Invisible Killers: Air Pollution and Asthma

By Owen C. Franklin

"Today, the air is dirtier than it was twenty years ago. That must be contributing to the asthma epidemic."

Despite what his friends might say, eight-year old Vernell Bourne does not carry a purse. The small pack he straps to his side is a miniature air monitor.

"It's for a study that they're doing about what kind of air we're breathing into our lungs," said Vernell.

Vernell and nine of his classmates at the Kunsberg School in Denver (CO) are agents in a groundbreaking project. They will each carry a walkman-sized air monitor for two weeks. At home, school and play, the monitors will gauge what is floating around in the air they take into their lungs.

"It seemed strange at first," said Vernell. "But then I realized it was for asthma."

Vernell, like some 17 million Americans, has asthma. And the numbers are growing. In the past five years, reports of asthma increased by nearly 20 percent.

While the problem is clear, the cause is less easy to target. More and more, physicians and health officials across the country are pointing their fingers to the thick sooty clouds that linger over our cities and homes.

It seems rather simple: dirty air is hard to breathe. Today, the air is dirtier than it was twenty years ago. That must be contributing to the asthma epidemic.

But common sense assumptions don't carry much weight in scientific circles.

"It seems obvious," said Dr. H. James Wedner, Chief of Clinical Asthma at the Washington University School of Medicine. "But it's been fairly difficult to show that air pollution is causing the increase of asthma."

One problem, according to Dr. Wedner, is that air pollution is just one of many possible culprits. Everything from increased exposure to indoor allergens to our dependence upon antibiotics could be giving asthma a leg up.

The other problem is that those thick sooty clouds are hard to calibrate.

Countless bits of gasses and solids congeal to form air pollution. These tiny flecks, called particulate matter, come from a wide spectrum of sources such as ozone, smokestacks and car exhaust.

Here's the question: if air pollution is affecting asthma, which and how much particulate matter is dangerous?

Hopefully, Vernell Bourne and his miniature air monitor will help provide an answer.

Vernell's monitor can indicate how much particulate matter he encounters on a daily basis. By checking these levels against his patterns of asthma attacks, physicians leading the study may be able to determine how much particulate matter triggers asthma.

"We don't really know how air pollution works," said Nathan Rabinovitch, M.D., assistant professor of pediatrics at National Jewish Medical and Research Center in Denver (CO). "With these monitors, we hope to see if there is a correlation between air pollution spikes and episodes of asthma."

Dr. Rabinovitch is directing this study through a grant from the Environmental Protection Agency (EPA). The two-year project includes several objectives, such as determining which types of particulates (i.e. ozone or smoke) pose the greatest problems and how long it takes for air pollution to trigger an asthma attack. All this research could help corroborate, or redefine, current clean-air safety standards.

"Right now, the standards are kind of arbitrary," said Dr. Rabinovitch. "They are set up, and if the levels get too high, you get a red flag. But it seems that there is no real 'safe area' and that cities that are within air safety standards may still have problems."

These days, our safety standards are drawing a lot of hot air — and it's all coming down to bits and pieces smaller than the width of a human hair.

Air quality standards depend, in part, on the size of the particulate matter in the air. Under current standards, air quality becomes unsafe when it contains particulates larger than 10 micrometers (10,000 micrometers equals one centimeter). But the EPA is working to control these standards with stricter guidelines.

In 1997, the EPA tightened the safety standards to 2.5 micrometers. But several industries that produce particulates in their production, such as trucking and lumber, objected this move. The industries sued the EPA, claiming the new standards would be both too costly to enforce and ineffective in reducing air pollution. The 10-micrometer standard was re-instated.

The EPA continues to research air pollution to strengthen its case for tighter standards. This year, the agency funded a list of new projects and institutions to zoom in on the microscopic mystery.

The projects span the country and research the different types of air pollution that are spawned in different areas.

In the Northeast, there's New York University's new Center for Particulate Matter Health Research. In the middle of the country, there's Dr. Rabinovtich and Vernell Bourne. In the Northwest, there's Jane Koenig, Ph.D., director of the EPA's Northwest Center for Particulate Matter and Health Research.

Armed with air monitors strategically placed throughout the Seattle area, Koenig tries to decipher the amorphous force of air pollution.

"Air pollution is very heterogeneous," said Dr. Koenig. "It varies from season to season, it can vary from hour to hour. If you're downtown, you could be breathing different air than you'd breathe 10 blocks in any direction."

This makes researching air pollution's affects on asthma both complex and costly.

"Asthma attacks everyday," said Dr. Koenig. "If you don't have monitors running constantly, it can be very hard to understand any relationships that might exist."

While the complexity of air pollution will pose problems in future research, health experts have good reason to continue their studies. The harmful effects of ozone on asthma have already been clarified, and other studies are addressing how auto exhaust can trigger an attack.

Hopefully, new projects will clear the haze. With everyone from health experts to eight-year old Vernell Bourne pitching in, we may soon get the dirt on those thick sooty clouds.

"They want to learn about asthma and how they can treat it," said Vernell. "And I'm helping them help out my asthma."

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