vehicles produced, including ZEVs.[14]^:3–20 Manufacturers whose fleet average NMOG emissions met or exceeded the NMOG emissions goal would be subjected to civil penalties; those which fell below the goal would receive credits, which could then be marketed to other manufacturers.[14]^:3–24

The 1996 amendments to the ZEV regulations in LEV I (ZEV-96) introduced credits where a ZEV could be counted more than once based on vehicle range or battery specific energy to encourage deployment of ZEVs prior to 2003.[54]^:3–4

Under LEV II/ZEV-99, the PZEV and AT PZEV categories were introduced, and the percentage of ZEVs sold by a manufacturer could be partially met by the sales of PZEV and AT PZEVs.[48]^:C-2 If a vehicle met PZEV criteria, it qualified for a credit equal to 0.2 of one ZEV for the purposes of calculating that manufacturer's ZEV production.[48]^:C-6 AT PZEVs capable of traveling with zero emissions for a limited range were allowed additional credit if the urban all-electric range was at least ten miles.[48]^:C-7 ZEVs that were introduced prior to 2003 received a multiplier, with a value ranging up to 10× a single ZEV depending on the all-electric range and fast-charging capability.[48]^:C-11;C-12

In March 1996, ZEV-96 eliminated the ZEV ramp-up planned to start in 1998, but the goal of 10% ZEVs by 2003 was retained, with credits granted for sales of partial ZEVs (PZEVs).[54][49] According to comment responses, CARB determined that advanced batteries would not be ready in time to meet the ZEV requirements until at least 2003.[56]^:6–7

GM EV1

In conjunction with relaxing the requirements in ZEV-96, CARB signed memoranda of agreement (MOAs) with the seven large scale manufacturers to begin rolling out demonstration fleets of ZEVs with limited public availability in the near term. The GM EV1 was the first battery electric vehicle (BEV) offered to the public, in partial fulfillment of the agreement with CARB. The EV1 was available only through a US$399 (equivalent to $650 in 2019)/month lease starting in December 1996; the initial markets were South Coast, San Diego, and Arizona, and expanded to Sacramento and the Bay Area. GM also offered an electric S-10 pickup truck to fleet operators.[55]

In 1997, Honda (EV Plus, May 1997), Toyota (RAV4 EV, October 1997), and Chrysler (EPIC, 1997) followed suit. Ford also introduced the Ranger EV for the 1998 model year, and Nissan stated they planned to offer the Altra in the 1998 model year as well to fulfill the MOA. As an acceptable alternative, Mazda stated they would purchase ZEV credits from Ford.[55]^:7–10

The Low-Emission Vehicle Program is currently under revision to define modified ZEV regulations for 2015 models.[49][57][58] CARB estimates the ZEV program will result in 15% ZEV sales by 2025. The share remained at 3% between 2014 and 2016. Battery vehicles receive 3 or 4 credits, while fuel cell cars receive 9. As of 2016, a credit has a market value of $3-4,000, and some automakers have more credits than required.[59][60]

The Low-Carbon Fuel Standard (LCFS) requires oil refineries and distributors to ensure that the mix of fuel they sell in the Californian market meets the established declining targets for greenhouse gas emissions measured in CO2-equivalent grams per unit of fuel energy sold for transport purposes. The 2007 Governor's LCFS directive calls for a reduction of at least 10% in the carbon intensity of California's transportation fuels by 2020. These reductions include not only tailpipe emissions but also all other associated emissions from production, distribution and use of transport fuels within the state. Therefore, California LCFS considers the fuel's full life cycle, also known as the "well to wheels" or "seed to wheels" efficiency of transport fuels.[13][61] The standard is aimed to reduce the state’s dependence on petroleum, create a market for clean transportation technology, and stimulate the production and use of alternative, low-carbon fuels in California.[62]

On April 23, 2009, CARB approved the specific rules for the LCFS that will go into effect in January 2011.[63][64] The rule proposal prepared by its technical staff was approved by a 9-1 vote, to set the 2020 maximum carbon intensity reference value to 86 grams of carbon dioxide released per megajoule of energy produced.[62][65]

The PHEV Research Center was launched with funding from the California Air Resources Board.

Under the Innovative Clean Transit (formerly known as the Advanced Clean Transit) regulation adopted in December 2018, public transportation agencies in California will gradually transition to a zero-emission bus fleet by 2040.[66] Large transit agencies (defined as those operating more than 65 buses in the San Joaquin Valley Air Basin or South Coast Air Quality Management District, or those operating more than 100 buses elsewhere with populations greater than 200,000) are required to have 25% of new bus purchases as zero-emission buses (ZEBs) starting in 2023, 50% of new purchases as ZEBs starting in 2026, and 100% of new purchases as ZEBs starting in 2029. Small transit agencies are required to make 25% of new purchases as ZEBs in 2026 and 100% of new purchases as ZEBs in 2029+. Per the regulation, ZEBs are defined to include battery electric buses and fuel cell buses, but do not include electric trolleybuses which draw power from overhead lines.[67] The Antelope Valley Transit Authority has set a goal to be the first all-electric fleet by the end of 2018, ahead of the tightened regulations.[68]