On a clear day: Visibility has improved, but you can’t (yet) see forever in WNC

Bill Jackson has spent his fair share of time in a haze. An air resource specialist for the U.S. Forest Service, he researches how air pollution reduces visibility in Western North Carolina and, more particularly, in areas like the Shining Rock Wilderness.

On a clear day, you can’t see forever in Shining Rock, and pollution is the cause.

“Haze is naturally occurring, and should have a bluish cast, not the smoky white we see some days,” Jackson told the nearly 20 people gathered to hear his report and others presented by air-quality experts at the annual Ozone Season Kickoff, hosted March 25 by the Land-of-Sky Regional Council.

Spring marks the beginning of when ozone is at its worst — April 1 through Sept. 30. The kickoff also announces the launch of daily air-quality forecasts, made by the North Carolina Division of Air Quality (see “Eye on Ozone”).

It’s also an opportunity to learn whether overall air quality is improving and what can be done to make it better. Since the federal Air Pollution Act of 1955, cleaner, clearer air has been a high priority in the United States and WNC. Conditions have improved, Jackson reported, but there’s a long way to go.

“Remedying of existing impairment — that’s where we are today,” he said.

Using years of data collected from an air-monitoring station in the Shining Rock Wilderness near Asheville, Jackson calculates that the current visibility range on the haziest days can be as low as 18 miles but as good as 121 miles on the clearest. Twelve years ago, visibility was often as low as 14 miles, so the air quality has improved, he mentioned.

“The goal is for visibility to be 73 miles on the haziest days,” Jackson said, noting that we’re on track to meet that target by 2064, and maybe sooner.

“Elsewhere in the U.S, things are better,” he noted. Data released by State of the Air, an offshoot of the American Lung Association, shows that most of the cities with the best air quality are in the Midwest and West regions — Santa Fe, N.M., and Cheyenne, Wyo., for example. Other than the metro area of Sarasota, Fla., few cities on the East Coast make the list.

How can the region do better? “For [WNC], any reduction in sulfur dioxide will be an improvement,” Jackson said.

The result of an elevated presence of fine particles or particulate matter (PM 2.5, in the technical parlance), haze consists of sulfates, nitrates, soil, elemental carbon and organics in the air. Add manmade contaminants, particularly through burning hydrocarbons such as coal, gasoline and diesel fuel, and you get smog, a term coined by London physician Harold Des Veaux in 1905. From the late 19th century into the 1940s, a series of “killer smog” events in Europe and the U.S. spurred much of the clean-air legislation and guidelines used today.

Recent initiatives and changes have all helped reduced sulfur dioxide levels, said Jackson. He mentioned such changes as the North Carolina Clean Smoke Stacks Act of 2002, the reduction of power-plant emissions from the Tennessee Valley Authority and the rise of alternative-fuel vehicles.

Despite improvements, however, air-quality problems persist and raise serious health risks.

“Fine particle concentration is correlated to mortality,’ said Paul Muller, regional supervisor of DAQ, and a presenter at the kickoff. According to the EPA, fine particles are measured in micrograms per cubic meter. That is, they’re typically less than one-seventh the average width of a human hair and can lodge deep within the lungs. Ozone and fine particulates can exacerbate asthma and allergies, and lead to lung and heart disease.

Luckily, Asheville’s air remains below levels the EPA deems unsafe.

And Jackson says there has been noticeable improvement in regional air quality.

“Ten years ago you couldn’t see Mount Pisgah from the Smoky Park [Capt. Jeff Bowen] Bridge,” said Jackson. “I expect when the 2012 data returns, it will show improvements.”

— Mat Payne is a local freelance writer.