Asthma. The word itself sounds phlegmy and tight. It wheezes. From presidents (Teddy Roosevelt) to Olympic athletes (Jackie Joyner-Kersee), people have learned to live with it, even control its sudden, chest-gripping attacks.

At its worst, Bradey McDaniel’s asthma makes her feel like she’s breathing through a straw. “I can’t sleep,” she says. “My chest feels bruised and my ribs are sore.” The 1998 UNC-CH graduate says this with a hand at her throat, seated on a hospital bed. Dressed in tennis shoes, a t-shirt, and shorts, she doesn’t look like a fourth-floor patient at UNC Hospitals. She even brings her own medicine, two inhalers. One includes a steroid that helps relax clenched bronchial tubes. The other she takes before exercising, something she likes to do even when fall pollen counts and air pollution levels peak.

In three days of tests, with overnight hospital stays just to be safe, McDaniel helps researchers monitor the effects of one type of air pollution, endotoxin. She volunteers for the Center for Environmental Medicine and Lung Biology. So far, the best that medical researchers can do for asthma sufferers is to make the coughing and wheezing bearable. They can’t make it go away because there’s no cure for asthma. But identifying just what triggers it could help reduce the frequency of asthma attacks for the 10 million people in the U.S. with the disease, of whom three million are under 18 years of age.

The plexiglass chamber where McDaniel sits for four hours at a time holds little more than a chair and a sign she can hold up that says, “Break Time.” A shiny space-age looking duct pumps in air that contains a calibrated amount of endotoxin—tiny bits of dead salmonella or E. coli bacteria that can cause fever and shock in extreme cases. Endotoxin has been linked to indoor air pollution. But it’s also found outside in everyday air, too. McDaniel says the endotoxin that she breathes amounts to what a person would breathe normally.

It isn’t that bad,” she says. “They let you out to go to the bathroom.”

They” are researchers from Carolina working on the fifth floor of the Environmental Protection Agency/UNC Research Facility. David Peden, associate professor of pediatrics, says the experiment is designed to see whether endotoxin kickstarts asthma. Every 20 minutes, McDaniel blows into a peak-flow meter, a handheld tube that records her lung capacity. After the ninth time, she drops 20 percent below her normal capacity. When her lungs drop this low, she usually turns to an inhaler for relief.

Peden says air pollution doesn’t cause asthma. But it can make life worse for people who already suffer from it. “My suspicion is that the effects of endotoxin, and a lot of particulate matter, are probably things not usually experienced by the general population.”

So what does air pollution do to most people’s lungs? In collaboration with the EPA’s Human Studies Division, Carolina researchers have been chipping away at that question for nearly 20 years. Studies in the field have shown that high air pollution counts coincide with increased cardio-respiratory death. “You’ve seen the headlines,” says Bob Devlin, EPA’s chief of clinical research at the division. “Fine particles kill thousands of people each year.”

Much of the collaborative research will support new air pollution regulations. Research at the facility spurred national ozone standards last year. In order to help regulators set standard levels, scientists have to pinpoint what level of exposure people are likely to encounter outside and on the job. “Our research may have a multibillion dollar impact on industries,” says Devlin. “A lot of lawyers are looking at our work.

But the big problem with epidemiological studies right now is that people are saying, `Yeah, I see what you said. But I can’t think of any mechanism in the world that would explain how someone can die 24 hours after they breathed in just a small number of particles,’” Devlin says.

The EPA building’s red brick façade, girdled by concrete columns, seems solid enough. But inside it’s mostly air. Seven giant chambers allow researchers to run a series of tests on people simply to see how they breathe. Breathing clean air or polluted air while walking a treadmill, riding a stationary bicycle, relaxing with a book, or in the dark, completely quiet.

On top of the building sits a device that Dr. Suess could have dreamed up, an ambient air concentrator. It sucks in Chapel Hill’s air pollution and packs it 10 times as dense as what blows outside the windows. “The exposure facility is the best of its kind in the world,” Devlin says.

Step inside one of Bob Devlin’s chambers and you quickly get the picture. The entire ceiling is one huge duct. Below your feet, the floor looks like a giant, flat colander punctured with dime-size holes. Underneath that lies an equally giant exhaust duct.

This way we can make sure that the air quality is the same throughout the entire chamber,” Devlin says. It also means researchers can test a group of people simultaneously, under the same conditions. “When we expose people in the chambers, we ask the question, `what’s happening, what does the particle do?’” he says.

When particles get inside your lungs, a lining of epithelial cells tries to protect airways. In the last few years, scientists have discovered that these cells also act as triggers. They start a cascade of events that results in lung injury. The cells release compounds that start inflammation. Bronchial passages end up tied into knots.

But which one is the guilty particle? Peden, the asthma and allergy doctor, says one problem in studying fine particles is that they consist of a multitude of chemicals, unlike ozone for instance, which is a discrete gas. The ongoing debate centers on whether the offending particles are biological, like endotoxins, or metals like iron, zinc, and copper released by burning fuel oil or coal.

One thing they do have in common is that they’re solid, microscopic, and respirable,” he says. “The people at risk are people that for whatever reason have an increased sensitivity to air pollution. That’s led to the notion of studying susceptible populations. There are many ways you can identify such a population. One is by having a certain disease, like asthma.”

Back at the hospital, Bradey McDaniel gets ready to check out and go home. She says that she’s grateful both for the paycheck she earned and to be part of the research. Diagnosed with asthma in the ninth grade, McDaniel just enjoyed her first spring without an asthma attack.

But I wish I had known about my asthma even sooner,” she says. “Now that I know what I’m allergic to, I can control it.”

Christopher Hammond was a student who formerly contributed to Endeavors.