SOUTHERN CALIFORNIA’S ENVIRONMENT At the Crossroads : HEALTH: PINPOINTING THE RISKS : Science Identifies No. 1 Peril: Breathing Southland’s Bad Air

Although cigarette smoke is far more deadly, air pollutants such as ozone and fine particulate matter are the greatest environmental health threats in Southern California.

Exposure to highly polluted air can cause immediate breathing difficulties as well as headaches and eye irritation. With years of exposure, the normal aging of the lungs may speed up. This may contribute to the development of disabling bronchitis and emphysema.

“The bottom line is that chronic exposure to (the chemicals in smog) contributes to an accelerated decline of lung function,” said Dr. Donald P. Tashkin, professor of medicine at the UCLA Medical Center. Tashkin said the decline was “independent of and additive to the effects of tobacco smoking.”

The increased risks of death associated with breathing polluted air are significantly higher than those associated with potential pollutants in drinking water, according to Dr. Malcolm C. Pike of the USC Medical Center in Los Angeles.

For example, in 1981, Pike and USC’s Dr. Brian E. Henderson estimated that Los Angeles air would cause an additional 1,000 lung cancer cases in 1 million lifelong residents over 70 years, an increase of slightly less than 0.1%.

By comparison, cancer standards for drinking water contaminants are usually set at a level below that which would be expected to cause one additional cancer case in 1 million people over a 70-year lifetime.

On the other hand, the estimated contribution of air pollution to cancer cases is dwarfed by other causes. According to Pike, smoking one-tenth of a cigarette a day poses a greater lung cancer risk than breathing Southern California air on a daily basis.

A Lifelong Effect

In total, about 24% of lifelong Los Angeles residents develop cancer by age 70, according to USC’s Dr. Ronald K. Ross. This includes 7.6% of men and 3.4% of women who develop lung cancer, primarily as a result of smoking. These rates are similar to those in other large urban areas.

Scientific evidence on the health effects of smog has been gathered from many sources, including animal and human tests of controlled levels of pollutants, the results of accidental human exposures, and comparisons of pollution levels and health data among different communities.

Research studies have focused attention on two pollutants--ozone and fine particulate matter--that contribute to making Southern California’s air pollution the worst in the nation.

The failure to meet state and federal clean air standards for these and other air pollutants results in additional days of discomfort, restricted activities, and missed work and school. The greatest impact is felt by children, the elderly, people with chronic lung diseases, athletes and workers who spend extended periods outside in the middle of the day.

Many UCLA researchers, including Tashkin, have been involved in an ongoing comparison of lung disease among thousands of adult residents of three Los Angeles County communities. The areas are Glendora, a high smog area, Long Beach, which has high levels of industrial air pollutants, and Lancaster, a less polluted area.

Study participants had their lung function checked in the mid to late 1970s. About half were tested again about five years later.

The researchers found that, on average, residents of Glendora and Long Beach lost lung function as measured by a key test--the ability to expire air within one second--at about twice the normal rate of 30 cubic centimeters a year. Lancaster residents lost only slightly more lung function than was predicted on the basis of increasing age.

Other researchers express reservations about the methodology of the UCLA study and point out that the findings have not been independently confirmed. But many, such as Michael Kleinman of UC Irvine, think that while the magnitude of the lung damage is uncertain, “in concept, the results are probably right.”

Another noteworthy study has been conducted at Loma Linda University. Researchers surveyed about 7,000 Seventh-day Adventist residents of California. They represent an almost entirely nondrinking, nonsmoking population with a wide geographic distribution, said Loma Linda’s David E. Abbey, one of the principal researchers

A 1977 survey found a “consistent and statistically significant” relationship between exposure to respirable particulates and ozone and significant respiratory symptoms, such as cough, shortness of breath and chronic sputum production, Abbey said.