An air quality monitor near the Georgia Tech campus in downtown Atlanta has become the latest political football in an intense debate about the dangers of power plant pollution.
Executives at Southern Co. say research based on data collected by the Atlanta monitor shows that power plants are not responsible for thousands of deaths and serious heart and breathing problems caused by "particulate matter," microscopic bits of dust, soot and liquid droplets in the air.
But public health experts say the current science -- including the Atlanta-based research -- does not support that conclusion.
The debate already is taking on the intensity of similar science-centered health issues of the past and present: Does smoking cause cancer? How dangerous is asbestos? Is butter really bad for us?
As with those debates, the stakes are high. Particulate matter has emerged as one of the most deadly forms of air pollution. And decisions about millions of dollars of required pollution control may ride on how the science is interpreted.
While battle lines are being drawn based on what various scientific studies suggest, science does not yet offer all the answers. Most experts agree that no one knows for sure whether cars, power plants or other sources create the most dangerous fine particles.
Dwight Evans, Southern Co.'s executive vice president for external affairs, said the utility company does not oppose regulations that will cost it money, as long as studies prove that the health threats are real.
"We're saying let's be sure, if we spend the billions of dollars, that it is going to improve public health," he said.
Utility companies are making some expensive improvements to power plants to cut down on pollutants that virtually everyone agrees are harmful. But science-centered clashes continue to brew when it comes to fine particles and some other pollutants, including mercury and carbon dioxide.
The U.S. Environmental Protection Agency announced in 2000 it will require mercury reductions from power plants, which account for a third of the nation's man-made mercury releases. Regulations are expected by 2004.
Mercury threatens public health when it enters waterways and accumulates in fish. Consuming high levels of mercury can damage the brain and senses, and can even cause death in high doses. Mercury's greatest threat is to developing fetuses.
EPA acknowledged in 1998 that its studies could not quantify how much of the mercury in the nation's fish comes from U.S. power plants. But the agency said serious concerns warrant action.
Southern Co. is less convinced, saying that EPA's approach does not consider how much mercury travels across the globe and that cutting all U.S. power plant emissions of mercury may not address the problem.
"We think the science is not clear on this one yet," Evans said.
Southern Co. also has long questioned whether global warming is a problem that deserves urgent attention. Scientists agree that greenhouse gases, including carbon dioxide released by power plants, are contributing to global warming. Still uncertain, though, is exactly how and when global warming might threaten water resources, wildlife, health and agriculture.
Many environmentalists believe enough is known to require action now. Congress has considered several proposals to require power plants to cut carbon dioxide emissions. A proposal by President Bush advocates voluntary reductions.
While the debates about mercury and global warming have brewed for years, the discussions about the dangers of fine particles are more recent and have become intense.
Fine particles come from a variety of sources, including cars, power plants and even fireplaces. On days when levels are high, studies have found that more people go to emergency rooms and more people die prematurely, apparently due to breathing and heart problems.
Studies have estimated that fine particles cause at least 15,000 premature deaths each year. One environmental group estimates the number of deaths may be as high as 60,000.
Evans, of Southern Co., agrees that studies have demonstrated that fine particles are dangerous. But he says data from the Atlanta study show that particles coming from power plants are not a serious threat.
"We don't see them as causing significant health problems," he said. "Are there minor health problems? Possibly."
Experts say it's far too early to rule out any possible sources, especially based on the findings of one study. Dozens of studies have demonstrated the deadly nature of fine particles, and most researchers believe cars, power plants or both are the major culprits.
But it is true that no studies have demonstrated for certain that power plants are a culprit.
EPA, however, decided in 1997 that the threat was serious enough to warrant action. The agency plans to order the reduction of fine particles and will begin that process next year.