Under the Clean Air Act Amendments of 1990, California is the only state in the US permitted to set its own emissions standards. However, once the state’s emissions strategy is finalised and approved by the Environmental Protection Agency (EPA), other states can ‘opt into’ the scheme. Twelve states have agreed to follow this course of action.

The California Air Resources Board (CARB) has identified a number of measures designed to fill in a three year loophole from 2004 to 2007 between two sets of emissions legislation.

“For over a decade, Americans have breathed unnecessarily high levels of toxic diesel pollution, thanks to the diesel engine makers’ refusal to clean up their products,” said Richard Kassel, the Natural Resources Defence Council’s (NRDC) Senior Attorney, and co-ordinator of the organisation’s Dump Dirty Diesels Campaign. “Thanks to ground-breaking leadership by California and other states in every region of the country, loopholes that would allow this situation to continue will soon be closed.”

According to the NRDC, in 1999, seven diesel engine manufacturers, including Navistar International and Volvo, agreed to pay the largest air pollution fine in history, rather than face prosecution for their practice of building engines met EPA emission standards in laboratory tests, whilst emitting as much as three times the amount of pollution on the open road. The companies agreed that their engines should pass a series of supplemental emissions tests between 2002 and 2004. However, this leaves a gap of three years before the EPA’s industry-wide emissions rules come into effect in 2007.

“The companies’ slow steps towards compliance demonstrate clearly that they would rather fight than switch,” said Kassel. “The states will be fighting back with a great complement to ongoing EPA enforcement efforts, and the result will be cleaner diesel engines on the roads, in every region of the country.”

As well as the stringent standards for diesel-fuelled engines, CARB also plan to establish particulate trap retrofit requirements for existing engines, evaluate alternatives for diesel, and to reduce the sulphur content of the fuel. The twelve states which will participate in California’s diesel emissions programme are: Connecticut, Delaware Georgia, Maine, Massachusetts, Nevada, New Hampshire, New Jersey, New York, North Carolina, Rhode Island, Texas, and Vermont. The co-ordination of the large number of states joining the new pollution standard has been assisted by the State and Territorial Air Pollution Programme Administrators, and the Association of Local Air Pollution Control Officials (STAPPA/ALAPCO).

Meanwhile, California is also celebrating its cleanest-ever gasoline-powered vehicle. The Nissan Sentra CA (Clean Air), certified as the cleanest gasoline-fuelled car in the world, has received the Governor’s Environmental and Economic Leadership Award from the California EPA.

Currently only available in California because of the ease of access to low-sulphur fuel within the state, the Sentra CA is also the only gasoline-fuelled car to be certified to the CARB’s partial Zero Emission Vehicle credits.

“California’s leadership in reducing emissions from gasoline-powered automobiles is enjoying unparalleled success so far with the development of the Nissan Sentra CA,” said CARB Chairman, Dr Alan Lloyd. “To be able to market a vehicle with such dramatically reduced emission characteristics would have been unimaginable a decade ago. This demonstrates that automotive ingenuity combined with good public policy can produce stunning environmental results.”

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