It was just about a year ago when I visited Mesa Verde National Park for a story. Standing atop Chapin Mesa, I could easily see why the Ancestral Puebloans who built the cliff dwellings settled here.
    Let me rephrase that. I could understand why, as the visibility was so poor that I couldn't see terribly far, and surely the great, expansive vistas that must have existed 800+ years ago must have played a role in their decision to settle here, as they would be able to see enemies approaching from a great distance.
    These days, on clear days you can look south from the mesa top and see the geologic formation that led to the naming of Shiprock, New Mexico. But on this day the view was a hazy veil.
    Now, if you've shared that experience, or stood on Moro Rock in Sequoia National Park or atop Clingmans Dome in Great Smoky Mountains National Park and were disappointed by the views, or struggled to breath in the ozone-thick air at Shenandoah National Park or Cape Cod National Seashore, then you probably can understand my surprise when I came across the National Park Service's recently released study on air quality in the parks. For right there, under the introduction, the report notes that, "the NPS is exceeding air quality performance goals for 2005, with 68 percent of the reporting parks showing stable or improving air quality trends generally, 78 percent meeting national ambient air quality standards, and 100 percent meeting visibility goals."
    I thought that had to be a typo or a misprint so I called up Chris Shaver, who works in the agency's Air Resources Division in Denver and helped prepare the report.

    Now, before I move on, what's important to remember is that the National Park Service cannot control pollution sources located outside the national park system, and those are the sources that by and large create air pollution inside the parks.
    Got that? OK. Let's continue.
    What I struggle with when reading this report is that part of the explanation for the Park Service's high performance rating lies in the fact that the Park Service considers "stable ... air-quality trends" a sign of success." That's right, "stable" equates with success when you're talking air quality in the parks.
    So if the visibility atop Clingmans Dome today was only 15 miles and a year later it still was only 15 miles, well, that's stable, so from the NPS's viewpoint, that's apparently a measure of success.
    When Ms. Shaver got on the phone, I got right to the point, asking her if stable conditions were indeed a sign of success?
    "Under the theory of first do no harm, I guess yes," she replied, adding that, "In many of our areas the air is cleaner than you experience in urban areas. So having stability is a good thing."
    I guess you can't quibble with that rationale. But still, when you can't see the mountains that lent their name to Great Smoky Mountains National Park or the San Joaquin Valley from Moro Rock in Sequoia, you naturally begin to wonder if stable is indeed success when it comes to air quality.
    "Stability and protecting the status quo is viewed as a good thing," Ms. Shaver maintained. "Of course, seeing air quality improve is the preferred objective."

    How Do You Measure Air Quality in the Parks?

    When the NPS sat down to crunch the numbers and produce this report, it took what I'll call the "20-20" approach. For each of the 68 park units it monitored during 2005, it looked at the "20 percent clearest days and the 20 percent haziest days" and compared them to previous data.
    In the visibility category, "all 30 parks that have monitored visibility for at least six years have stable or improving visibility on both the clear and hazy days," reads the report. "In other words, 100 percent are meeting the visibility goal.
    "On the clearest days, almost half the parks are showing improvement, including Shenandoah and Acadia national parks in the eastern U.S. and several sites in the northwest U.S., California, Colorado Plateau and Rocky Mountain areas, and Alaska."
    Now don't let that news make you think all is well and fine in the national parks when it comes to air quality. 
    Nitrogen depositions, possibly caused in part by fossil fuels combustion, are up in Bandelier National Monument, Canyonlands National Park, Craters of the Moon National Monument, Gila Cliff Dwellings National Monument, Glacier National Park, Grand Canyon National Park, Little Bighorn Battlefield National Monument, Rocky Mountain National Park and Yellowstone National Park.
    And ozone levels, while relatively stable the past ten years over Great Smoky, Shenandoah and Mammoth Cave national parks, are on the rise over Canyonlands, Craters of the Moon, Death Valley National Park, Glacier, Grand Canyon, Mesa Verde, North Cascades National Park, Rocky Mountain, Sequoia and Yellowstone.
    Combined, these problems are a growing concern with the NPS.
    "We've been talking in earnest with the Western states over what is happening and why," said Ms. Shaver, adding that no conclusions have been reached just yet. "There are a number of possibilities and we continue to work on it. Everything between global background (levels) perhaps increasing to a lot of development, oil and gas development, in these parts. There's urban development along the Front Range of Colorado. It may be getting warmer, which contributes to ozone. We're seeing ozone going up year-round in many of the (Western) parks."
    Ten parks failed in 2005 to meet National Ambient Air Quality Standards for one or more of the Environmental Protection Agency standards for ozone, particulate matter, or sulfur dioxide: Acadia, Great Smoky, Joshua Tree, Sequoia, Kings Canyon, Shenandoah and Yosemite are above the ozone standard; Rocky Mountain itself has recorded ozone levels below the level but still falls within an EPA ozone non-attainment area; Point Reyes, while having no on-site monitoring for ozone, is part of an EPA non-attainment area, and; Hawaii Volcanoes National Park exceeds sulfur dioxide levels on occasion, but that's attributed to the volcano itself, not human sources.

