RALEIGH — North Carolina has recorded in 2010 its second-lowest number of high-ozone days in the past decade. A John Locke Foundation expert highlights that finding in a new Spotlight report.
The numbers look good, even though the federal government has made it easier since 2008 for North Carolina to register more high-ozone readings, said Dr. Roy Cordato, JLF Vice President for Research and Resident Scholar.
“Monitors across North Carolina averaged 2.65 high-ozone readings this year,” Cordato said. “That’s higher than the 0.33 average for 2009, but it’s lower than any other year since 2001. It’s far lower than the average of 27.33 high-ozone readings per monitor reported in 2002.”
The state recorded 106 high-ozone monitor readings on 26 separate days between April 1 and October 31, 2010, the official ozone season. Those numbers require several caveats, Cordato said.
“First, note that all high-ozone readings were recorded on just 26 days across the 214-day ozone season,” he explained. “Second, it’s important to remember that of the 39 ozone monitors scattered across the state, 32 high-ozone readings — 30 percent of the statewide total — are tied to just eight monitors in two areas, Charlotte and the Triad.”
“Plus ozone levels are very localized, even within metropolitan areas or regions,” Cordato added. “A monitor on one side of a county or region could register a high-ozone reading — what the bureaucrats call an exceedance — while, at the same time, a monitor a few miles away might not.”
In other words, this data does not indicate anything about air quality variations in a particular neighborhood or community, Cordato said.
It’s also important to note that the federal government has made changes in recent years that make it easier for North Carolina to register a high-ozone reading, Cordato warned.
“Before 2008, the Environmental Protection Agency set the standard for an ozone exceedance at 0.85 parts per billion in the atmosphere, sustained over an eight-hour period,” he explained. “In 2008, the number dropped to 0.76 parts per billion. That means a lower concentration of ozone now can trigger a high-ozone reading.”
If the feds had not changed the standards, North Carolina’s data would look even better, Cordato said. “If the pre-2008 EPA standard were still in place, North Carolina would have had only 11 high-ozone monitor readings for the entire 2010 season.”
People should keep the EPA’s changing standards in mind as they consider the state’s ozone data, Cordato said. “The EPA is considering lowering the ozone standard again below 0.70 parts per billion,” he said. “Such a change could trigger more high-ozone readings even though those readings would tell us nothing about improvements in air quality. It is generally thought that a standard as low as 0.65 parts per billion would put all of North Carolina and most of the country out of compliance with EPA guidelines.”
It’s important to focus on the real story hiding in the maze of data, Cordato said. “What is clear, particularly from statewide data, is that over the last seven years there has been a dramatic improvement in ozone levels across North Carolina,” Cordato said. “Air quality, at least with respect to ozone levels, has been getting better, not worse.”
Dr. Roy Cordato’s Spotlight report, ” Second-Best Ozone Season in a Decade: N.C.’s 2010 ozone season comes in like a lion, goes out like a lamb,” is available at the JLF Web site. For more information, please contact Cordato at (919) 828-3876 or [email protected]. To arrange an interview, contact Mitch Kokai at (919) 306-8736 or [email protected].