Into the Wilds of Oakland, Calif.

When Juan Hernandez moved to West Oakland from Bakersfield, Calif., one year ago, his asthma flared up. He used his inhaler more and more often and, eventually, had to give up his favorite sport: running. "I was huffing and puffing, but I thought, It's my own personal problem," says Hernandez, 17. Then, while working on a school assignment, he discovered otherwise. His environmental-law teacher sent Hernandez and his classmates on a "toxic tour" of their neighborhood: they walked around and wrote down what they saw, what they smelled and how they felt. This particular section of West Oakland, which lies in the shadow of a tangled web of four freeways and the Port of Oakland, has the second highest rate of asthma in the city. As Hernandez strode a few blocks from school, he passed a scrap-metal recycling plant and aluminum smelter that "smelled nasty," he says. It was an "aha" moment: "I said to myself, 'I'm living in this place that has some of the worst pollution in all of Oakland, and I gotta do something about it'."

He did. With support from the state and two environmental nonprofits, the Rose Foundation for Communities and the Environment and Global Community Monitor, Hernandez and his classmates tested the air outside their school and found elevated levels of heavy metals, including lead and nickel. In May, the students held a news conference outside their school to announce their findings. The event drew news coverage and grabbed the attention of neighbors, city-council members, and even the scrap plant, which has since cleaned up metal debris from the area.

Hernandez's program is one of a growing number that are helping turn young people from underprivileged neighborhoods into pollution sleuths and community activists. Robert Bullard, director of the Environmental Justice Resource Center at Clark Atlanta University, estimates that there are more than 1,500 such groups, up from only a handful 20 years ago. Some are initiated by young people, some by teachers or area residents and others by civic or environmental nonprofits. They're fueled by growing awareness of the environment's impact on health as well as by the expansion of the green movement beyond traditional issues like conservation. "Young people are reframing what it means to be a modern environmentalist," says Sharon Smith, program director of the New Leaders Initiative at San Francisco's Earth Island Institute. "Urban areas are just as relevant to the environmental movement, and a lot of young people have been on the forefront of that change, looking at issues of power and privilege."

Many of the groups target air pollution, which disproportionately affects low-income neighborhoods. A study that Bullard coauthored last year found that neighborhoods that host hazardous-waste facilities have a far higher minority population and poverty rate than neighborhoods that don't. A 2005 analysis by the Associated Press of EPA figures found that black Americans are 79 percent more likely than whites to live in neighborhoods where industrial pollution is suspected of posing the greatest health danger. Many of these same communities also have higher rates of asthma, for which pollution is a trigger. Dr. Jay Portnoy, president of the American College of Allergy, Asthma and Immunology, says automobile exhaust and petrochemicals interact with sunlight to form ozone, which is among the worst of the lung irritants that trigger asthma, though any kind of particulate matter will affect asthma sufferers more severely.

As interest in youth activism and environmental justice has grown, so has funding for the programs. The Ford Foundation, the Earth Island Institute and the Surdna Foundation are among the groups that have stepped up support for these efforts. "It reflects an overall shift in interest toward global warming and environmental causes," says Jee Kim, a program officer at Surdna. The Earth Island Institute launched its Brower Youth Awards, for leaders ages 13 to 22, in 2000 and has been awarding more grants to young people involved in environmental justice.

One of last year's recipients was 18-year-old Erica Fernandez from Oxnard, Calif. When she was 12, she attended a local beach clean-up day where someone told her about a proposed liquefied-natural-gas facility to be built off the coast of her community. Her father, a retired fieldworker, has such bad asthma that he keeps an oxygen tank at home to help him breathe. "That's what motivated me," she says. Fernandez organized 3,000 people, including 300 students, to protest against the facility at a rally. In April 2007, she passionately testified in front of the California State Lands Commission and the California Coastal Commission, which both then voted against the project.