More than 300 researchers from around the world began packing their gear and heading home Friday after a comprehensive $10-million air pollution study of the Los Angeles Basin was postponed for three weeks because the air is not smoggy enough.
Unusually favorable weather conditions have reduced smog levels to such an extent that scientists said it would be better to wait until the air gets dirtier.
"I hate to complain about nice weather," said researcher Barbara Turpin of the Oregon Graduate Center in Beaverton, Ore. "I went to school down here and can remember the summers being awfully hot and smoggy. Now I return to sample the smog and it's not there. It's sort of ironic."
The study, the most extensive in 15 years, is expected to provide new insights into how pollutants behave in the air and eventually could lead to a new generation of air pollution control strategies.
The decision to postpone the study until Aug. 20 was made Friday after a telephone conference call among representatives of participating government agencies, academic institutions and businesses that are financing the research.
The 51 teams of scientists have been planning the experiments for two years.
When the Southern California Air Quality Study began last month, sponsors said the Los Angeles Basin was chosen because it had the most intractable air pollution problem in the country. But, cool, moist marine air from the Gulf of Alaska and a higher-than-normal inversion layer sent the scientists packing.
"If this July was a normal July we probably would have achieved all of our goals. But the air has been much more unstable, inversions higher and weaker, winds brisker, the cloudiness has been more frequent and you don't have a lot of sunshine," said Arthur Davidson, head of air quality and meteorology with the South Coast Air Quality Management District.
"Rather than stand around and wait for high ozone conditions . . . the decision was to stand down right now, close up shop and come back Aug. 20," he said.
For some, however, the delay will mean the end of their participation. Regina Hitzenberger of the University of Vienna in Austria said she will be unable to return in August because of previously scheduled commitments and limited research funds.
"For me it's the end of the study, unfortunately," she said. "I think it's one of the things you have to expect in a field study. You cannot plan the weather beforehand. But I have quite a lot of good data and will be able to do something with them and I hope others from the study will be able to use my data," she said. Hitzenberger was studying the overall effect of particulate matter on reduced visibility.
Not Considered Serious
The delay is not expected to seriously impair the research effort. Susanne Hering, coordinator of field experiments, said she expects at least three-fourths of the researchers to return. Moreover, the data collected by those who do return will be available to all participants.
Researchers had hoped to carry out experiments on at least 10 days of typical smog levels, but found only five since the study began June 15. Despite the setback, ARB research director John Holmes said, "We're confident that all of the researchers participating in the study will get all the smog data they need by the end of the summer," he said.
So far this year, there have been Stage I smog alerts in the basin on only 22 days, compared to 38 by this time last year and 53 in 1985. A Stage I alert is called when pollution levels reach .20 parts per million for one hour. Researchers were looking for days when levels reached .24 parts per million.
The 10-week study was to have been divided into two phases. The first, from June 15 to July 26, was designed to sample typical smoggy summer air. This phase is now scheduled to resume Aug. 20 and end Sept. 12. The second half, during what is hoped will be typical winter conditions, is scheduled for Nov. 15 to Dec. 15.
Participants in the study, led by the California Air Resources Board, include the U.S. Environmental Protection Agency, the South Coast Air Quality Management District, Ford Motor Co., General Motors Research Laboratories, Motor Vehicle Manufacturers Assn., Southern California Edison, and the Western Oil and Gas Assn., as well as researchers from academic institutions.
It has been 14 years since the last comprehensive study. Known as the Aerosol Characterization Experiment, that 1973 study formed the scientific underpinnings of existing air pollution controls.