THE BUSH PLAN FOR CLEAN AIR : Scientists Voice Concerns Over Pollution’s Effects : Health Risk Data Prompts Action

The average person who sits absolutely still and does nothing will nevertheless inhale about 2,000 gallons of air every day.

In a polluted environment, “that’s a lot of air going in and out, and with toxic things you can’t filter very well,” said Dr. Samuel Spagnolo, director of the division of pulmonary diseases and allergy at George Washington University Medical Center. “We don’t know what 30 years of this is going to mean.”

Approximately 62% of all Americans--150 million people--live in places where the air contains pollutants that exceed one or more of the health-based federal standards for air quality, according to the American Lung Assn.

“No reputable member of the scientific community questions the potential risk to human health of air pollution,” Bailus Walker Jr., a State University of New York environmental health professor, said in recent congressional testimony. “For all pollutants, there is a limit beyond which health and life are threatened.”

These concerns underscore why, at a time when there is still resistance to increased government regulation and expensive new federal initiatives, the Bush Administration and Congress are preparing to do battle with one of the costliest and most politically complicated problems of all--air pollution.

After years of procrastination, government leaders in both parties are concluding that for the sake of public safety the challenge must be addressed sooner rather than later.

“Every American expects and deserves to breathe clean air,” declared President Bush in announcing his long-awaited plan Monday to improve air quality in the nation’s most polluted cities.

Two Types of Pollution

The chief culprits in tainted air include toxic emissions, known to cause cancer and other health problems, but which usually affect only those who live near polluting industrial sites; and smog, to which a much larger population is exposed for long periods of time.

Smog is composed of carbon monoxide, sulfur dioxide and, foremost, ozone, a highly reactive gas formed when the sun heats airborne mixtures of nitrogen oxides and other organic compounds.

The smog ingredients are all respiratory irritants that cause inflammation of the body’s airways, experts say. One of the nitrogen oxides, nitrogen dioxide, also interferes with the functioning of the body’s immune system and can lower resistance to influenza and other lung diseases. Carbon monoxide prevents oxygen from binding to hemoglobin in the red blood cells, thus reducing the body’s oxygen supply.

Researchers who have been studying the health impact of breathing dirty air are virtually in agreement on its short-term effects--they can be acute and immediate, although reversible. They include coughing, chest tightness, wheezing, watery eyes, sneezing, shortness of breath, and even severe chest pain.

For most people, these are annoyances that will disappear once the air quality improves.

But the scientific community is far less certain of air pollution’s long-term effect. They suspect, however, that it is serious and will not prove to be fleeting. Studies using animals have shown lung scarring, permanent lung impairment and the development of chronic respiratory diseases, such as emphysema, and even heart disease.

“Even though you cannot extrapolate to humans without some degree of uncertainty, there is legitimate reason for concern,” said Dr. Robert Frank, professor of environmental health sciences at the Johns Hopkins School of Public Health. “The lungs of the animals have many structural similarities to human lungs, and if our cells see that ozone they’re probably going to react the same way.”

Rate of Lung Aging

Frank, a former member of EPA’s clean air sciences advisory committee, added: “I’m convinced that ozone is probably accelerating the rate at which the lungs age in communities where people are exposed repeatedly to it.”

There is no clear evidence, however, that ozone contributes to the development of lung cancer.

“Some strains of mice that are susceptible to developing tumors were exposed to ozone and they developed more tumors when exposed to ozone than when exposed just to filtered air,” said Dr. Henry Gong, associate professor of medicine at UCLA’s pulmonary division. “Ozone exposure does accelerate the numbers of cancer in those mice. But I don’t know what that means for humans.”

At UCLA, Gong and his colleagues are seeking answers about both the short-term and long-term effects of ozone on about 150 people who live in Glendora, an area that Gong describes as “historically notorious for its recurrent air pollution episodes.”

To study the acute, short-term effects, about 50 members of the Glendora group visit UCLA Medical Center once a week to sit in an 8-foot by 8-foot by 8-foot plexiglass chamber for two hours, where they alternately exercise for 15 minutes and then rest. In one session, they are given air containing 0.4 parts per million ozone, equal to a second-stage smog alert in Los Angeles. In the control session the following week, they get clean, filtered air to breathe.

Typically, after the ozone session, they demonstrate lung impairment, which is reversible, Gong said.

Gong and his colleagues also intend to study these people over time, to determine whether their lungs will develop a tolerance to ozone, or whether they will show permanent damage.