On the outer edge of the forest, Mammoth Cave National Park’s air quality manager Bob Carson shows off an elaborate monitoring station. In this fenced-off clearing, two humble-looking sheds house super-sensitive pollution detectors. One keeps tabs on how much soot—or particulate matter– is in the air. Carson says the instruments tell him not only how much particulate matter is in the air but what’s in that matter.
Mammoth Cave has some of the worst air quality, and worst visibility, of any national park in the country. Some forty coal-fired power plants operate within 200 miles of the park. These plants not only put out soot, but greenhouse gases and the neurotoxin, mercury. Carson says it’s the soot that makes skies so hazy over the park, especially in summer. A camera snaps shots over the park every day. And he can see just how the haze blurs tree-lined ridges, washes out colors. In the other shed, he explains how we know this soot creates the haze problem: these particles scatter light.
“We use this device to measure the particles that are scattering light. And we use that number to calculate our visual range, give us a mechanical visual range number in miles of what you can expect to see,” Carson says.
Carson says visibility hasn’t gotten any worse or any better over the past several years. But one attempt to improve it—for all national parks–came from the 1999 “haze rule.” Bruce Polkowsky is with the National Park Service’s air resources division. He helped write the rule.
Polkowski says the haze rule instructed states to make sure older power plants installed the best available technology to control emissions. And every ten years states have to assess their progress and file a plan to maintain it with the EPA. The first round plans are due now. But Polkowski says there’s a hold up—another rule that throws the haze rule into question. It’s the Clean Air Interstate Rule, or CAIR. The idea behind CAIR was to tackle pollution as a regional problem. If states joined the program, they had to reduce overall emissions from utilities, not individual plants. Again, Bruce Polkowsky.
“What the Clean Air Interstate Rule said is we’re doing such a massive reduction across the whole utility sector, that we’re just going to go ahead and say if your state implements the Clean Air Interstate Rule, and you do everything under that rule correctly, you, state, do not have to address best available retrofit technology for your utility sector,” Polkowsky says.
“Most of the southeastern states have already adopted their regulations assuming that because they joined CAIR, their utilities were fine. They didn’t have to go back and look at who was built when and what their control technologies are. They just said, we’re part of CAIR, we’re done. Now, that’s all in question,” says Polkowsky.
With the Clean Air Interstate Rule up in the air, states—and parks—are in a holding pattern with air quality plans. No one knows whether CAIR could be reinstated. With all the uncertainty, many states are lagging behind on turning in their haze plans. And the National Parks Conservation Association has sued the EPA over the stragglers. Spokesman Mark Wenzler says they want to make sure states move forward, regardless of the regulatory limbo. He says Kentucky’s plan has been submitted. Now it needs to be implemented.
“There’s a huge impact in Mammoth Cave. It’s one of the most polluted parks in the country. And so what we’re really looking to do is speed up the process of starting to clean up the worst offenders around Mammoth Cave to restore clean air to the park,” Wenzler says.
But even the haze rule Wenzler hopes states will take action on could be called into question. The Washington Post just reported that the EPA is close to changing it. Some fear the change could weaken protections for air quality in parks that are already suffering.