Ventura County must find ways to cut air pollution by another 40% to meet minimum federal standards, according to information derived from unprecedented computer modeling conducted by the Environmental Protection Agency.
The county failed to meet the standards on one out of every six days in 1988, officials said.
Richard Baldwin, county air pollution control officer, said his agency is considering a broad range of pollution-reducing measures, including requiring factories and other industrial sources of pollution to modify their equipment. At present, only new industry is required to install what is called the "best available control technology."
Emissions limits also might be lowered for new industry.
Other possible measures cited by Baldwin include:
Reducing the use of certain pesticides.
Cutting emissions from boats that ferry supplies to offshore oil platforms.
Requiring clean fuels, such as compressed natural gas or electricity, for automotive fleets with 15 or more vehicles.
Requiring methane gas recovery systems for all landfills.
Imposing more restrictions on dry cleaners.
Imposing more restrictions on the kinds of coatings and paints used on houses, used cars and boats.
The EPA performed the computer studies as part of a settlement in a lawsuit against it and the county Air Pollution Control District.
Citizens to Preserve the Ojai, an environmentalist group, sued over the district's 1982 Air Quality Management Plan, which failed to show means by which the county could meet clean air standards.
The settlement last March set a September, 1990, deadline for the county to draft stringent new rules--a process that required data available only from elaborate computer modeling.
Without that data, the district could make only educated guesses on how emissions added to weather conditions to produce the daily pollution picture.
"We come up with a grand scheme of things to do to reduce emissions," Baldwin said, "but we don't know what that will do to air quality until we put it into the model."
If the county does not draft effective rules, the EPA will, and Baldwin said he fears it would do so with measures as drastic as gas rationing or restrictions on the days one may drive a car.
"The EPA might say no driving on Monday if your license ends in A," Baldwin said. "Nobody wants to see those things, and I'm working hard to avoid it."
In computer modeling, scientists feed into the system information on emissions, weather patterns and air flows from both on and offshore, said John Vimont, a regional meteorologist in the EPA's San Francisco office. The model also considers existing population, planned growth and future emission reductions from pollution-control programs now in place.
Using software developed over the last 15 years, the computer follows the movement of air through a region and predicts how it will react with pollutants.
After several runs, the model pegged the clean-air target at a 40% reduction of both oxides of nitrogen and reactive organic compounds, the major components of smog.
"It is a planning tool," Baldwin said, adding that the error factor is as high as plus or minus 30%. "But it tells you if you're going in the right direction. It's an extremely complex science to try to link emissions and meteorology to air quality levels."
"It gives us a ballpark figure," Vimont said.
Motor vehicles produce the lion's share of both sets of emissions in the county, according to Ventura County district figures. The oil industry and power plants are the next largest contributors, followed by other industrial sources and agriculture.