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How LA Might Meet Smog Standards By 2010

UC Riverside Study Shows Accelerated Introduction of Super-Clean Cars Will Help Los Angeles Meet Federal Smog Standards By 2010

(September 23, 2003)

RIVERSIDE, Calif. — Sept. 23, 2003 — ( — The Los Angeles metropolitan area, characterized by some of the dirtiest air in the nation, could achieve federal air quality goals for smog more rapidly if the use of super-clean vehicles, available in showrooms today, is aggressively implemented, according to study results released today by the University of California, Riverside.

The “Study of Extremely Low Emission Vehicles” (SELEV) was conducted over the past three years by the UC Riverside Bourns College of Engineering’s Center for Environmental Research and Technology (CE-CERT). The study examined emissions from vehicles that meet the California Air Resources Board’s standards for ultra-low emission vehicles (ULEV), super-ultra-low emission vehicles (SULEV), and partial zero-emission vehicles (PZEV).

The study’s final results found that the greater use of the best existing, proven, gasoline engine and auto emission control technology could enable the Los Angeles air basin to reach 2010 ozone — commonly referred to as smog — attainment goals.

Atmospheric modeling conducted as part of the CE-CERT study showed that if it was possible by 2010 for all passenger vehicles to be less than 15 years old, and for all cars sold in 2004 and later to meet at least the current California SULEV standard, then the federal smog standard could be met by 2010. “Achieving this scenario may not be realistic, but the important point is that the technology is here today to do it,” Norbeck said.

The study was sponsored by the U.S. Environmental Protection Agency, the California Air Resources Board (CARB), Honda R&D Americas, Inc., ChevronTexaco North America Products, and the Manufacturers of Emission Controls Association.

"There is no such thing as a magic bullet in solving the air pollution problem,” said Dr. Joseph Norbeck, CE-CERT director. “But we believe we’ve found a viable tool with the emerging crop of cars that meet California’s most stringent emissions standards. Meeting the Los Angeles metropolitan area’s 2010 air quality goals can be helped with aggressive implementation of existing technologies.”

"This study illustrates that light-duty passenger automobiles will soon be taken off the 'most-wanted' list of air pollution sources," said Norbeck. “Our results show that replacing a gasoline powered vehicle in Los Angeles that is 15 years old or older reduces the smog-forming emissions by more than 97 percent.

“The impressive thing about these findings is that the technology and fuels that were developed for these clean cars to meet the California air standards will, within a few years, find themselves in the rest of the nation’s fleet and then the rest of the world’s fleet. The recipe for attacking smog is clean vehicles aided by clean fuels. If the clean fuel is available we’ll soon find that these cars will be able to help solve air quality problems in cities in China, India, Egypt and other air-quality challenged countries.”

The study evaluated tailpipe emissions from ULEV, SULEV and PZEV vehicles under real-world conditions to meet California’s strict emissions standards. Researchers drove the test vehicles in typical Southern California traffic in all types of weather conditions.

“We drove these cars the way most Southern Californians drive theirs — in stop-and-go rush-hour traffic on high-speed freeways, in the heat and rain — and they were found to maintain near-zero emissions,” said Norbeck. “We found that the cars’ emissions were below the CARB emissions standards. The in-use deterioration of the emissions control systems was extremely low, meaning we can anticipate these cars to go well into the 100,000 mile range with consistent air quality benefits.”

The CE-CERT work on the SELEV program was a continuation of research — results of which were announced in September 2002 ( — that found advanced technology could all but eliminate air pollution from gasoline-fueled vehicles. The current study expanded the vehicle testing program and looked at the atmospheric improvements achievable with the new technology.

These new, super-clean vehicles use improved fuel management and catalyst technologies as well as new technology that virtually eliminates evaporative emissions. The technologies also allow cars and light trucks to be produced at costs similar to those of current vehicles.

Differing types of SULEV and PZEV technology are available today in thirteen models of cars from various manufacturers certified by CARB. Honda, Ford, Toyota, BMW, Volvo and several other automakers provide models that include the SULEV and PZEV technology.


In June 2000, CE-CERT established the SELEV program in partnership with industry and government agencies with the purpose of understanding, via direct measurements and modeling, the impact that new-generation vehicles with extremely low emissions have on overall air quality.

CE-CERT has successfully developed the measurement technology to test emissions at lower levels, most importantly vehicles that meet the state’s stringent SULEV and PZEV standards. These vehicles must meet the increasingly stringent requirements for volatile organic compounds (VOC), oxides of nitrogen (NOx), and carbon monoxide (CO) on emissions certification tests. Technology has also been developed to measure the emissions of these vehicles under real-world conditions, while they are being driven on the road.

VOCs are of concern because of their role in the formation of ozone, which has adverse health effects. NOx, which is formed in the combustion chamber of the engine, is an irritant to the lungs and can aggravate respiratory problems. It is also a precursor to the production of ozone and very fine particulate matter in the atmosphere. CO, a colorless, odorless, and poisonous gas, results from incomplete combustion of fuel and is emitted directly from vehicle tailpipes. Its entry into the bloodstream through the lungs can hinder the blood's capacity to carry oxygen to organs and tissues. CE-CERTs results showed the emissions of these pollutants were essentially reduced to zero.

CE-CERT was established in 1992 as a model for partnerships among industry, government, and academia. CE-CERT's goals are to become a recognized leader in environmental education, a collaborator with industry and government to improve the technical basis for regulations and policy, a creative source of new technology, and a contributor to a better understanding of the environment. CE-CERT is committed to furthering education and research for the next generation of engineers. Its students receive an excellent education and unprecedented opportunities to be intimately involved in the research enterprise.


The University of California, Riverside ( is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 21,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion.

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