Ill Winds? : Smog Chokes the Lungs and Burns the Eyes, but Experts Now to Study if the Harm Lasts

Expose a Southern Californian to a blast of unpolluted air and he’ll probably say it smells.

“We’ve done a lot of studies where we let people breathe absolutely purified air,” says Michael T. Kleinman, an air pollution researcher at UC Irvine. “The comment we get very frequently is, ‘This smells funny.’ People in Southern California are really not used to what clean air smells like.”

This peculiar comment on what life is like in the nation’s most polluted air basin was underscored less anecdotally this month, by a report that estimated the health costs of air pollution in the Los Angeles air basin to be at least $9.4 billion a year.

Unintentional Experiment

That study for the South Coast Air Quality Management District, as well as a report released Monday by the U.S. Office of Technology Assessment, make clear that the residents of polluted areas are participants in an unintentional experiment to determine the long-term effects of modern air pollution.

Scientists have been able to identify the short-term consequences of breathing too much ozone and microscopic chemical particles, but they have not done definitive studies looking for long-term lung damage.

The greatest impact of polluted air falls upon children because they play vigorously outside, the elderly because of the natural aging of their lungs, and outdoor workers because of extended periods outside in the middle of the day, experts agree. People with asthma or other lung problems also are susceptible, but tend to restrict their activities during peak pollution periods.

However, anyone can get symptoms of breathing too much smog if they do heavy exercise in it. The worst times are between about noon and 4 p.m. That is when levels are highest for the basin’s most pervasive pollutant, ozone, which comes from the action of sunlight on pollutants in the air. How serious the symptoms will be depends on a person’s location and individual sensitivity.

Significant Sensitivity

Research has found that a consistent 10% to 15% of the population, whether they are asthmatics or marathoners, show significant sensitivity to ozone, said John O’Neil, chief of the U.S. Environmental Protection Agency’s clinical research branch at Research Triangle Park, N.C.

These people temporarily lose 40% to 50% of their breathing capacity after two hours of alternating between 15-minute rest and exercise periods in ozone levels of 0.12 parts per million, research at the EPA lab has shown.

In 1988, air in the Los Angeles region exceeded this federal air quality standard on 176 days. Stage I ozone alerts, issued when the level reaches 0.20 ppm, have occurred on 26 days this year.

In the EPA tests, the loss of breathing capacity from ozone lasted for about an hour after the subjects were removed from the high-ozone environment, O’Neil said. Other symptoms during exposure included shortness of breath, chest pains, sore throat, coughing, eye irritation and headache.

Ozone forms in the air when sunlight hits hydrocarbons and nitrogen oxides emitted by cars and industry. Southern California’s sunny days are ideal for creating ozone, and the common summer weather pattern of vertically stagnant air layers keeps it from dissipating upward.

Role of Free Radicals

A highly reactive molecule made of three oxygen atoms, ozone undergoes chemical changes in lung fluid and releases an oxygen atom. This results in formation of small, highly reactive molecules called free radicals, which cascade through a chain of chemical recombinations and damage lung cells in the process. (It is free radicals that also cause tissue damage associated with radiation and cigarette smoking.)

Whether this pulmonary barrage from ozone causes long-term lung damage is a question that remains unresolved.

O’Neil noted that EPA studies have detected cell damage and chemical indications of acute inflammation when they sample lung fluids of people who have exercised in an ozone-polluted environment.

“Presumably the body can be insulted with something like ozone and it has an inflammatory response and it repairs itself,” he said. “But if this occurs on a daily basis for 20 years, is there a possibility that there might be 10% or 15% of the population that develop excessive loss of lung function? It’s a distinct possibility. That’s what happens in smoking--about 15% of the population has big-league loss of pulmonary function that occurs 10 to 20 years after they start smoking.”

Kleinman noted that after particularly heavy ozone exposure in animals, minute amounts of the fibrous protein collagen are left deep in the lung. Over many years of ozone exposure, this collagen could build into scars and diminish lung capacity, he suggested.

Long-Term Project Proposed

EPA is considering launching a long-term project to try to settle the issue by monitoring lung health in polluted areas, O’Neil said, but it wouldn’t begin to show results for several years.

In the meantime, the experts advise Southern Californians to do heavy exercise such as running when ozone is at its lowest levels, in the early morning or the evening--and definitely not at lunchtime. Although ozone levels generally are highest from noon to 4 p.m., during summertime high levels occur earlier in communities farthest from the ocean.