    NPCA Has Different View On the Data

    Over at the National Parks Conservation Association, Mark Wenzler agreed that there have been some improvements in air quality over the parks in recent years. But he also pointed out that while the NPS says that 68 percent of the park units that it monitors show "stable or improving air quality trends," that means more than one-third of the parks surveyed are seeing their air quality decline.
    "That's a pretty big story," he told me. "All parks are supposed to be getting better."
    Plus, the agency is monitoring just 68 of its 390 units. What's going on in the other 322?
    "What the parks should be doing, and most haven't done," added Wenzler, "is establish 'critical loads.' They need to go into each park individually and assess the conditions and determine what the habitat can bear. Until you do that, you don't have a strong scientific basis to object to new air pollution sources."
    With critical load data in place, officials will have a "tool that you use to have a baseline so you can be able to say, 'We can allow X amount of pollution in the park, but no more. This is the line we have to draw,'" said Wenzler.
    Back at the NPS, Ms. Shaver agreed that critical load data is needed. So far, Rocky Mountain National Park has succeeded in that arena, signing a letter with the state of Colorado within the past week or so that outlines what park officials "think is the critical load for nitrogen at the park."
    "The question is, what's the next step?" she added. "Can we come up with some trajectory that can bring us closer to the natural condition, or the desired condition, for the national park?"

    Time To Think About the Rest of the Earth's Species 

    One thing that made it somewhat easy for Rocky Mountain officials to address the critical load question is that the park had more than a quarter-century worth of research it could turn to when trying to define the goal. Not many other parks can say that.
    In the coming weeks the EPA is planning a workshop on critical load matters, and Park Service representatives plan to attend to "sort of figure out how a critical load management concept or assessment concept fits in air-quality planning efforts," Ms. Shaver told me. "To date, most of what is done to reduce air pollution has been done for public health reasons, not any ecological reasons."
    However, she pointed out, officials are taking a new approach to consider ecological systems, not just public health, when dealing with pollution.
    "It's a reflection that we're not a single-species planet and we should start paying attention to what we're doing to the natural system," Ms. Shaver said.
    Of course, what also needs to be done is for the Bush administration to step up to the plate, said the NPCA's Wenzler.
    "They have this approach of giving with one hand and taking away with the other," he said, referring to the administration's attempts to weaken air-pollution controls for power plants.
    "Their air-pollution legislation, known as Clear Skies, which is still stuck in Congress, would take authority away from the Park Service to object to new energy development," Wenzler said. "Here's the administration saying it cares about the parks, but then they have this legislative proposal that would take away the NPS's authority to do anything about" potential air-pollution sources.
    Yes, as you can see, when it comes to the national parks, air quality is anything but clear.