U.S. Clean Fuel Programs Have Helped to Clear the Air

Changes in gasoline composition to comply with federal clean fuel programs between 1995 and 2005 resulted in emission reductions that were often "substantially greater than regulatory requirements," according to a new analysis issued today by the U.S. Environmental Protection Agency.

The EPA adopted clean fuel programs for gasoline as a result of the Clean Air Act of 1990.

In 1995, the agency implemented the reformulated gasoline program, designed to reduce emissions of smog-forming volatile organic compounds, VOCs, and oxides of nitrogen, NOx, as well as air toxics such as benzene and formaldehyde from motor vehicles.

Fueling in Florida (Photo by Jem Ross)

At the same time, EPA began an anti-dumping program, to protect the emission qualities of conventional gasoline. In 2000, credit for early gasoline sulfur reduction was provided by the EPA's Tier 2 gasoline sulfur program.

These clean fuel programs required gasoline refiners and importers to analyze gasoline, measure certain emission-related parameters, and submit the data to the EPA.

Analysis of this data by the EPA's Office of Transportation and Air Quality shows that average annual sulfur content in all gasoline dropped from about 300 parts per million in 1997 to about 90 ppm in 2005.

Early decreases in overall gasoline sulfur content were primarily due to decreases in reformulated gasoline sulfur content linked to the phase-in of increasingly stringent reformulated gasoline NOx emission performance standards, the EPA says.

These NOx emission performance standards did not mandate sulfur reduction, but lowering sulfur content was one of several changes important to meeting the reformulated gasoline NOx standards.

Reformulated gasoline exceeded NOx performance standards during both Phase I (1998-1999) and Phase II (2000 and beyond), the analysis found.

On average, Phase I reformulated gasoline complied with Phase II standards, and toxic performance still improved with the transition to Phase II standards.

In conventional gasoline too, NOx and toxics emissions decreased.

Between 1998 and 2005, the summer NOx emissions of conventional gasoline were reduced by 5.7 percent, while summer exhaust toxics were reduced by 4.7 percent, the EPA analysis shows.

The Clean Air Act required that reformulated gasoline contain two percent oxygen by weight to help the gas burn cleaner. MTBE and ethanol were the primary oxygenates used.

Between 1996 and 2005, ethanol increasingly replaced MTBE, which was found to pollute groundwater when it leaked from underground gasoline storage tanks. Most states now have banned MTBE or are considering bans.

In the summer of 1996, about 11 percent of the reformulated gasoline sold contained ethanol while the reset contained MTBE.

By the summer of 2005, the ethanol share increased to about 53 percent, with corresponding decreases in MTBE, the analysis shows.

Congress mandated the repeal of the reformulated gasoline oxygen content requirement in the Energy Policy Act of 2005, enacted August 8, 2005.

Triple biofuels dispenser in Santa Fe, New Mexico (Photo courtesy Renewable Energy Partners of New Mexico)

The American Petroleum Institute, which represents the fuel supply industry, says there are numerous challenges to adding a large quantity of ethanol into the reformulated gasoline pool.

The ethanol must be moved from the Midwest, where it is produced, to consumers in Texas and the East Coast and there have been issues with the availability of ethanol storage and transportation infrastructure.

Adding ethanol tanks and blending equipment at terminals has posed challenges, and so has the conversion of retail tanks to ethanol service.

Still, all this work has begun to clear the air.

The American Lung Association took notice of the cleaner air in its 2007 annual air quality report card, issued in May, saying that smog decreased nationwide from peaks reported in 2002.

"Ozone pollution dropped thanks to a late 1990s requirement to clean up emissions of the raw ingredients of smog, as well as cooler summers in 2003 and 2004," the Lung Association said. "In the West, particularly in California, aggressive measures to reduce emissions from a wide range of air pollution sources - cars, trucks, and other mobile sources - contributed to fewer high ozone days."

American Lung Association Chair Terri Weaver, PhD, RN, says that while the air is cleaner, more work still needs to be done.

"The good news is that there's less ozone everywhere. Yet, we remain concerned because the science shows that millions are still at risk from ozone that exceeds acceptable levels," Weaver said. The association's 2007 report shows that one-third of the U.S. population still lives in areas with unhealthful levels of ground-level ozone, or smog.

The association is asking the EPA to protect public health by adopting a strong ozone standard at the most protective level staff and independent science experts recommended - 0.060 ppm.

"Breathing ozone smog threatens serious health risks, including new evidence that links it to premature death." Weaver said. "We're calling on EPA to set new standards for ozone at levels that would protect public health as the Clean Air Act requires."

Ozone smog can cause asthma attacks, coughing and wheezing, shortness of breath, chest pain when inhaling deeply. Breathing ozone smog threatens serious health risks, including new evidence that links it to premature death.

People most sensitive to ozone smog are children and teens, the elderly, people with asthma and other lung diseases and even healthy people who work or exercise outdoors.

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