Scientists are just starting to understand the tiny particles in air pollution and how they damage the body.

WHEN ED AVOL races 5Ks around Southern California, the avid runner sees more than the competitors he’s passing. He thinks about the area’s roadways, the heat, the humidity and the air he’s breathing—and what’s in it.

More than most athletes, Avol understands the ins and outs of air quality. He knows how far Los Angeles has come in cleaning up the air, and how much still needs to be done. He’s seen it first hand not only as a runner and an LA resident for 50 years, but also as a USC scientist who studies air quality and its effects on people and the environment.

Avol and his fellow researchers in the Department of Preventive Medicine at Keck School of Medicine of USC have studied the impact of air pollution on the health of kids in Southern California since the early 1990s. Supported by some $30 million in research grants, their decades of work have shed light on smog as an urgent, chronic health concern. It has given objective scientific evidence to clean-air advocates working to tighten emissions standards and bring clear skies back to Southern California.

The researchers do more than publish their science: They use their expertise to improve and protect public health.

From Idea to Answers

Years ago, Southern Californians suffered through hundreds of days a year of eyestinging, chest-burning smog. Researchers then mostly looked at air pollution’s acute health effects—what happens to lungs within minutes or hours of breathing smoggy air, Avol says.

But USC scientists suspected pollution’s deeper impact lay in its effects over the long term, especially in kids. What would years of exposure to air pollution do to children as they grew up? How would breathing this air affect the rest of their lives?

To answer these questions, the late John Peters, director of the environmental and occupational health division at the Keck School of Medicine, proposed the Children’s Health Study.

In 1993, Peters assembled a group of researchers and started the project with state funding. They enrolled 3,600 fourth-graders from 12 Southern California communities ranging from San Diego to San Luis Obispo counties. Some children lived in areas with more air pollution, like Long Beach and Riverside, while others grew up in lower-pollution areas like Lompoc and Santa Maria. Each year, the children’s families answered health questions—whether their child had a respiratory infection or developed asthma, for example—and each child took an annual breathing test in school.

The researchers also continuously monitored air quality in the communities, measuring key pollutants such as ozone, particle matter and nitrogen dioxide.

The study focused on children because their bodies are still in development and they’re typically more active and spend more time outdoors than adults. Lung deficits early in life can lead to a cascade of health effects later, including heart and lung problems and even early death from heart or lung disease.

It took only a few years to start to see some patterns in the data that caused concern, says W. James Gauderman, a biostatistics professor in the Department of Preventive Medicine and 19-year veteran researcher on the study.

In 2004, the group found that children from communities with poor air quality had less-developed lungs during their teen years than kids who grew up in cleaner areas. In 2007, they showed that lung function development among children living close to roads was especially stunted. The results got worldwide attention.

There were other unexpected findings along the way. “We were surprised to find in our unique scientific study that ozone wasn’t the biggest problem,” says Frank Gilliland, Hastings Professor of Preventive Medicine and director of the Southern California Environmental Health Sciences Center, which is funded by the National Institute of Environmental Health Sciences. “It was this mixture of nitrogen dioxide and fine particulate matter that had long-term effects on children, especially on their lung development and with asthma exacerbations.”

Researchers are still learning how exactly air pollution causes an assault on the lungs. “We suspect that there is chronic inflammation in the lung tissue due to breathing polluted air,” Gauderman says.

Regardless of how air pollution wreaks its damage, the researchers see reason for optimism. Their most recent findings, published in the New England Journal of Medicine earlier this year, showed that improvements in air quality have finally paid off in better respiratory health for children.

Since the mid-1990s, levels of particulate air pollution in Southern California have dropped by 50 percent, Gauderman says, because of the efforts of the city, state and ports to crack down on dirty cars, trucks and ships. “So this provided an ideal backdrop to see if better air led to bigger, healthier lungs,” he says.

Indeed it did. When the researchers looked at data from 2,000 children in five cities, they saw that as air pollutant levels dropped, fewer kids had low lung function. The percentage of children in the study with abnormally low lung function at age 15 dropped from nearly 8 percent (for a group of children followed from 1994 to 1998) to less than 4 percent (for children followed between 2007 and 2011). They saw improvements across all ethnic groups, even among kids without asthma or other respiratory conditions. “This suggests that all children benefit from breathing cleaner air,” Gauderman says.

Outreach Matters

The USC researchers have gone beyond using science to illuminate a health problem: They’re about practical solutions and interventions. Today, they continue to educate Southern Californians about air quality and advocate health.

Andrea Hricko has seen the scientists’ work alter environmental policy in the Los Angeles region for the better. Hricko directs community outreach and engagement programs for the USC Children’s Environmental Health Center and the Southern California Environmental Health Sciences Center.

Fourteen years ago, the centers’ outreach program organized a community meeting to listen to hundreds of residents’ concerns about air quality in their neighborhoods. “For the first time, we started hearing a lot about ship emissions from the ports of Los Angeles and Long Beach,” says Hricko, professor of clinical preventive medicine. “Residents near the ports and alongside the 710 Freeway complained that trucks were suffocating their communities.”

That meeting spurred the scientists and outreach staff to focus new research and education efforts on reducing pollution from transporting freight—mostly containers packed with consumer goods from Asia that arrive on ships and end up on trains and trucks.

Since then, USC has regularly submitted studies on air pollution’s health effects to the harbor commissions of both ports to ensure that officials factor in public health and air pollution when considering expansion. The centers’ outreach staff translate new scientific research to community members who, in turn, fight to cut air pollution. A combination of research findings and work by well-informed community advocates and environmental groups rompted the ports to enact new programs: Trucks must have cleaner-burning engines, and ships now plug into electrical power when in the harbor, improving air quality for millions of people.

A half-dozen community conferences followed the 2001 meeting, including scientists like the Keck School of Medicine’s Avol, Gauderman, Gilliland and Rob McConnell, deputy director of the Children’s Environmental Health Center. In one recent meeting, 710 Freeway-area residents shared concerns about freeway expansion projects. The USC team presented residents’ public comments to Caltrans, the state transportation agency. “We try to have the transportation agencies understand that expanding freeways to handle more cars and trucks is not a 21st-century solution to reducing congestion and air pollution,” Hricko says.

Gilliland notes that the region’s air quality still fails to meet Environmental Protection Agency standards, and health can still suffer. But there’s reason for optimism.

“I think this is a ‘good news’ story,” Gilliland says. “We still have a long way to go for clean air in Southern California, but we have environmental health problems we can fix through science-based interventions, and it illustrates that taking a scientific approach works.”

Southern California can be an example for the rest of the world, he adds.

“What we’ve done is show that the interventions are worth it in the long run,” Gilliland says, “and USC has the opportunity to continue to be a world leader in developing the science to support continued improvement in the air we all breathe.”

HealthScience/TechnologyCommunity HealthEnvironmentLos AngelesPublic HealthResearch