Pollution produces tangible negative effects on children’s health and federal regulations are not currently strict enough to protect them, said a panel of experts at a Congressional briefing Friday.

Hosted by the Environmental and Energy Study Institute, the event focused on the impact of various pollutants including ozone, particulate matter and mercury on respiratory health and cognitive development.

Eighteen-year-olds who live in polluted areas are four-to-five times more likely to have abnormal lung function, according to a report presented by W. James Gauderman, associate professor at the University of Southern California’s Department of Preventive Medicine. Based on a series of longitudinal studies of children in Southern California, the report also suggests that high levels of ozone, which at low altitudes is a pollutant, increases school absences due to acute respiratory disease and elevate rates of asthma onset and attacks.

These findings, Gauderman said, occurred at pollution levels that are below Environmental Protection Agency (EPA) standards, which are currently set to prevent acute but not chronic health problems.

The study also found that children who live close to freeways and high-traffic areas had greater exposure to nitrogen dioxide and greater prevalence of asthma.

“Living near traffic is an environmental justice issue,” said Janice Kim, public health medical officer with the Office of Environmental Health Hazard Assessment of the California EPA, because children of low-income and of color are more than three times more likely to live near busy roads.

Although levels of another pollutant, mercury, appear to have declined over the past decade, the element is “very persistent,” said Lynn Goldman, professor at the Johns Hopkins University Bloomberg School of Public Health’s Department of Environmental Sciences. “Once it’s in the environment, we don’t really have ways of pulling it out of the environment, of cleaning it up.”

When mercury contaminates water and soil, microorganisms turn it into methyl mercury, which enters the food chain. Contaminated fish are the most common source of methyl mercury exposure in humans.

Fetal exposures to mercury have been linked to IQ deficits. Goldman cited one study suggesting that over 300,000 American babies per year are born with unsafe blood mercury levels.

Another study suggested that these lost IQ points as a result of mercury emitted from U.S. power plants cost the U.S. economy $1.3 billion a year in lost productivity.

Both studies originally appeared in the peer-reviewed journal Environmental Health Perspectives.

Because mercury in the air can travel all over the world, said Goldman, “we need to move forward at all levels,” global, national, and local.

“We can actually affect the amount of mercury going into the environment by taking action,” she said. Goldman said she was disappointed by a March EPA decision to drop more stringent “Maximum Achievable Control Technology” standards in favor of “cap and trade” regulation.

Further, she pointed out that the EPA and Food and Drug Administration have different standards of safe levels of mercury exposure. The EPA “Reference Dose” reflects the National Research Council’s recommendations, while the “Tolerable Daily Intake” of the FDA is considerably higher.