Those hazy, ozone days of summer

Remember Friday, Aug. 7 — when ozone levels at the Great Smokies Mountain National Park reached the unhealthy level of 113 parts per billion over an eight-hour period?

That same day, Asheville’s average was 106, according to state and local reports. That’s well above the 85 ppb ozone level the U.S. Environmental Protection Agency says poses a health risk: Prolonged or repeated exposure can make people more susceptible to respiratory infections and aggravate existing lung disorders, such as asthma, bronchitis or emphysema. Children and the elderly are particularly vulnerable, as are people exercising intensely or working outdoors. High ozone levels also damage many species of plants and animals.

So why wasn’t the public warned about Asheville’s high readings?

For starters, the EPA doesn’t mandate that state or local agencies do so — at least, not yet — according to meteorologist Brian Timin of the North Carolina Department of Environment and Natural Resources’ Air Quality Division in Raleigh. “When a high reading occurs, there is no requirement that we get the word out,” he says.

For another, ozone levels aren’t usually known until after the fact — unless you live in Charlotte or the Triangle area, where the state has initiated a forecasting-and-advisory service that includes daily postings on the Internet, Timin explains.

Both Charlotte and the Triangle are heavily populated areas that tend to have higher ozone readings than western North Carolina, he continues, adding, “It’s not worth doing a big [forecasting] program like that in Asheville, where high readings are fairly rare.”

Notifying the public — as Jim Renfro, air-quality specialist for the Smokies, did — is entirely voluntary, Timin notes.

“We started our advisory program this year,” says Renfro, who’s already recorded at least 19 high-ozone days in the Smokies this summer. “People expect clean air here, but a lot of times, the air may be cleaner in the cities they came from.”

The Smokies, he explains, get some of the highest ozone levels in the region, most of it blowing in from the southwest. But on Aug. 7, the winds were northeasterly: The pollution drifted in from North Carolina’s eastern cities, producing high ozone readings all over the mountain region.

Bryson City, located near the park, reported a high of 94 ppb that week (Linville’s high was 91), recounts DENR Regional Supervisor Paul Muller, checking the data before him. “It was a bad week for everyone,” he remarks.

Where did it come from?

Automobiles, coal-burning power plants and other industries emit nitrogen oxide. When it’s exposed to warm sunlight, it can produce ozone, Muller explains.

Temperatures above 85 degrees are most conducive to ozone creation; and when the mercury tops 90, it’s “even better,” says Timin.

Hot, heavily populated Atlanta, for instance, typically has one of the highest average ozone levels in the Southeast. But the Baltimore/Washington, D.C. area is probably the worst in the entire Eastern Seaboard, Renfro points out.

Add sulfur-oxide pollution — also produced by factories burning fossil fuels, as well as diesel-powered vehicles — to the mix, and you’ve got those lazy, hazy days of summer.

The ridgetops of the park and surrounding mountain counties get some of the highest cumulative readings in the East — day and night, Renfro observes. Ozone levels in valley areas such as Asheville, on the other hand, approach zero in the evenings.

Still, there is the occasional high: On Aug. 7, the ozone level here peaked at 114 during a one-hour period (average levels for the Asheville area are typically in the 40s and 50s). “We’ve never exceeded 100 before,” says technician Kevin Lance, who takes local readings for the Western North Carolina Regional Air Pollution Control Agency. Fortunately, those levels quickly subsided after the Aug. 7 high, Lance indicates.

That’s good news for Asheville, because the EPA will be monitoring ozone levels for the next few years, in order to establish whether specific cities, regions and states meet the new 85 ppb standard, Renfro notes. But the consistently high numbers in the Smokies could still impact the entire region, potentially forcing the state to come up with a plan for reducing nitrogen-oxide emissions in all areas surrounding the park, he says.

Already, the Tennessee Valley Authority — Tennessee’s major power producer — plans to reduce such emissions from its plants by 75 percent.

For the rest of us, Renfro advocates cutting back on our power use and auto trips … and contacting legislators to let them know we want clean air. “This is going to be one of our highest ozone seasons ever, [and] that’s unacceptable. People need to be aware of this,” Renfro declares, adding, “They’re the ones who can make a difference.”

Asheville-area citizens can get the most current ozone readings for our region by calling the state’s 1-800-AIRWISE service. And you can get air-quality reports — and a nifty near-live video — on the Smokies, updated every 15 minutes, by checking out this U.S. Forest Service Web site: www.aqd.nps.gov/ard1/parks/grsm/grsmvc.htm.