Summer ozone levels that preclude outdoor exercising occur by 9 a.m. in the Glendora, Fontana, San Bernardino and Riverside areas, by 10 a.m. in La Habra and Reseda, by 11 a.m. in downtown Los Angeles. And in Palm Springs peak levels occur very late in the day, at around 6 p.m.

This phenomenon occurs because in summer the prevailing ocean winds often blow auto emissions northeast toward the San Gabriel Valley and east to the Riverside-San Bernardino area, but the night winds are too weak to blow the resulting ozone back toward the ocean. This pollution cloud sloshes back and forth unequally within the basin, building up more and more ozone to blanket inland communities if the weather pattern continues.

Other pollutants in the region’s air have different dispersion patterns and result in different health effects. They include:

PARTICULATES Small particles of soil, biological materials and compounds containing carbon, nitrogen and sulfur are the main culprits in the smoggy haze that limits visibility in the Los Angeles basin. Like ozone, they reach their highest levels downwind of the area where their precursors were emitted. In general, the highest levels occur on spring and summer days, but in Long Beach they peak in mid-winter.

Particulates can provoke or worsen asthma and chronic bronchitis and particularly affect the elderly and children, studies have shown. One study in the southeastern United States found that children breathing high levels of particulate sulfur dioxide had more croup, bronchitis, pneumonia and hospitalizations than did children living in less polluted areas. Sulfur dioxide is not a problem in the L.A. basin.

The recent air quality district study estimates that the smallest of these particulates, inhaled deeply into the lungs, causes 1,617 deaths in the L.A. basin every year.

This conclusion is based, however, on extrapolation from serious pollution episodes in Europe and the eastern United States, where the particulate mix was different. Coal and oil burning add more sulfur compounds to the air there than exist in the L.A. basin.

CARBON MONOXIDE Carbon monoxide is a colorless, odorless gas emitted by cars and whose effects are among the best known of pollutants. It blocks the chemical receptors that carry oxygen in the blood, cutting down on the body’s supply of oxygen. In suicides or home heater malfunctions, it causes death. In urban environmental doses, it can cause headaches, dizziness and shortness of breath.

Recent research also has shown that low concentrations of carbon monoxide in the blood can bring on the chest pains of angina, a precursor to heart attacks. Doctors warn people with ischemia, oxygen deprivation in the heart muscle, to avoid heavy exercise in traffic-congested areas.

Unfortunately for L.A.-area exercisers, they sometimes may face a choice between carbon monoxide and ozone. Although coastal ozone levels are lower than inland areas, carbon monoxide is more likely to exceed state standards nearer the coast than inland. Furthermore, daily peak levels of this gas occur in the early morning and early evening, just when the ozone concentration is at its lowest. Carbon monoxide also is higher in fall and winter, while ozone is higher in summer.

NITROGEN COMPOUNDS Autos emit a colorless gas called nitric oxide, which immediately reacts with oxygen in the air to become nitrogen dioxide. This brownish gas smells a little like bleach and has its highest concentrations around busy highways. Its highest levels come from October through February.

Experiments have found nitrogen dioxide appears to cause twitchiness in the lungs, a condition that would be a slight problem only for people who already have asthma. One study found that taking Vitamin C blocked this effect.

There are also hints in animal studies that, like ozone, nitrogen dioxide may quicken the growth of existing cancers of the respiratory system.

In sunlight, nitrogen oxide gases react to form nitrate compounds such as ammonium nitrate and sodium nitrate, which remain suspended as particles in the air and reduce visibility. Nitric acid, which can irritate the eyes, also is formed.

SULFUR COMPOUNDS The industrial pollutant sulfur dioxide is one of the few pollutants not abundant in the Los Angeles Basin’s air. At its highest level, it is still 50% or more below the state standard. The heaviest concentrations occur near Long Beach. It can cause coughing and nose, throat and eye irritation. Sulfur dioxide also leads to formation of irritating sulfuric acid during periods of high humidity.

Where Pollution Goes Ozone Ozone is worst in eastern areas of the district. Highest levels, 175 days a year, occur nearGlendora. Carbon Monoxide Inland areas are only slightly affected by excessive carbon monoxide. Most is coastal. Particulates Responsible for decreased visibity, particles smaller than 10 microns lodge deeply in lungs. SOURCE: South Coast Air Quality Managment District, based on 1985 figures.