CLEAN AIR: Officials think city can meet standards without gas additive.
By ROSEMARY SHINOHARA
Anchorage Daily News
(Published: April 21, 2003)
Ethanol is added to gasoline in Anchorage from November to March to reduce
the levels of carbon monoxide, a colorless, odorless, poisonous gas in car and
truck exhaust.
The city used to exceed federal clean air limits for CO regularly but has not
done so since 1996, said Steve Morris, quality supervisor.
The state gives Anchorage fuel dealers a 6-cent-per-gallon break on gasoline taxes for blending ethanol into the mix. If the state stops supporting the ethanol program, Anchorage residents could end up paying higher winter prices at the pump for it.
Or maybe Anchorage has cleaned up its air enough to skip ethanol. The state believes that's the case.
"We're safely on the good side of the standard," said Tom Chapple, state director of air and water quality. Otherwise, he said, state administrators wouldn't have written the subsidy out of the state's budget.
The requirement that vehicles registered in Anchorage pass emissions tests every other year does the most to cut CO pollution, and the ethanol program is the next most effective strategy. Using car engine heaters also helps. The city would keep the emissions tests and continue to encourage plugging in, whatever happens to ethanol.
Oxygenated gas, or gas laced with ethanol, provides roughly a 5 percent CO reduction, Morris said.
It results in cleaner-burning engines but affects only cars and trucks built before 1994, experts say. So every year, as Anchorage's vehicle fleet has gotten newer, the benefits of ethanol have diminished.
At a recent transportation meeting, Mayor George Wuerch suggested that instead of just eliminating ethanol, the state could give some of the money back to the city for another pollution control program: buying back old, polluting cars.
The standards call for carbon monoxide levels to remain at or below 9 parts per million on average over an eight-hour period every day. Anchorage tests CO at four sites: at the Seward Highway and Benson Boulevard next to Allen and Petersen Home Decorating Center; near Turnagain and West Northern Lights boulevards; near Jewel Lake Road and 88th Avenue; and near 16th Avenue and Garden Street in Airport Heights.
Anchorage air is allowed to reach pollution levels above the standard one day per year and still not be in violation.
With all of its current air-quality programs, the city now figures it has a 95 percent probability of avoiding violations, Morris said. Without ethanol, preliminary study shows Anchorage would still have a 90 percent likelihood of meeting the standards, Morris said.
A program to buy and destroy old clunkers, such as Wuerch proposed, would improve the air, though not enough to make up for ethanol, Morris said.
The level of CO in Anchorage air depends partly on weather. Emissions go up when it's colder. And temperature inversions trap pollutants near the ground. But on typical winter days, Anchorage's carbon monoxide levels reach only 2 to 3 parts per million, Morris said. And over several years, through warm and cold winters, the trend is good, he said.
When carbon monoxide levels rise above the federal standard, studies have shown that people with weakened hearts are in greater danger of angina or even being admitted to hospitals for congestive heart failure, Morris said.
The city's complete program to limit low carbon monoxide will probably not be approved by the federal Environmental Protection Agency until around the end of the year, Morris said. But sometime between now and November, when the dealers are supposed to resume use of ethanol, the city expects a decision on whether that's necessary.