Dirty air gives gasohol a boost. Colorado to require use of gas substitute this winter

Fill'er up - with alcohol. This refrain, heard at some gas stations in the fuel-stingy days of the 1970s, may soon be echoing throughout the United States. This time around, however, the interest isn't being driven so much by concern about US dependence on foreign oil as by the need to reduce air pollution.

The befouling of skies over much of urban America is prompting governments to consider wider use of alcohol fuels - principally methanol, usually processed from natural gas or coal; and ethanol, commonly made from grain. While plenty of critics still consider the cleaner-burning fuels impractical for use on a broad scale, efforts are under way to put more alcohol in gas tanks:

At least 16 bills have been introduced in Congress to spur increased alcohol fuel use, including several that would mandate the selling of ethanol nationally.

Colorado will be closely watched this January when it kicks off the country's first program mandating the use of high-oxygen fuels as a way to reduce wintertime levels of carbon monoxide. Two blends will be available: ethanol and MTBE, a petroleum derivative.

California is pushing ahead with an ambitious program to promote the use of nearly pure methanol. The state hopes to replace 10 percent of its gasoline with the fuel by the year 2000.

There's a bit of d'ej`a vu about all this. Back in the oil crisis days, gasoline-alcohol blends - dubbed gasohol - were touted as a way to help insulate the country from Arab oil politics. The idea caught on to a degree: In some Midwestern states, gasoline mixed with 10 percent ethanol captured up to 30 percent of the market.

Today some 8 billion gallons of ethanol-blended gasoline is sold annually - about 8 percent of the total US market. Even so, interest in the fuels has waned of late in the face of declining oil prices.

That may now be changing. Enduring concern about energy security is one reason. Basic farm-belt economics is another. Many see wider use of ethanol as a way to reduce grain surpluses and agriculture subsidies. Several of the ethanol bills in Congress are being pushed by farm-belt lawmakers. A primary factor, though, is the environment. The US Environmental Protection Agency has said at least 76 cities will not meet its clean-air standards set for Jan. 1 and will be subject to a cutoff of certain federal funds.

While alcohol supporters concede they will not help cities clean up skies soon, they nonetheless see the fuels as a key weapon in the long-range fight against smog - and one less painful than enforcing draconian measures such as restricted car use.

``We think they can have a very big impact,'' says C. Boyden Gray, counsel to the President's Task Force on Regulatory Relief, which has been promoting use of alternative fuels. In a recent report, the task force said relatively pure methanol (85 percent) could cut vehicle emissions of ozone-forming hydrocarbons by 20 to 50 percent.

Colorado officials are hoping for a reduction of up to 16 percent in carbon monoxide emissions as a result of their blended ethanol and MTBE program, which will be enforced in winter months and in cities.

California is spending $1.7 million to help public agencies finance 5,000 flexible-fuel vehicles that burn either gasoline, pure methanol, or a mixture. ARCO plans to market methanol at 25 of its stations by next October.

But alcohol fuels have their problems. Ethanol made from grain is readily accessible, but not economical. It is currently competitive with traditional fuels only because producers get tax breaks.

Ethanol and methanol yield fewer miles to the gallon than straight gasoline. While methanol is now cheaper than gas, some energy analysts believe a surge in demand would drive up its price.

Moreover, they argue that the biggest supplies of inexpensive natural gas and methane, from which methanol would be produced, lies in the Middle East, a factor that could heighten the US dependence on the region. Methanol made from domestic coal, the same analysts contend, is too expensive to compete with gasoline at current prices.

Alcohol blends evaporate more readily than gasoline, creating some pollution problems in their own right. Because blends tend to be more volatile, they can also cause what Robert Dewey of the Center for Auto Safety calls ``driveability'' problems - more stalling, for instance.

Cars that burn purer forms of methanol have to be equipped with special corrosion-resistant materials, and some companies are starting to make them.

Still, even with these obstacles, alcohol fuels seem ``better equipped now for a resurgence than they ever have been,'' says William Holmberg, an energy consultant.