UC Davis expertise reaches out to communities near and far to help ensure a healthy environment

Photo of Dr. Cahill Thomas Cahill, professor emeritus of physics and atmospheric science at UC Davis, gained national attention for his studies of the air around the World Trade Center after Sept. 11, 2001.

Writer Eric Gillin was one of a cavalcade of people who were enveloped and choked by a cloud of dust while fleeing the World Trade Center on Sept. 11, 2001. When Gillin reached home that day, he stuffed the backpack and clothes he wore into a trash bag and stashed it in his closet — for five years.

He rediscovered the artifact and realized it might solve the mystery of what materials were in that initial blast. Nervous about his long-term health, Gillin looked for an expert who could analyze the rare and valuable dust.

New look at old dust

That led him to Tom Cahill, professor emeritus of physics and atmospheric science at UC Davis. Cahill had a special method for sampling and analyzing airborne particulates, and he had sent an air sampler to a site close to Ground Zero to study what spewed out of the burning wreckage several days after the towers fell. That plume was highly toxic, he reported.

Cahill was delighted to get the backpack from Gillin, who told the story in the March issue of Esquire magazine. And the findings?

"The good news is that the dust was mostly harmless gypsum, concrete and aggregate," Cahill says. "The initial building collapse produced an enormous quantity of airborne material, but the toxicity was low." Gillin — and all the others who were exposed — can breathe a sigh of relief.

Finding answers

By jumping at rare opportunities and exploiting their expertise, researchers at UC Davis are often the first to answer important questions about the impact of the environment on the health of communities it serves. Sometimes their studies reassure people that there's little to worry about. But just as often, the data they gather enables communities to put in place new policies that better protect the public's health.

Closer to home, take a look at El Dorado Hills in California's Sierra foothills. Researchers at UC Davis' Department of Public Health Sciences have contributed to sweeping changes in this booming bedroom community. And these actions should reduce residents' risk of a rare form of lung cancer called mesothelioma.

Driving public policy

In 2005, the researchers reported results from the first comprehensive study to investigate whether living near naturally occurring asbestos deposits raised the risk of mesothelioma. "We did the study because I'm a firm believer that science should be the basis of good public policy, and there was a lack of data on this question," explains Marc Schenker, lead author and professor of public health sciences.

Science should be the basis for good public policy, says public health expert and UC Davis professor Marc Schenker.

Photo of Marc Schenker"The way to address this issue is not to wait 30 years and count bodies; the way to address it is to deal with it now."
— Marc Schenker, professor of Public Health Sciences

The multidisciplinary team saw an opportunity to get answers by using California's statewide comprehensive cancer registry to obtain addresses of people with mesothelioma; they mapped those data and compared them with a geological map of the state's ultramafic rock formations — which contain asbestos.

"There was something going on," says Laurel Beckett, biostatistics professor who worked closely with graduate student Xuelei Pan on the analysis. "Mesothelioma cases were showing up more concentrated near the asbestos deposits," even when other confounding factors were considered. The risk of mesothelioma fell by 6 percent for every 10 kilometers farther away from the outcrop a person lived.

Educating residents

As a community with significant amounts of naturally occurring asbestos, El Dorado Hills took notice.

"When this study came out, it made me nervous — just as a mom," says Laura Gill, who's the chief administrative officer for El Dorado County and a mother of three.

The community responded by launching a campaign called BEACON to educate developers, local agencies, schools and citizens about how to reduce exposure by keeping the dust down. A hotline was established to report developers and builders who weren't following guidelines, such as watering construction sites and cleaning up streets. Some bike trails were paved, and the county health department now advises residents to take off their shoes when entering the home, and to keep windows closed on windy days.

Says Gill, "For me, it's about making sure you know what you need to do — like wearing a helmet when riding a horse."

National implications

Because at least 40 other states have ultramafic rock deposits, the research might even lead to national changes in health policy. Schenker is currently working with the American Thoracic Society to bring wider attention to the risks of exposure to naturally occurring asbestos, so that other communities can take action to minimize dust, if appropriate. Says Schenker: "The way to address this issue is not to wait 30 years and count bodies; the way to address it is to deal with it now."

Cahill has also engaged in local research that could have national implications. For the past five years, he's been monitoring and analyzing the particulates in air along a busy road in Sacramento called Watt Avenue.

"We wanted to give people an accurate characterization of what they're breathing near the secondary roads, as opposed to freeways," says Cahill. "To our surprise, in some places the pollution was as bad as from Interstate 5." Ordinary cars — not just diesel trucks — spew ultra-fine particles that can get deep into the lungs, he found. These include the potent carcinogen benzo(a)pyrene, toxic metals, and lung irritants that can exacerbate asthma.

School takes action

The study results spurred Arden Middle School, which lies downwind of Watt Avenue, to take action to protect the health of its students. The school planted a row of trees to block traffic fumes, and installed new air filters in classrooms to remove particulates.

Researchers at the UC Davis Department of Public Health Sciences found an increased risk of a rare form of lung cancer caused by naturally occurring asbestos in the booming bedroom community of El Dorado Hills. Sweeping changes since the discovery should reduce residents' risk.

"One gross emitter equals 300 clean cars," he notes. Senate bill AB 1870 was signed into law last year, and beginning Jan. 1, 2008, cars emitting tailpipe smoke will no longer be able to pass the smog test.

Breathe California is using Cahill's data to argue that the California Air Resources Board should consider these ultra-fine pollutants toxic and set health standards for them, just as they do for diesel soot, according to Betty Turner, a health policy consultant for the organization. "And we're putting that data in front of the federal EPA, hoping eventually for a national standard," she says. "The work that Tom does is way ahead of what anyone else is doing — truly cutting edge," she notes.

Training new professionals

Having worked with Cahill for more than a decade, Turner quips that "he sometimes leaves others in the dust," even though he's been officially retired since 1994. Who will follow his lead? In the future, who will give investigative reporters, growing communities, medical organizations, and state activists research data and advice on environmental health issues?

Schenker and Beckett say they're eager to recruit and prepare the next generation of public health professionals. "Our goal is to train not only people who do research to answer important questions, but also people who work closely with the public — those who can take what we learn and make better health practices possible," says Beckett. "There's a huge need for that."

Schenker adds, "The effort to create a new School of Public Health at UC Davis is precisely to increase the training of public health professionals to achieve these goals.

Indeed, it takes good health information from well-trained professionals to give people — a mother in El Dorado Hills, a school child in Sacramento, a writer in New York City — a reason to breathe easier.