The pollution that contributes to San Diego's occasional brown mantle of smog is diminishing, but at a slower rate than environmental officials had hoped, according to the annual report released Wednesday by the San Diego County Air Pollution Control District.
Daily emissions of reactive hydrocarbons--which combine with oxides of nitrogen to produce smog--averaged five tons a day less in 1985 than in 1984, the report said. But the daily level of 230 tons exceeded the district's earlier projections for 1985 by 32.4 tons.
Richard Sommerville, the county's air pollution control officer, blamed the shortfall on an unexpectedly large increase in motor vehicle emissions, reduced effectiveness of the state's automobile inspection program, and a lag in the development of anti-pollution technologies.
"The control strategy is clearly being affected by delays in technology development and program revisions in the case of the inspection and maintenance program," he said. " . . . Right now, in terms of whether we will attain the (federal) standard in 1987 as required by the Clean Air Act, it's a wait and see."
Under the Clean Air Act, San Diego must reduce its hydrocarbon emissions to 212 tons a day or less. Like other cities, it must show each year that it is making "reasonable progress" toward that goal, among others. So it publishes an annual report for the federal Environmental Protection Agency.
San Diego County air falls within the federal standards for lead, nitrogen dioxide, sulfur dioxide and carbon dioxide, according to the district. Because ozone, the main constituent of smog, is the largest pollution problem in the county, the air-pollution control strategy and annual report focus on cutting hydrocarbon emissions.
Out of the report, Sommerville picked two trends he saw as significant.
First, he said, the statistics illustrate a steady improvement in the reduction of hydrocarbon emissions since 1978. That year, emissions exceeded the federal standard on 80 days; last year, they exceeded the standard on 55 days.
On 19 of those days, the sources of pollution were local, said Sommerville. That means, he said, that on 65% of the smoggy days some or all of the excess pollution came from sources in Los Angeles and its surrounding South Coast air basin.
Secondly, Sommerville said that delays in expected reformulations of paints, glazes and other "architectural coatings" are impeding the county's ability to reduce hydrocarbon emissions. There have also been delays in improving aerospace coatings, another source of hydrocarbon emissions.
He also said that the state's decision to require biannual auto inspections, rather than annual checks, has meant that reductions in pollution from cars have been less than anticipated in 1982.
As in the past, the report indicates that Alpine remains one of the communities most seriously victimized by air pollution. Sommerville said Alpine is smoggy because it is on an elevated site just beneath the usual inversion layer and downwind from major sources of pollution.
"It's downwind from everything and it's right up near the top of the inversion, where everything is trapped . . . and the chemicals are working away like crazy," Sommerville said. "And there sits poor Alpine. So basically, the problem with Alpine is its location, very little else."